Merge branch 'master' into beorn7/storage3

CHANGELOG.md

@@ -1,20 +1,18 @@
-## 0.17.0 / unreleased
+## 0.17.0 / 2016-03-02
 
 This version no longer works with Alertmanager 0.0.4 and earlier!
 The alerting rule syntax has changed as well but the old syntax is supported
 up until version 0.18.
 
 All regular expressions in PromQL are anchored now, matching the behavior of
-regular expressions in config files. Expressions in rules, alerts or dashboards
-need to be changed if they don't match the full value so far (for example
-`http_requests_total{status=~"^5"}` won't match anything anymore and needs to
-be changed to `http_requests_total{status=~"5.."}`).
+regular expressions in config files.
 
 * [CHANGE] Integrate with Alertmanager 0.1.0 and higher
 * [CHANGE] Degraded storage mode renamed to rushed mode
 * [CHANGE] New alerting rule syntax
 * [CHANGE] Add label validation on ingestion
 * [CHANGE] Regular expression matchers in PromQL are anchored
+* [FEATURE] Add `without` aggregation modifier
 * [FEATURE] Send alert resolved notifications to Alertmanager
 * [FEATURE] Allow millisecond precision in configuration file
 * [FEATURE] Support AirBnB's Smartstack Nerve for service discovery
@@ -26,6 +24,9 @@ be changed to `http_requests_total{status=~"5.."}`).
 * [BUGFIX] Handle OPTIONS HTTP requests to the API correctly
 * [BUGFIX] Parsing of ranges in PromQL fixed
 * [BUGFIX] Correctly validate URL flag parameters
+* [BUGFIX] Log argument parse errors
+* [BUGFIX] Properly handle creation of target with bad TLS config
+* [BUGFIX] Fix of checkpoint timing issue
 
 ## 0.16.2 / 2016-01-18
 

Makefile

@@ -23,7 +23,7 @@ all: format build test
 
 style:
 	@echo ">> checking code style"
-	@! gofmt -d **/*.go | grep '^'
+	@! gofmt -d $(shell find . -path ./vendor -prune -o -name '*.go' -print) | grep '^'
 
 test:
 	@echo ">> running tests"

cmd/prometheus/config.go

@@ -26,7 +26,7 @@ import (
 
 	"github.com/asaskevich/govalidator"
 	"github.com/prometheus/common/log"
-	"github.com/prometheus/prometheus/notification"
+	"github.com/prometheus/prometheus/notifier"
 	"github.com/prometheus/prometheus/promql"
 	"github.com/prometheus/prometheus/storage/local"
 	"github.com/prometheus/prometheus/storage/local/index"
@@ -42,11 +42,11 @@ var cfg = struct {
 	printVersion bool
 	configFile   string
 
-	storage      local.MemorySeriesStorageOptions
-	notification notification.HandlerOptions
-	queryEngine  promql.EngineOptions
-	web          web.Options
-	remote       remote.Options
+	storage     local.MemorySeriesStorageOptions
+	notifier    notifier.Options
+	queryEngine promql.EngineOptions
+	web         web.Options
+	remote      remote.Options
 
 	prometheusURL string
 	influxdbURL   string
@@ -203,15 +203,15 @@ func init() {
 
 	// Alertmanager.
 	cfg.fs.StringVar(
-		&cfg.notification.AlertmanagerURL, "alertmanager.url", "",
+		&cfg.notifier.AlertmanagerURL, "alertmanager.url", "",
 		"The URL of the alert manager to send notifications to.",
 	)
 	cfg.fs.IntVar(
-		&cfg.notification.QueueCapacity, "alertmanager.notification-queue-capacity", 10000,
+		&cfg.notifier.QueueCapacity, "alertmanager.notification-queue-capacity", 10000,
 		"The capacity of the queue for pending alert manager notifications.",
 	)
 	cfg.fs.DurationVar(
-		&cfg.notification.Timeout, "alertmanager.timeout", 10*time.Second,
+		&cfg.notifier.Timeout, "alertmanager.timeout", 10*time.Second,
 		"Alert manager HTTP API timeout.",
 	)
 

cmd/prometheus/main.go

@@ -31,7 +31,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 
 	"github.com/prometheus/prometheus/config"
-	"github.com/prometheus/prometheus/notification"
+	"github.com/prometheus/prometheus/notifier"
 	"github.com/prometheus/prometheus/promql"
 	"github.com/prometheus/prometheus/retrieval"
 	"github.com/prometheus/prometheus/rules"
@@ -84,16 +84,16 @@ func Main() int {
 	}
 
 	var (
-		notificationHandler = notification.New(&cfg.notification)
-		targetManager       = retrieval.NewTargetManager(sampleAppender)
-		queryEngine         = promql.NewEngine(memStorage, &cfg.queryEngine)
+		notifier      = notifier.New(&cfg.notifier)
+		targetManager = retrieval.NewTargetManager(sampleAppender)
+		queryEngine   = promql.NewEngine(memStorage, &cfg.queryEngine)
 	)
 
 	ruleManager := rules.NewManager(&rules.ManagerOptions{
-		SampleAppender:      sampleAppender,
-		NotificationHandler: notificationHandler,
-		QueryEngine:         queryEngine,
-		ExternalURL:         cfg.web.ExternalURL,
+		SampleAppender: sampleAppender,
+		Notifier:       notifier,
+		QueryEngine:    queryEngine,
+		ExternalURL:    cfg.web.ExternalURL,
 	})
 
 	flags := map[string]string{}
@@ -110,7 +110,7 @@ func Main() int {
 
 	webHandler := web.New(memStorage, queryEngine, ruleManager, status, &cfg.web)
 
-	reloadables = append(reloadables, status, targetManager, ruleManager, webHandler, notificationHandler)
+	reloadables = append(reloadables, status, targetManager, ruleManager, webHandler, notifier)
 
 	if !reloadConfig(cfg.configFile, reloadables...) {
 		return 1
@@ -153,14 +153,14 @@ func Main() int {
 	}
 	// The storage has to be fully initialized before registering.
 	prometheus.MustRegister(memStorage)
-	prometheus.MustRegister(notificationHandler)
+	prometheus.MustRegister(notifier)
 	prometheus.MustRegister(configSuccess)
 	prometheus.MustRegister(configSuccessTime)
 
-	// The notification handler is a dependency of the rule manager. It has to be
+	// The notifieris a dependency of the rule manager. It has to be
 	// started before and torn down afterwards.
-	go notificationHandler.Run()
-	defer notificationHandler.Stop()
+	go notifier.Run()
+	defer notifier.Stop()
 
 	go ruleManager.Run()
 	defer ruleManager.Stop()

cmd/promtool/main.go

@@ -199,7 +199,7 @@ func VersionCmd(t cli.Term, _ ...string) int {
 	if err := tmpl.ExecuteTemplate(&buf, "version", version.Map); err != nil {
 		panic(err)
 	}
-	t.Out(strings.TrimSpace(buf.String()))
+	fmt.Fprintln(t.Out(), strings.TrimSpace(buf.String()))
 	return 0
 }
 

notifier/notifier.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package notification
+package notifier
 
 import (
 	"bytes"
@@ -44,9 +44,9 @@ const (
 
 // Handler is responsible for dispatching alert notifications to an
 // alert manager service.
-type Handler struct {
+type Notifier struct {
 	queue model.Alerts
-	opts  *HandlerOptions
+	opts  *Options
 
 	more   chan struct{}
 	mtx    sync.RWMutex
@@ -62,18 +62,18 @@ type Handler struct {
 }
 
 // HandlerOptions are the configurable parameters of a Handler.
-type HandlerOptions struct {
+type Options struct {
 	AlertmanagerURL string
 	QueueCapacity   int
 	Timeout         time.Duration
 	ExternalLabels  model.LabelSet
 }
 
-// NewHandler constructs a new Handler.
-func New(o *HandlerOptions) *Handler {
+// New constructs a neww Notifier.
+func New(o *Options) *Notifier {
 	ctx, cancel := context.WithCancel(context.Background())
 
-	return &Handler{
+	return &Notifier{
 		queue:  make(model.Alerts, 0, o.QueueCapacity),
 		ctx:    ctx,
 		cancel: cancel,
@@ -124,7 +124,7 @@ func New(o *HandlerOptions) *Handler {
 
 // ApplyConfig updates the status state as the new config requires.
 // Returns true on success.
-func (n *Handler) ApplyConfig(conf *config.Config) bool {
+func (n *Notifier) ApplyConfig(conf *config.Config) bool {
 	n.mtx.Lock()
 	defer n.mtx.Unlock()
 
@@ -134,14 +134,14 @@ func (n *Handler) ApplyConfig(conf *config.Config) bool {
 
 const maxBatchSize = 64
 
-func (n *Handler) queueLen() int {
+func (n *Notifier) queueLen() int {
 	n.mtx.RLock()
 	defer n.mtx.RUnlock()
 
 	return len(n.queue)
 }
 
-func (n *Handler) nextBatch() []*model.Alert {
+func (n *Notifier) nextBatch() []*model.Alert {
 	n.mtx.Lock()
 	defer n.mtx.Unlock()
 
@@ -159,7 +159,7 @@ func (n *Handler) nextBatch() []*model.Alert {
 }
 
 // Run dispatches notifications continuously.
-func (n *Handler) Run() {
+func (n *Notifier) Run() {
 	// Just warn once in the beginning to prevent noisy logs.
 	if n.opts.AlertmanagerURL == "" {
 		log.Warnf("No AlertManager configured, not dispatching any alerts")
@@ -200,9 +200,9 @@ func (n *Handler) Run() {
 	}
 }
 
-// SubmitReqs queues the given notification requests for processing.
+// Send queues the given notification requests for processing.
 // Panics if called on a handler that is not running.
-func (n *Handler) Send(alerts ...*model.Alert) {
+func (n *Notifier) Send(alerts ...*model.Alert) {
 	n.mtx.Lock()
 	defer n.mtx.Unlock()
 
@@ -230,7 +230,7 @@ func (n *Handler) Send(alerts ...*model.Alert) {
 }
 
 // setMore signals that the alert queue has items.
-func (n *Handler) setMore() {
+func (n *Notifier) setMore() {
 	// If we cannot send on the channel, it means the signal already exists
 	// and has not been consumed yet.
 	select {
@@ -239,11 +239,11 @@ func (n *Handler) setMore() {
 	}
 }
 
-func (n *Handler) postURL() string {
+func (n *Notifier) postURL() string {
 	return strings.TrimRight(n.opts.AlertmanagerURL, "/") + alertPushEndpoint
 }
 
-func (n *Handler) send(alerts ...*model.Alert) error {
+func (n *Notifier) send(alerts ...*model.Alert) error {
 	// Attach external labels before sending alerts.
 	for _, a := range alerts {
 		for ln, lv := range n.opts.ExternalLabels {
@@ -272,14 +272,14 @@ func (n *Handler) send(alerts ...*model.Alert) error {
 }
 
 // Stop shuts down the notification handler.
-func (n *Handler) Stop() {
+func (n *Notifier) Stop() {
 	log.Info("Stopping notification handler...")
 
 	n.cancel()
 }
 
 // Describe implements prometheus.Collector.
-func (n *Handler) Describe(ch chan<- *prometheus.Desc) {
+func (n *Notifier) Describe(ch chan<- *prometheus.Desc) {
 	ch <- n.latency.Desc()
 	ch <- n.errors.Desc()
 	ch <- n.sent.Desc()
@@ -289,7 +289,7 @@ func (n *Handler) Describe(ch chan<- *prometheus.Desc) {
 }
 
 // Collect implements prometheus.Collector.
-func (n *Handler) Collect(ch chan<- prometheus.Metric) {
+func (n *Notifier) Collect(ch chan<- prometheus.Metric) {
 	n.queueLength.Set(float64(n.queueLen()))
 
 	ch <- n.latency

notifier/notifier_test.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package notification
+package notifier
 
 import (
 	"encoding/json"
@@ -50,8 +50,8 @@ func TestHandlerPostURL(t *testing.T) {
 			out: "http://localhost:9093/prefix/api/v1/alerts",
 		},
 	}
-	h := &Handler{
-		opts: &HandlerOptions{},
+	h := &Notifier{
+		opts: &Options{},
 	}
 
 	for _, c := range cases {
@@ -63,7 +63,7 @@ func TestHandlerPostURL(t *testing.T) {
 }
 
 func TestHandlerNextBatch(t *testing.T) {
-	h := New(&HandlerOptions{})
+	h := New(&Options{})
 
 	for i := range make([]struct{}, 2*maxBatchSize+1) {
 		h.queue = append(h.queue, &model.Alert{
@@ -146,7 +146,7 @@ func TestHandlerSend(t *testing.T) {
 
 	defer server.Close()
 
-	h := New(&HandlerOptions{
+	h := New(&Options{
 		AlertmanagerURL: server.URL,
 		Timeout:         time.Minute,
 		ExternalLabels:  model.LabelSet{"a": "b"},
@@ -202,7 +202,7 @@ func TestHandlerFull(t *testing.T) {
 		}
 	}))
 
-	h := New(&HandlerOptions{
+	h := New(&Options{
 		AlertmanagerURL: server.URL,
 		Timeout:         time.Second,
 		QueueCapacity:   3 * maxBatchSize,

promql/lex_test.go

@@ -99,6 +99,26 @@ var tests = []struct {
 		input:    "0x123",
 		expected: []item{{itemNumber, 0, "0x123"}},
 	},
+	// Test strings.
+	{
+		input:    "\"test\\tsequence\"",
+		expected: []item{{itemString, 0, `"test\tsequence"`}},
+	},
+	{
+		input:    "\"test\\\\.expression\"",
+		expected: []item{{itemString, 0, `"test\\.expression"`}},
+	},
+	{
+		input: "\"test\\.expression\"",
+		expected: []item{
+			{itemError, 0, "unknown escape sequence U+002E '.'"},
+			{itemString, 0, `"test\.expression"`},
+		},
+	},
+	{
+		input:    "`test\\.expression`",
+		expected: []item{{itemString, 0, "`test\\.expression`"}},
+	},
 	{
 		// See https://github.com/prometheus/prometheus/issues/939.
 		input: ".٩",

promql/parse.go

@@ -530,35 +530,34 @@ func (p *parser) expr() Expr {
 		rhs := p.unaryExpr()
 
 		// Assign the new root based on the precedence of the LHS and RHS operators.
-		if lhs, ok := expr.(*BinaryExpr); ok && lhs.Op.precedence() < op.precedence() {
-			expr = &BinaryExpr{
-				Op:  lhs.Op,
-				LHS: lhs.LHS,
-				RHS: &BinaryExpr{
-					Op:             op,
-					LHS:            lhs.RHS,
-					RHS:            rhs,
-					VectorMatching: vecMatching,
-					ReturnBool:     returnBool,
-				},
-				VectorMatching: lhs.VectorMatching,
-			}
-			if op.isComparisonOperator() && !returnBool && rhs.Type() == model.ValScalar && lhs.RHS.Type() == model.ValScalar {
-				p.errorf("comparisons between scalars must use BOOL modifier")
-			}
-		} else {
-			expr = &BinaryExpr{
-				Op:             op,
-				LHS:            expr,
-				RHS:            rhs,
-				VectorMatching: vecMatching,
-				ReturnBool:     returnBool,
-			}
-			if op.isComparisonOperator() && !returnBool && rhs.Type() == model.ValScalar && expr.Type() == model.ValScalar {
-				p.errorf("comparisons between scalars must use BOOL modifier")
-			}
-		}
+		expr = p.balance(expr, op, rhs, vecMatching, returnBool)
+	}
+}
 
+func (p *parser) balance(lhs Expr, op itemType, rhs Expr, vecMatching *VectorMatching, returnBool bool) *BinaryExpr {
+	if lhsBE, ok := lhs.(*BinaryExpr); ok && lhsBE.Op.precedence() < op.precedence() {
+		balanced := p.balance(lhsBE.RHS, op, rhs, vecMatching, returnBool)
+		if lhsBE.Op.isComparisonOperator() && !lhsBE.ReturnBool && balanced.Type() == model.ValScalar && lhsBE.LHS.Type() == model.ValScalar {
+			p.errorf("comparisons between scalars must use BOOL modifier")
+		}
+		return &BinaryExpr{
+			Op:             lhsBE.Op,
+			LHS:            lhsBE.LHS,
+			RHS:            balanced,
+			VectorMatching: lhsBE.VectorMatching,
+			ReturnBool:     lhsBE.ReturnBool,
+		}
+	} else {
+		if op.isComparisonOperator() && !returnBool && rhs.Type() == model.ValScalar && lhs.Type() == model.ValScalar {
+			p.errorf("comparisons between scalars must use BOOL modifier")
+		}
+		return &BinaryExpr{
+			Op:             op,
+			LHS:            lhs,
+			RHS:            rhs,
+			VectorMatching: vecMatching,
+			ReturnBool:     returnBool,
+		}
 	}
 }
 

promql/parse_test.go

@@ -124,6 +124,20 @@ var testExpr = []struct {
 				}},
 			},
 		},
+	}, {
+		input: "1 < bool 2 - 1 * 2",
+		expected: &BinaryExpr{
+			Op:         itemLSS,
+			ReturnBool: true,
+			LHS:        &NumberLiteral{1},
+			RHS: &BinaryExpr{
+				Op:  itemSUB,
+				LHS: &NumberLiteral{2},
+				RHS: &BinaryExpr{
+					Op: itemMUL, LHS: &NumberLiteral{1}, RHS: &NumberLiteral{2},
+				},
+			},
+		},
 	}, {
 		input: "-some_metric", expected: &UnaryExpr{
 			Op: itemSUB,

promql/test.go

@@ -425,7 +425,7 @@ func (t *Test) Run() error {
 	return nil
 }
 
-// exec processes a single step of the test
+// exec processes a single step of the test.
 func (t *Test) exec(tc testCommand) error {
 	switch cmd := tc.(type) {
 	case *clearCmd:

retrieval/discovery/consul.go

@@ -15,7 +15,6 @@ package discovery
 
 import (
 	"fmt"
-	"net/http"
 	"strconv"
 	"strings"
 	"sync"
@@ -24,6 +23,7 @@ import (
 	consul "github.com/hashicorp/consul/api"
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
 
 	"github.com/prometheus/prometheus/config"
 )
@@ -113,52 +113,24 @@ func NewConsulDiscovery(conf *config.ConsulSDConfig) (*ConsulDiscovery, error) {
 	return cd, nil
 }
 
-// Sources implements the TargetProvider interface.
-func (cd *ConsulDiscovery) Sources() []string {
-	clientConf := *cd.clientConf
-	clientConf.HttpClient = &http.Client{Timeout: 5 * time.Second}
-
-	client, err := consul.NewClient(&clientConf)
-	if err != nil {
-		// NewClient always returns a nil error.
-		panic(fmt.Errorf("discovery.ConsulDiscovery.Sources: %s", err))
-	}
-
-	srvs, _, err := client.Catalog().Services(nil)
-	if err != nil {
-		log.Errorf("Error refreshing service list: %s", err)
-		return nil
-	}
-	cd.mu.Lock()
-	defer cd.mu.Unlock()
-
-	srcs := make([]string, 0, len(srvs))
-	for name := range srvs {
-		if _, ok := cd.scrapedServices[name]; len(cd.scrapedServices) == 0 || ok {
-			srcs = append(srcs, name)
-		}
-	}
-	return srcs
-}
-
 // Run implements the TargetProvider interface.
-func (cd *ConsulDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
+func (cd *ConsulDiscovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	defer close(ch)
 	defer cd.stop()
 
 	update := make(chan *consulService, 10)
-	go cd.watchServices(update, done)
+	go cd.watchServices(update, ctx.Done())
 
 	for {
 		select {
-		case <-done:
+		case <-ctx.Done():
 			return
 		case srv := <-update:
 			if srv.removed {
 				close(srv.done)
 
 				// Send clearing update.
-				ch <- config.TargetGroup{Source: srv.name}
+				ch <- []*config.TargetGroup{{Source: srv.name}}
 				break
 			}
 			// Launch watcher for the service.
@@ -244,7 +216,7 @@ func (cd *ConsulDiscovery) watchServices(update chan<- *consulService, done <-ch
 
 // watchService retrieves updates about srv from Consul's service endpoint.
 // On a potential update the resulting target group is sent to ch.
-func (cd *ConsulDiscovery) watchService(srv *consulService, ch chan<- config.TargetGroup) {
+func (cd *ConsulDiscovery) watchService(srv *consulService, ch chan<- []*config.TargetGroup) {
 	catalog := cd.client.Catalog()
 	for {
 		nodes, meta, err := catalog.Service(srv.name, "", &consul.QueryOptions{
@@ -288,7 +260,11 @@ func (cd *ConsulDiscovery) watchService(srv *consulService, ch chan<- config.Tar
 		default:
 			// Continue.
 		}
-		ch <- srv.tgroup
+		// TODO(fabxc): do a copy for now to avoid races. The integration
+		// needs needs some general cleanup.
+		tg := srv.tgroup
+		ch <- []*config.TargetGroup{&tg}
+
 		cd.mu.Unlock()
 	}
 }

retrieval/discovery/dns.go

@@ -24,6 +24,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
 
 	"github.com/prometheus/prometheus/config"
 )
@@ -91,7 +92,7 @@ func NewDNSDiscovery(conf *config.DNSSDConfig) *DNSDiscovery {
 }
 
 // Run implements the TargetProvider interface.
-func (dd *DNSDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
+func (dd *DNSDiscovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	defer close(ch)
 
 	ticker := time.NewTicker(dd.interval)
@@ -104,23 +105,15 @@ func (dd *DNSDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{})
 		select {
 		case <-ticker.C:
 			dd.refreshAll(ch)
-		case <-done:
+		case <-ctx.Done():
 			return
 		}
 	}
 }
 
-// Sources implements the TargetProvider interface.
-func (dd *DNSDiscovery) Sources() []string {
-	var srcs []string
-	for _, name := range dd.names {
-		srcs = append(srcs, name)
-	}
-	return srcs
-}
-
-func (dd *DNSDiscovery) refreshAll(ch chan<- config.TargetGroup) {
+func (dd *DNSDiscovery) refreshAll(ch chan<- []*config.TargetGroup) {
 	var wg sync.WaitGroup
+
 	wg.Add(len(dd.names))
 	for _, name := range dd.names {
 		go func(n string) {
@@ -130,10 +123,11 @@ func (dd *DNSDiscovery) refreshAll(ch chan<- config.TargetGroup) {
 			wg.Done()
 		}(name)
 	}
+
 	wg.Wait()
 }
 
-func (dd *DNSDiscovery) refresh(name string, ch chan<- config.TargetGroup) error {
+func (dd *DNSDiscovery) refresh(name string, ch chan<- []*config.TargetGroup) error {
 	response, err := lookupAll(name, dd.qtype)
 	dnsSDLookupsCount.Inc()
 	if err != nil {
@@ -141,7 +135,8 @@ func (dd *DNSDiscovery) refresh(name string, ch chan<- config.TargetGroup) error
 		return err
 	}
 
-	var tg config.TargetGroup
+	tg := &config.TargetGroup{}
+
 	for _, record := range response.Answer {
 		target := model.LabelValue("")
 		switch addr := record.(type) {
@@ -166,7 +161,7 @@ func (dd *DNSDiscovery) refresh(name string, ch chan<- config.TargetGroup) error
 	}
 
 	tg.Source = name
-	ch <- tg
+	ch <- []*config.TargetGroup{tg}
 
 	return nil
 }

retrieval/discovery/ec2.go

@@ -23,6 +23,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/defaults"
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
 
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/prometheus/prometheus/config"
@@ -46,7 +47,6 @@ const (
 // the TargetProvider interface.
 type EC2Discovery struct {
 	aws      *aws.Config
-	done     chan struct{}
 	interval time.Duration
 	port     int
 }
@@ -62,14 +62,13 @@ func NewEC2Discovery(conf *config.EC2SDConfig) *EC2Discovery {
 			Region:      &conf.Region,
 			Credentials: creds,
 		},
-		done:     make(chan struct{}),
 		interval: time.Duration(conf.RefreshInterval),
 		port:     conf.Port,
 	}
 }
 
 // Run implements the TargetProvider interface.
-func (ed *EC2Discovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
+func (ed *EC2Discovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	defer close(ch)
 
 	ticker := time.NewTicker(ed.interval)
@@ -80,7 +79,7 @@ func (ed *EC2Discovery) Run(ch chan<- config.TargetGroup, done <-chan struct{})
 	if err != nil {
 		log.Error(err)
 	} else {
-		ch <- *tg
+		ch <- []*config.TargetGroup{tg}
 	}
 
 	for {
@@ -90,19 +89,14 @@ func (ed *EC2Discovery) Run(ch chan<- config.TargetGroup, done <-chan struct{})
 			if err != nil {
 				log.Error(err)
 			} else {
-				ch <- *tg
+				ch <- []*config.TargetGroup{tg}
 			}
-		case <-done:
+		case <-ctx.Done():
 			return
 		}
 	}
 }
 
-// Sources implements the TargetProvider interface.
-func (ed *EC2Discovery) Sources() []string {
-	return []string{*ed.aws.Region}
-}
-
 func (ed *EC2Discovery) refresh() (*config.TargetGroup, error) {
 	ec2s := ec2.New(ed.aws)
 	tg := &config.TargetGroup{

retrieval/discovery/file.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
 	"gopkg.in/fsnotify.v1"
 	"gopkg.in/yaml.v2"
 
@@ -53,23 +54,6 @@ func NewFileDiscovery(conf *config.FileSDConfig) *FileDiscovery {
 	}
 }
 
-// Sources implements the TargetProvider interface.
-func (fd *FileDiscovery) Sources() []string {
-	var srcs []string
-	// As we allow multiple target groups per file we have no choice
-	// but to parse them all.
-	for _, p := range fd.listFiles() {
-		tgroups, err := readFile(p)
-		if err != nil {
-			log.Errorf("Error reading file %q: %s", p, err)
-		}
-		for _, tg := range tgroups {
-			srcs = append(srcs, tg.Source)
-		}
-	}
-	return srcs
-}
-
 // listFiles returns a list of all files that match the configured patterns.
 func (fd *FileDiscovery) listFiles() []string {
 	var paths []string
@@ -103,7 +87,7 @@ func (fd *FileDiscovery) watchFiles() {
 }
 
 // Run implements the TargetProvider interface.
-func (fd *FileDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
+func (fd *FileDiscovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	defer close(ch)
 	defer fd.stop()
 
@@ -123,11 +107,11 @@ func (fd *FileDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{})
 		// Stopping has priority over refreshing. Thus we wrap the actual select
 		// clause to always catch done signals.
 		select {
-		case <-done:
+		case <-ctx.Done():
 			return
 		default:
 			select {
-			case <-done:
+			case <-ctx.Done():
 				return
 
 			case event := <-fd.watcher.Events:
@@ -188,7 +172,7 @@ func (fd *FileDiscovery) stop() {
 
 // refresh reads all files matching the discovery's patterns and sends the respective
 // updated target groups through the channel.
-func (fd *FileDiscovery) refresh(ch chan<- config.TargetGroup) {
+func (fd *FileDiscovery) refresh(ch chan<- []*config.TargetGroup) {
 	ref := map[string]int{}
 	for _, p := range fd.listFiles() {
 		tgroups, err := readFile(p)
@@ -198,9 +182,8 @@ func (fd *FileDiscovery) refresh(ch chan<- config.TargetGroup) {
 			ref[p] = fd.lastRefresh[p]
 			continue
 		}
-		for _, tg := range tgroups {
-			ch <- *tg
-		}
+		ch <- tgroups
+
 		ref[p] = len(tgroups)
 	}
 	// Send empty updates for sources that disappeared.
@@ -208,7 +191,9 @@ func (fd *FileDiscovery) refresh(ch chan<- config.TargetGroup) {
 		m, ok := ref[f]
 		if !ok || n > m {
 			for i := m; i < n; i++ {
-				ch <- config.TargetGroup{Source: fileSource(f, i)}
+				ch <- []*config.TargetGroup{
+					{Source: fileSource(f, i)},
+				}
 			}
 		}
 	}

retrieval/discovery/file_test.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
 
 	"github.com/prometheus/prometheus/config"
 )
@@ -27,17 +28,17 @@ func testFileSD(t *testing.T, ext string) {
 	conf.RefreshInterval = model.Duration(1 * time.Hour)
 
 	var (
-		fsd  = NewFileDiscovery(&conf)
-		ch   = make(chan config.TargetGroup)
-		done = make(chan struct{})
+		fsd         = NewFileDiscovery(&conf)
+		ch          = make(chan []*config.TargetGroup)
+		ctx, cancel = context.WithCancel(context.Background())
 	)
-	go fsd.Run(ch, done)
+	go fsd.Run(ctx, ch)
 
 	select {
 	case <-time.After(25 * time.Millisecond):
 		// Expected.
-	case tg := <-ch:
-		t.Fatalf("Unexpected target group in file discovery: %s", tg)
+	case tgs := <-ch:
+		t.Fatalf("Unexpected target groups in file discovery: %s", tgs)
 	}
 
 	newf, err := os.Create("fixtures/_test" + ext)
@@ -58,37 +59,45 @@ func testFileSD(t *testing.T, ext string) {
 	}
 	newf.Close()
 
-	// The files contain two target groups which are read and sent in order.
-	select {
-	case <-time.After(15 * time.Second):
-		t.Fatalf("Expected new target group but got none")
-	case tg := <-ch:
-		if _, ok := tg.Labels["foo"]; !ok {
-			t.Fatalf("Label not parsed")
-		}
-		if tg.String() != fmt.Sprintf("fixtures/_test%s:0", ext) {
-			t.Fatalf("Unexpected target group %s", tg)
-		}
-	}
-	select {
-	case <-time.After(15 * time.Second):
-		t.Fatalf("Expected new target group but got none")
-	case tg := <-ch:
-		if tg.String() != fmt.Sprintf("fixtures/_test%s:1", ext) {
-			t.Fatalf("Unexpected target group %s", tg)
+	timeout := time.After(15 * time.Second)
+	// The files contain two target groups.
+retry:
+	for {
+		select {
+		case <-timeout:
+			t.Fatalf("Expected new target group but got none")
+		case tgs := <-ch:
+			if len(tgs) != 2 {
+				continue retry // Potentially a partial write, just retry.
+			}
+			tg := tgs[0]
+
+			if _, ok := tg.Labels["foo"]; !ok {
+				t.Fatalf("Label not parsed")
+			}
+			if tg.String() != fmt.Sprintf("fixtures/_test%s:0", ext) {
+				t.Fatalf("Unexpected target group %s", tg)
+			}
+
+			tg = tgs[1]
+			if tg.String() != fmt.Sprintf("fixtures/_test%s:1", ext) {
+				t.Fatalf("Unexpected target groups %s", tg)
+			}
+			break retry
 		}
 	}
+
 	// Based on unknown circumstances, sometimes fsnotify will trigger more events in
 	// some runs (which might be empty, chains of different operations etc.).
 	// We have to drain those (as the target manager would) to avoid deadlocking and must
 	// not try to make sense of it all...
 	drained := make(chan struct{})
 	go func() {
-		for tg := range ch {
+		for tgs := range ch {
 			// Below we will change the file to a bad syntax. Previously extracted target
 			// groups must not be deleted via sending an empty target group.
-			if len(tg.Targets) == 0 {
-				t.Errorf("Unexpected empty target group received: %s", tg)
+			if len(tgs[0].Targets) == 0 {
+				t.Errorf("Unexpected empty target groups received: %s", tgs)
 			}
 		}
 		close(drained)
@@ -107,6 +116,6 @@ func testFileSD(t *testing.T, ext string) {
 
 	os.Rename(newf.Name(), "fixtures/_test"+ext)
 
-	close(done)
+	cancel()
 	<-drained
 }

retrieval/discovery/kubernetes/discovery.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
 
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/util/httputil"
@@ -94,75 +95,35 @@ func (kd *Discovery) Initialize() error {
 	return nil
 }
 
-// Sources implements the TargetProvider interface.
-func (kd *Discovery) Sources() []string {
-	sourceNames := make([]string, 0, len(kd.apiServers))
-	for _, apiServer := range kd.apiServers {
-		sourceNames = append(sourceNames, apiServersTargetGroupName+":"+apiServer.Host)
-	}
-
-	nodes, _, err := kd.getNodes()
-	if err != nil {
-		// If we can't list nodes then we can't watch them. Assume this is a misconfiguration
-		// & log & return empty.
-		log.Errorf("Unable to initialize Kubernetes nodes: %s", err)
-		return []string{}
-	}
-	sourceNames = append(sourceNames, kd.nodeSources(nodes)...)
-
-	services, _, err := kd.getServices()
-	if err != nil {
-		// If we can't list services then we can't watch them. Assume this is a misconfiguration
-		// & log & return empty.
-		log.Errorf("Unable to initialize Kubernetes services: %s", err)
-		return []string{}
-	}
-	sourceNames = append(sourceNames, kd.serviceSources(services)...)
-
-	return sourceNames
-}
-
-func (kd *Discovery) nodeSources(nodes map[string]*Node) []string {
-	var sourceNames []string
-	for name := range nodes {
-		sourceNames = append(sourceNames, nodesTargetGroupName+":"+name)
-	}
-	return sourceNames
-}
-
-func (kd *Discovery) serviceSources(services map[string]map[string]*Service) []string {
-	var sourceNames []string
-	for _, ns := range services {
-		for _, service := range ns {
-			sourceNames = append(sourceNames, serviceSource(service))
-		}
-	}
-	return sourceNames
-}
-
 // Run implements the TargetProvider interface.
-func (kd *Discovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
+func (kd *Discovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	defer close(ch)
 
-	if tg := kd.updateAPIServersTargetGroup(); tg != nil {
-		select {
-		case ch <- *tg:
-		case <-done:
-			return
-		}
+	// Send an initial full view.
+	// TODO(fabxc): this does not include all available services and service
+	// endpoints yet. Service endpoints were also missing in the previous Sources() method.
+	var all []*config.TargetGroup
+
+	all = append(all, kd.updateAPIServersTargetGroup())
+	all = append(all, kd.updateNodesTargetGroup())
+
+	select {
+	case ch <- all:
+	case <-ctx.Done():
+		return
 	}
 
 	retryInterval := time.Duration(kd.Conf.RetryInterval)
 
 	update := make(chan interface{}, 10)
 
-	go kd.watchNodes(update, done, retryInterval)
-	go kd.startServiceWatch(update, done, retryInterval)
+	go kd.watchNodes(update, ctx.Done(), retryInterval)
+	go kd.startServiceWatch(update, ctx.Done(), retryInterval)
 
 	var tg *config.TargetGroup
 	for {
 		select {
-		case <-done:
+		case <-ctx.Done():
 			return
 		case event := <-update:
 			switch obj := event.(type) {
@@ -181,8 +142,8 @@ func (kd *Discovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
 		}
 
 		select {
-		case ch <- *tg:
-		case <-done:
+		case ch <- []*config.TargetGroup{tg}:
+		case <-ctx.Done():
 			return
 		}
 	}
@@ -265,7 +226,13 @@ func (kd *Discovery) updateNodesTargetGroup() *config.TargetGroup {
 
 	// Now let's loop through the nodes & add them to the target group with appropriate labels.
 	for nodeName, node := range kd.nodes {
-		address := fmt.Sprintf("%s:%d", node.Status.Addresses[0].Address, kd.Conf.KubeletPort)
+		nodeAddress, err := nodeHostIP(node)
+		if err != nil {
+			log.Debugf("Skipping node %s: %s", node.Name, err)
+			continue
+		}
+
+		address := fmt.Sprintf("%s:%d", nodeAddress.String(), kd.Conf.KubeletPort)
 
 		t := model.LabelSet{
 			model.AddressLabel:  model.LabelValue(address),
@@ -744,3 +711,27 @@ func until(f func(), period time.Duration, stopCh <-chan struct{}) {
 		}
 	}
 }
+
+// nodeHostIP returns the provided node's address, based on the priority:
+// 1. NodeInternalIP
+// 2. NodeExternalIP
+// 3. NodeLegacyHostIP
+//
+// Copied from k8s.io/kubernetes/pkg/util/node/node.go
+func nodeHostIP(node *Node) (net.IP, error) {
+	addresses := node.Status.Addresses
+	addressMap := make(map[NodeAddressType][]NodeAddress)
+	for i := range addresses {
+		addressMap[addresses[i].Type] = append(addressMap[addresses[i].Type], addresses[i])
+	}
+	if addresses, ok := addressMap[NodeInternalIP]; ok {
+		return net.ParseIP(addresses[0].Address), nil
+	}
+	if addresses, ok := addressMap[NodeExternalIP]; ok {
+		return net.ParseIP(addresses[0].Address), nil
+	}
+	if addresses, ok := addressMap[NodeLegacyHostIP]; ok {
+		return net.ParseIP(addresses[0].Address), nil
+	}
+	return nil, fmt.Errorf("host IP unknown; known addresses: %v", addresses)
+}

retrieval/discovery/kubernetes/types.go

@@ -202,11 +202,13 @@ type NodeStatus struct {
 
 type NodeAddressType string
 
-// These are valid address type of node.
+// These are valid address types of node. NodeLegacyHostIP is used to transit
+// from out-dated HostIP field to NodeAddress.
 const (
-	NodeHostName   NodeAddressType = "Hostname"
-	NodeExternalIP NodeAddressType = "ExternalIP"
-	NodeInternalIP NodeAddressType = "InternalIP"
+	NodeLegacyHostIP NodeAddressType = "LegacyHostIP"
+	NodeHostName     NodeAddressType = "Hostname"
+	NodeExternalIP   NodeAddressType = "ExternalIP"
+	NodeInternalIP   NodeAddressType = "InternalIP"
 )
 
 type NodeAddress struct {

retrieval/discovery/marathon.go

@@ -17,6 +17,8 @@ import (
 	"time"
 
 	"github.com/prometheus/common/log"
+	"golang.org/x/net/context"
+
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/retrieval/discovery/marathon"
 )
@@ -40,25 +42,13 @@ func NewMarathonDiscovery(conf *config.MarathonSDConfig) *MarathonDiscovery {
 	}
 }
 
-// Sources implements the TargetProvider interface.
-func (md *MarathonDiscovery) Sources() []string {
-	var sources []string
-	tgroups, err := md.fetchTargetGroups()
-	if err == nil {
-		for source := range tgroups {
-			sources = append(sources, source)
-		}
-	}
-	return sources
-}
-
 // Run implements the TargetProvider interface.
-func (md *MarathonDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
+func (md *MarathonDiscovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	defer close(ch)
 
 	for {
 		select {
-		case <-done:
+		case <-ctx.Done():
 			return
 		case <-time.After(md.refreshInterval):
 			err := md.updateServices(ch)
@@ -69,23 +59,24 @@ func (md *MarathonDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struc
 	}
 }
 
-func (md *MarathonDiscovery) updateServices(ch chan<- config.TargetGroup) error {
+func (md *MarathonDiscovery) updateServices(ch chan<- []*config.TargetGroup) error {
 	targetMap, err := md.fetchTargetGroups()
 	if err != nil {
 		return err
 	}
 
-	// Update services which are still present
+	all := make([]*config.TargetGroup, 0, len(targetMap))
 	for _, tg := range targetMap {
-		ch <- *tg
+		all = append(all, tg)
 	}
+	ch <- all
 
 	// Remove services which did disappear
 	for source := range md.lastRefresh {
 		_, ok := targetMap[source]
 		if !ok {
 			log.Debugf("Removing group for %s", source)
-			ch <- config.TargetGroup{Source: source}
+			ch <- []*config.TargetGroup{{Source: source}}
 		}
 	}
 

retrieval/discovery/marathon_test.go

@@ -19,6 +19,7 @@ import (
 	"time"
 
 	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
 
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/retrieval/discovery/marathon"
@@ -26,8 +27,8 @@ import (
 
 var marathonValidLabel = map[string]string{"prometheus": "yes"}
 
-func newTestDiscovery(client marathon.AppListClient) (chan config.TargetGroup, *MarathonDiscovery) {
-	ch := make(chan config.TargetGroup)
+func newTestDiscovery(client marathon.AppListClient) (chan []*config.TargetGroup, *MarathonDiscovery) {
+	ch := make(chan []*config.TargetGroup)
 	md := NewMarathonDiscovery(&config.MarathonSDConfig{
 		Servers: []string{"http://localhost:8080"},
 	})
@@ -60,7 +61,9 @@ func TestMarathonSDEmptyList(t *testing.T) {
 	go func() {
 		select {
 		case tg := <-ch:
-			t.Fatalf("Got group: %v", tg)
+			if len(tg) > 0 {
+				t.Fatalf("Got group: %v", tg)
+			}
 		default:
 		}
 	}()
@@ -96,7 +99,9 @@ func TestMarathonSDSendGroup(t *testing.T) {
 	})
 	go func() {
 		select {
-		case tg := <-ch:
+		case tgs := <-ch:
+			tg := tgs[0]
+
 			if tg.Source != "test-service" {
 				t.Fatalf("Wrong target group name: %s", tg.Source)
 			}
@@ -121,9 +126,10 @@ func TestMarathonSDRemoveApp(t *testing.T) {
 	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
 		return marathonTestAppList(marathonValidLabel, 1), nil
 	})
+
 	go func() {
-		up1 := <-ch
-		up2 := <-ch
+		up1 := (<-ch)[0]
+		up2 := (<-ch)[0]
 		if up2.Source != up1.Source {
 			t.Fatalf("Source is different: %s", up2)
 			if len(up2.Targets) > 0 {
@@ -145,33 +151,25 @@ func TestMarathonSDRemoveApp(t *testing.T) {
 	}
 }
 
-func TestMarathonSDSources(t *testing.T) {
-	_, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
-		return marathonTestAppList(marathonValidLabel, 1), nil
-	})
-	sources := md.Sources()
-	if len(sources) != 1 {
-		t.Fatalf("Wrong number of sources: %s", sources)
-	}
-}
-
 func TestMarathonSDRunAndStop(t *testing.T) {
 	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
 		return marathonTestAppList(marathonValidLabel, 1), nil
 	})
 	md.refreshInterval = time.Millisecond * 10
-	done := make(chan struct{})
+	ctx, cancel := context.WithCancel(context.Background())
 
 	go func() {
 		select {
 		case <-ch:
-			close(done)
+			cancel()
 		case <-time.After(md.refreshInterval * 3):
-			close(done)
+			cancel()
 			t.Fatalf("Update took too long.")
 		}
 	}()
-	md.Run(ch, done)
+
+	md.Run(ctx, ch)
+
 	select {
 	case <-ch:
 	default:

retrieval/discovery/nerve.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/prometheus/common/model"
 	"github.com/samuel/go-zookeeper/zk"
+	"golang.org/x/net/context"
 
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/util/treecache"
@@ -47,7 +48,7 @@ type NerveDiscovery struct {
 	conn       *zk.Conn
 	mu         sync.RWMutex
 	sources    map[string]*config.TargetGroup
-	sdUpdates  *chan<- config.TargetGroup
+	sdUpdates  *chan<- []*config.TargetGroup
 	updates    chan treecache.ZookeeperTreeCacheEvent
 	treeCaches []*treecache.ZookeeperTreeCache
 }
@@ -73,17 +74,6 @@ func NewNerveDiscovery(conf *config.NerveSDConfig) *NerveDiscovery {
 	return sd
 }
 
-// Sources implements the TargetProvider interface.
-func (sd *NerveDiscovery) Sources() []string {
-	sd.mu.RLock()
-	defer sd.mu.RUnlock()
-	srcs := []string{}
-	for t := range sd.sources {
-		srcs = append(srcs, t)
-	}
-	return srcs
-}
-
 func (sd *NerveDiscovery) processUpdates() {
 	defer sd.conn.Close()
 	for event := range sd.updates {
@@ -104,7 +94,7 @@ func (sd *NerveDiscovery) processUpdates() {
 		}
 		sd.mu.Unlock()
 		if sd.sdUpdates != nil {
-			*sd.sdUpdates <- *tg
+			*sd.sdUpdates <- []*config.TargetGroup{tg}
 		}
 	}
 
@@ -114,17 +104,22 @@ func (sd *NerveDiscovery) processUpdates() {
 }
 
 // Run implements the TargetProvider interface.
-func (sd *NerveDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
+func (sd *NerveDiscovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	// Send on everything we have seen so far.
 	sd.mu.Lock()
-	for _, targetGroup := range sd.sources {
-		ch <- *targetGroup
+
+	all := make([]*config.TargetGroup, 0, len(sd.sources))
+
+	for _, tg := range sd.sources {
+		all = append(all, tg)
 	}
+	ch <- all
+
 	// Tell processUpdates to send future updates.
 	sd.sdUpdates = &ch
 	sd.mu.Unlock()
 
-	<-done
+	<-ctx.Done()
 	for _, tc := range sd.treeCaches {
 		tc.Stop()
 	}

retrieval/discovery/serverset.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/prometheus/common/model"
 	"github.com/samuel/go-zookeeper/zk"
+	"golang.org/x/net/context"
 
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/util/strutil"
@@ -57,7 +58,7 @@ type ServersetDiscovery struct {
 	conn       *zk.Conn
 	mu         sync.RWMutex
 	sources    map[string]*config.TargetGroup
-	sdUpdates  *chan<- config.TargetGroup
+	sdUpdates  *chan<- []*config.TargetGroup
 	updates    chan treecache.ZookeeperTreeCacheEvent
 	treeCaches []*treecache.ZookeeperTreeCache
 }
@@ -83,17 +84,6 @@ func NewServersetDiscovery(conf *config.ServersetSDConfig) *ServersetDiscovery {
 	return sd
 }
 
-// Sources implements the TargetProvider interface.
-func (sd *ServersetDiscovery) Sources() []string {
-	sd.mu.RLock()
-	defer sd.mu.RUnlock()
-	srcs := []string{}
-	for t := range sd.sources {
-		srcs = append(srcs, t)
-	}
-	return srcs
-}
-
 func (sd *ServersetDiscovery) processUpdates() {
 	defer sd.conn.Close()
 	for event := range sd.updates {
@@ -114,7 +104,7 @@ func (sd *ServersetDiscovery) processUpdates() {
 		}
 		sd.mu.Unlock()
 		if sd.sdUpdates != nil {
-			*sd.sdUpdates <- *tg
+			*sd.sdUpdates <- []*config.TargetGroup{tg}
 		}
 	}
 
@@ -124,17 +114,22 @@ func (sd *ServersetDiscovery) processUpdates() {
 }
 
 // Run implements the TargetProvider interface.
-func (sd *ServersetDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
+func (sd *ServersetDiscovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	// Send on everything we have seen so far.
 	sd.mu.Lock()
-	for _, targetGroup := range sd.sources {
-		ch <- *targetGroup
+
+	all := make([]*config.TargetGroup, 0, len(sd.sources))
+
+	for _, tg := range sd.sources {
+		all = append(all, tg)
 	}
+	ch <- all
+
 	// Tell processUpdates to send future updates.
 	sd.sdUpdates = &ch
 	sd.mu.Unlock()
 
-	<-done
+	<-ctx.Done()
 	for _, tc := range sd.treeCaches {
 		tc.Stop()
 	}
@@ -142,8 +137,8 @@ func (sd *ServersetDiscovery) Run(ch chan<- config.TargetGroup, done <-chan stru
 
 func parseServersetMember(data []byte, path string) (*model.LabelSet, error) {
 	member := serversetMember{}
-	err := json.Unmarshal(data, &member)
-	if err != nil {
+
+	if err := json.Unmarshal(data, &member); err != nil {
 		return nil, fmt.Errorf("error unmarshaling serverset member %q: %s", path, err)
 	}
 

retrieval/scrape.go

@@ -0,0 +1,450 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package retrieval
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/expfmt"
+	"github.com/prometheus/common/log"
+	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
+	"golang.org/x/net/context/ctxhttp"
+
+	"github.com/prometheus/prometheus/config"
+	"github.com/prometheus/prometheus/storage"
+	"github.com/prometheus/prometheus/storage/local"
+)
+
+const (
+	scrapeHealthMetricName   = "up"
+	scrapeDurationMetricName = "scrape_duration_seconds"
+
+	// Capacity of the channel to buffer samples during ingestion.
+	ingestedSamplesCap = 256
+
+	// Constants for instrumentation.
+	namespace = "prometheus"
+	interval  = "interval"
+)
+
+var (
+	errSkippedScrape = errors.New("scrape skipped due to throttled ingestion")
+
+	targetIntervalLength = prometheus.NewSummaryVec(
+		prometheus.SummaryOpts{
+			Namespace:  namespace,
+			Name:       "target_interval_length_seconds",
+			Help:       "Actual intervals between scrapes.",
+			Objectives: map[float64]float64{0.01: 0.001, 0.05: 0.005, 0.5: 0.05, 0.90: 0.01, 0.99: 0.001},
+		},
+		[]string{interval},
+	)
+	targetSkippedScrapes = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: namespace,
+			Name:      "target_skipped_scrapes_total",
+			Help:      "Total number of scrapes that were skipped because the metric storage was throttled.",
+		},
+		[]string{interval},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(targetIntervalLength)
+	prometheus.MustRegister(targetSkippedScrapes)
+}
+
+// scrapePool manages scrapes for sets of targets.
+type scrapePool struct {
+	appender storage.SampleAppender
+
+	ctx context.Context
+
+	mtx    sync.RWMutex
+	config *config.ScrapeConfig
+	client *http.Client
+	// Targets and loops must always be synchronized to have the same
+	// set of hashes.
+	targets map[uint64]*Target
+	loops   map[uint64]loop
+
+	// Constructor for new scrape loops. This is settable for testing convenience.
+	newLoop func(context.Context, scraper, storage.SampleAppender, storage.SampleAppender) loop
+}
+
+func newScrapePool(cfg *config.ScrapeConfig, app storage.SampleAppender) *scrapePool {
+	client, err := newHTTPClient(cfg)
+	if err != nil {
+		// Any errors that could occur here should be caught during config validation.
+		log.Errorf("Error creating HTTP client for job %q: %s", cfg.JobName, err)
+	}
+	return &scrapePool{
+		appender: app,
+		config:   cfg,
+		client:   client,
+		targets:  map[uint64]*Target{},
+		loops:    map[uint64]loop{},
+		newLoop:  newScrapeLoop,
+	}
+}
+
+// stop terminates all scrape loops and returns after they all terminated.
+func (sp *scrapePool) stop() {
+	var wg sync.WaitGroup
+
+	sp.mtx.Lock()
+	defer sp.mtx.Unlock()
+
+	for fp, l := range sp.loops {
+		wg.Add(1)
+
+		go func(l loop) {
+			l.stop()
+			wg.Done()
+		}(l)
+
+		delete(sp.loops, fp)
+		delete(sp.targets, fp)
+	}
+
+	wg.Wait()
+}
+
+// reload the scrape pool with the given scrape configuration. The target state is preserved
+// but all scrape loops are restarted with the new scrape configuration.
+// This method returns after all scrape loops that were stopped have fully terminated.
+func (sp *scrapePool) reload(cfg *config.ScrapeConfig) {
+	sp.mtx.Lock()
+	defer sp.mtx.Unlock()
+
+	client, err := newHTTPClient(cfg)
+	if err != nil {
+		// Any errors that could occur here should be caught during config validation.
+		log.Errorf("Error creating HTTP client for job %q: %s", cfg.JobName, err)
+	}
+	sp.config = cfg
+	sp.client = client
+
+	var (
+		wg       sync.WaitGroup
+		interval = time.Duration(sp.config.ScrapeInterval)
+		timeout  = time.Duration(sp.config.ScrapeTimeout)
+	)
+
+	for fp, oldLoop := range sp.loops {
+		var (
+			t       = sp.targets[fp]
+			s       = &targetScraper{Target: t, client: sp.client}
+			newLoop = sp.newLoop(sp.ctx, s, sp.sampleAppender(t), sp.reportAppender(t))
+		)
+		wg.Add(1)
+
+		go func(oldLoop, newLoop loop) {
+			oldLoop.stop()
+			wg.Done()
+
+			go newLoop.run(interval, timeout, nil)
+		}(oldLoop, newLoop)
+
+		sp.loops[fp] = newLoop
+	}
+
+	wg.Wait()
+}
+
+// sync takes a list of potentially duplicated targets, deduplicates them, starts
+// scrape loops for new targets, and stops scrape loops for disappeared targets.
+// It returns after all stopped scrape loops terminated.
+func (sp *scrapePool) sync(targets []*Target) {
+	sp.mtx.Lock()
+	defer sp.mtx.Unlock()
+
+	var (
+		uniqueTargets = map[uint64]struct{}{}
+		interval      = time.Duration(sp.config.ScrapeInterval)
+		timeout       = time.Duration(sp.config.ScrapeTimeout)
+	)
+
+	for _, t := range targets {
+		hash := t.hash()
+		uniqueTargets[hash] = struct{}{}
+
+		if _, ok := sp.targets[hash]; !ok {
+			s := &targetScraper{Target: t, client: sp.client}
+			l := sp.newLoop(sp.ctx, s, sp.sampleAppender(t), sp.reportAppender(t))
+
+			sp.targets[hash] = t
+			sp.loops[hash] = l
+
+			go l.run(interval, timeout, nil)
+		}
+	}
+
+	var wg sync.WaitGroup
+
+	// Stop and remove old targets and scraper loops.
+	for hash := range sp.targets {
+		if _, ok := uniqueTargets[hash]; !ok {
+			wg.Add(1)
+			go func(l loop) {
+				l.stop()
+				wg.Done()
+			}(sp.loops[hash])
+
+			delete(sp.loops, hash)
+			delete(sp.targets, hash)
+		}
+	}
+
+	// Wait for all potentially stopped scrapers to terminate.
+	// This covers the case of flapping targets. If the server is under high load, a new scraper
+	// may be active and tries to insert. The old scraper that didn't terminate yet could still
+	// be inserting a previous sample set.
+	wg.Wait()
+}
+
+// sampleAppender returns an appender for ingested samples from the target.
+func (sp *scrapePool) sampleAppender(target *Target) storage.SampleAppender {
+	app := sp.appender
+	// The relabelAppender has to be inside the label-modifying appenders
+	// so the relabeling rules are applied to the correct label set.
+	if mrc := sp.config.MetricRelabelConfigs; len(mrc) > 0 {
+		app = relabelAppender{
+			SampleAppender: app,
+			relabelings:    mrc,
+		}
+	}
+
+	if sp.config.HonorLabels {
+		app = honorLabelsAppender{
+			SampleAppender: app,
+			labels:         target.Labels(),
+		}
+	} else {
+		app = ruleLabelsAppender{
+			SampleAppender: app,
+			labels:         target.Labels(),
+		}
+	}
+	return app
+}
+
+// reportAppender returns an appender for reporting samples for the target.
+func (sp *scrapePool) reportAppender(target *Target) storage.SampleAppender {
+	return ruleLabelsAppender{
+		SampleAppender: sp.appender,
+		labels:         target.Labels(),
+	}
+}
+
+// A scraper retrieves samples and accepts a status report at the end.
+type scraper interface {
+	scrape(ctx context.Context, ts time.Time) (model.Samples, error)
+	report(start time.Time, dur time.Duration, err error)
+	offset(interval time.Duration) time.Duration
+}
+
+// targetScraper implements the scraper interface for a target.
+type targetScraper struct {
+	*Target
+	client *http.Client
+}
+
+const acceptHeader = `application/vnd.google.protobuf;proto=io.prometheus.client.MetricFamily;encoding=delimited;q=0.7,text/plain;version=0.0.4;q=0.3,application/json;schema="prometheus/telemetry";version=0.0.2;q=0.2,*/*;q=0.1`
+
+func (s *targetScraper) scrape(ctx context.Context, ts time.Time) (model.Samples, error) {
+	req, err := http.NewRequest("GET", s.URL().String(), nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Add("Accept", acceptHeader)
+
+	resp, err := ctxhttp.Do(ctx, s.client, req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("server returned HTTP status %s", resp.Status)
+	}
+
+	var (
+		allSamples = make(model.Samples, 0, 200)
+		decSamples = make(model.Vector, 0, 50)
+	)
+	sdec := expfmt.SampleDecoder{
+		Dec: expfmt.NewDecoder(resp.Body, expfmt.ResponseFormat(resp.Header)),
+		Opts: &expfmt.DecodeOptions{
+			Timestamp: model.TimeFromUnixNano(ts.UnixNano()),
+		},
+	}
+
+	for {
+		if err = sdec.Decode(&decSamples); err != nil {
+			break
+		}
+		allSamples = append(allSamples, decSamples...)
+		decSamples = decSamples[:0]
+	}
+
+	if err == io.EOF {
+		// Set err to nil since it is used in the scrape health recording.
+		err = nil
+	}
+	return allSamples, err
+}
+
+// A loop can run and be stopped again. It must not be reused after it was stopped.
+type loop interface {
+	run(interval, timeout time.Duration, errc chan<- error)
+	stop()
+}
+
+type scrapeLoop struct {
+	scraper scraper
+
+	appender       storage.SampleAppender
+	reportAppender storage.SampleAppender
+
+	done   chan struct{}
+	ctx    context.Context
+	cancel func()
+}
+
+func newScrapeLoop(ctx context.Context, sc scraper, app, reportApp storage.SampleAppender) loop {
+	sl := &scrapeLoop{
+		scraper:        sc,
+		appender:       app,
+		reportAppender: reportApp,
+		done:           make(chan struct{}),
+	}
+	sl.ctx, sl.cancel = context.WithCancel(ctx)
+
+	return sl
+}
+
+func (sl *scrapeLoop) run(interval, timeout time.Duration, errc chan<- error) {
+	defer close(sl.done)
+
+	select {
+	case <-time.After(sl.scraper.offset(interval)):
+		// Continue after a scraping offset.
+	case <-sl.ctx.Done():
+		return
+	}
+
+	var last time.Time
+
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-sl.ctx.Done():
+			return
+		default:
+		}
+
+		if !sl.appender.NeedsThrottling() {
+			var (
+				start        = time.Now()
+				scrapeCtx, _ = context.WithTimeout(sl.ctx, timeout)
+			)
+
+			// Only record after the first scrape.
+			if !last.IsZero() {
+				targetIntervalLength.WithLabelValues(interval.String()).Observe(
+					float64(time.Since(last)) / float64(time.Second), // Sub-second precision.
+				)
+			}
+
+			samples, err := sl.scraper.scrape(scrapeCtx, start)
+			if err == nil {
+				sl.append(samples)
+			} else if errc != nil {
+				errc <- err
+			}
+
+			sl.report(start, time.Since(start), err)
+			last = start
+		} else {
+			targetSkippedScrapes.WithLabelValues(interval.String()).Inc()
+		}
+
+		select {
+		case <-sl.ctx.Done():
+			return
+		case <-ticker.C:
+		}
+	}
+}
+
+func (sl *scrapeLoop) stop() {
+	sl.cancel()
+	<-sl.done
+}
+
+func (sl *scrapeLoop) append(samples model.Samples) {
+	numOutOfOrder := 0
+
+	for _, s := range samples {
+		if err := sl.appender.Append(s); err != nil {
+			if err == local.ErrOutOfOrderSample {
+				numOutOfOrder++
+			} else {
+				log.Warnf("Error inserting sample: %s", err)
+			}
+		}
+	}
+	if numOutOfOrder > 0 {
+		log.With("numDropped", numOutOfOrder).Warn("Error on ingesting out-of-order samples")
+	}
+}
+
+func (sl *scrapeLoop) report(start time.Time, duration time.Duration, err error) {
+	sl.scraper.report(start, duration, err)
+
+	ts := model.TimeFromUnixNano(start.UnixNano())
+
+	var health model.SampleValue
+	if err == nil {
+		health = 1
+	}
+
+	healthSample := &model.Sample{
+		Metric: model.Metric{
+			model.MetricNameLabel: scrapeHealthMetricName,
+		},
+		Timestamp: ts,
+		Value:     health,
+	}
+	durationSample := &model.Sample{
+		Metric: model.Metric{
+			model.MetricNameLabel: scrapeDurationMetricName,
+		},
+		Timestamp: ts,
+		Value:     model.SampleValue(float64(duration) / float64(time.Second)),
+	}
+
+	sl.reportAppender.Append(healthSample)
+	sl.reportAppender.Append(durationSample)
+}

retrieval/scrape_test.go

@@ -0,0 +1,587 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package retrieval
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"reflect"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
+
+	"github.com/prometheus/prometheus/config"
+	"github.com/prometheus/prometheus/storage"
+)
+
+func TestNewScrapePool(t *testing.T) {
+	var (
+		app = &nopAppender{}
+		cfg = &config.ScrapeConfig{}
+		sp  = newScrapePool(cfg, app)
+	)
+
+	if a, ok := sp.appender.(*nopAppender); !ok || a != app {
+		t.Fatalf("Wrong sample appender")
+	}
+	if sp.config != cfg {
+		t.Fatalf("Wrong scrape config")
+	}
+	if sp.newLoop == nil {
+		t.Fatalf("newLoop function not initialized")
+	}
+}
+
+type testLoop struct {
+	startFunc func(interval, timeout time.Duration, errc chan<- error)
+	stopFunc  func()
+}
+
+func (l *testLoop) run(interval, timeout time.Duration, errc chan<- error) {
+	l.startFunc(interval, timeout, errc)
+}
+
+func (l *testLoop) stop() {
+	l.stopFunc()
+}
+
+func TestScrapePoolStop(t *testing.T) {
+	sp := &scrapePool{
+		targets: map[uint64]*Target{},
+		loops:   map[uint64]loop{},
+	}
+	var mtx sync.Mutex
+	stopped := map[uint64]bool{}
+	numTargets := 20
+
+	// Stopping the scrape pool must call stop() on all scrape loops,
+	// clean them and the respective targets up. It must wait until each loop's
+	// stop function returned before returning itself.
+
+	for i := 0; i < numTargets; i++ {
+		t := &Target{
+			labels: model.LabelSet{
+				model.AddressLabel: model.LabelValue(fmt.Sprintf("example.com:%d", i)),
+			},
+		}
+		l := &testLoop{}
+		l.stopFunc = func() {
+			time.Sleep(time.Duration(i*20) * time.Millisecond)
+
+			mtx.Lock()
+			stopped[t.hash()] = true
+			mtx.Unlock()
+		}
+
+		sp.targets[t.hash()] = t
+		sp.loops[t.hash()] = l
+	}
+
+	done := make(chan struct{})
+	stopTime := time.Now()
+
+	go func() {
+		sp.stop()
+		close(done)
+	}()
+
+	select {
+	case <-time.After(5 * time.Second):
+		t.Fatalf("scrapeLoop.stop() did not return as expected")
+	case <-done:
+		// This should have taken at least as long as the last target slept.
+		if time.Since(stopTime) < time.Duration(numTargets*20)*time.Millisecond {
+			t.Fatalf("scrapeLoop.stop() exited before all targets stopped")
+		}
+	}
+
+	mtx.Lock()
+	if len(stopped) != numTargets {
+		t.Fatalf("Expected 20 stopped loops, got %d", len(stopped))
+	}
+	mtx.Unlock()
+
+	if len(sp.targets) > 0 {
+		t.Fatalf("Targets were not cleared on stopping: %d left", len(sp.targets))
+	}
+	if len(sp.loops) > 0 {
+		t.Fatalf("Loops were not cleared on stopping: %d left", len(sp.loops))
+	}
+}
+
+func TestScrapePoolReload(t *testing.T) {
+	var mtx sync.Mutex
+	numTargets := 20
+
+	stopped := map[uint64]bool{}
+
+	reloadCfg := &config.ScrapeConfig{
+		ScrapeInterval: model.Duration(3 * time.Second),
+		ScrapeTimeout:  model.Duration(2 * time.Second),
+	}
+	// On starting to run, new loops created on reload check whether their preceeding
+	// equivalents have been stopped.
+	newLoop := func(ctx context.Context, s scraper, app, reportApp storage.SampleAppender) loop {
+		l := &testLoop{}
+		l.startFunc = func(interval, timeout time.Duration, errc chan<- error) {
+			if interval != 3*time.Second {
+				t.Errorf("Expected scrape interval %d but got %d", 3*time.Second, interval)
+			}
+			if timeout != 2*time.Second {
+				t.Errorf("Expected scrape timeout %d but got %d", 2*time.Second, timeout)
+			}
+			mtx.Lock()
+			if !stopped[s.(*targetScraper).hash()] {
+				t.Errorf("Scrape loop for %v not stopped yet", s.(*targetScraper))
+			}
+			mtx.Unlock()
+		}
+		return l
+	}
+	sp := &scrapePool{
+		targets: map[uint64]*Target{},
+		loops:   map[uint64]loop{},
+		newLoop: newLoop,
+	}
+
+	// Reloading a scrape pool with a new scrape configuration must stop all scrape
+	// loops and start new ones. A new loop must not be started before the preceeding
+	// one terminated.
+
+	for i := 0; i < numTargets; i++ {
+		t := &Target{
+			labels: model.LabelSet{
+				model.AddressLabel: model.LabelValue(fmt.Sprintf("example.com:%d", i)),
+			},
+		}
+		l := &testLoop{}
+		l.stopFunc = func() {
+			time.Sleep(time.Duration(i*20) * time.Millisecond)
+
+			mtx.Lock()
+			stopped[t.hash()] = true
+			mtx.Unlock()
+		}
+
+		sp.targets[t.hash()] = t
+		sp.loops[t.hash()] = l
+	}
+	done := make(chan struct{})
+
+	beforeTargets := map[uint64]*Target{}
+	for h, t := range sp.targets {
+		beforeTargets[h] = t
+	}
+
+	reloadTime := time.Now()
+
+	go func() {
+		sp.reload(reloadCfg)
+		close(done)
+	}()
+
+	select {
+	case <-time.After(5 * time.Second):
+		t.Fatalf("scrapeLoop.reload() did not return as expected")
+	case <-done:
+		// This should have taken at least as long as the last target slept.
+		if time.Since(reloadTime) < time.Duration(numTargets*20)*time.Millisecond {
+			t.Fatalf("scrapeLoop.stop() exited before all targets stopped")
+		}
+	}
+
+	mtx.Lock()
+	if len(stopped) != numTargets {
+		t.Fatalf("Expected 20 stopped loops, got %d", stopped)
+	}
+	mtx.Unlock()
+
+	if !reflect.DeepEqual(sp.targets, beforeTargets) {
+		t.Fatalf("Reloading affected target states unexpectedly")
+	}
+	if len(sp.loops) != numTargets {
+		t.Fatalf("Expected %d loops after reload but got %d", numTargets, len(sp.loops))
+	}
+}
+
+func TestScrapePoolReportAppender(t *testing.T) {
+	cfg := &config.ScrapeConfig{
+		MetricRelabelConfigs: []*config.RelabelConfig{
+			{}, {}, {},
+		},
+	}
+	target := newTestTarget("example.com:80", 10*time.Millisecond, nil)
+	app := &nopAppender{}
+
+	sp := newScrapePool(cfg, app)
+
+	cfg.HonorLabels = false
+	wrapped := sp.reportAppender(target)
+
+	rl, ok := wrapped.(ruleLabelsAppender)
+	if !ok {
+		t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
+	}
+	if rl.SampleAppender != app {
+		t.Fatalf("Expected base appender but got %T", rl.SampleAppender)
+	}
+
+	cfg.HonorLabels = true
+	wrapped = sp.reportAppender(target)
+
+	hl, ok := wrapped.(ruleLabelsAppender)
+	if !ok {
+		t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
+	}
+	if hl.SampleAppender != app {
+		t.Fatalf("Expected base appender but got %T", hl.SampleAppender)
+	}
+}
+
+func TestScrapePoolSampleAppender(t *testing.T) {
+	cfg := &config.ScrapeConfig{
+		MetricRelabelConfigs: []*config.RelabelConfig{
+			{}, {}, {},
+		},
+	}
+
+	target := newTestTarget("example.com:80", 10*time.Millisecond, nil)
+	app := &nopAppender{}
+
+	sp := newScrapePool(cfg, app)
+
+	cfg.HonorLabels = false
+	wrapped := sp.sampleAppender(target)
+
+	rl, ok := wrapped.(ruleLabelsAppender)
+	if !ok {
+		t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
+	}
+	re, ok := rl.SampleAppender.(relabelAppender)
+	if !ok {
+		t.Fatalf("Expected relabelAppender but got %T", rl.SampleAppender)
+	}
+	if re.SampleAppender != app {
+		t.Fatalf("Expected base appender but got %T", re.SampleAppender)
+	}
+
+	cfg.HonorLabels = true
+	wrapped = sp.sampleAppender(target)
+
+	hl, ok := wrapped.(honorLabelsAppender)
+	if !ok {
+		t.Fatalf("Expected honorLabelsAppender but got %T", wrapped)
+	}
+	re, ok = hl.SampleAppender.(relabelAppender)
+	if !ok {
+		t.Fatalf("Expected relabelAppender but got %T", hl.SampleAppender)
+	}
+	if re.SampleAppender != app {
+		t.Fatalf("Expected base appender but got %T", re.SampleAppender)
+	}
+}
+
+func TestScrapeLoopStop(t *testing.T) {
+	scraper := &testScraper{}
+	sl := newScrapeLoop(context.Background(), scraper, nil, nil)
+
+	// The scrape pool synchronizes on stopping scrape loops. However, new scrape
+	// loops are syarted asynchronously. Thus it's possible, that a loop is stopped
+	// again before having started properly.
+	// Stopping not-yet-started loops must block until the run method was called and exited.
+	// The run method must exit immediately.
+
+	stopDone := make(chan struct{})
+	go func() {
+		sl.stop()
+		close(stopDone)
+	}()
+
+	select {
+	case <-stopDone:
+		t.Fatalf("Stopping terminated before run exited successfully")
+	case <-time.After(500 * time.Millisecond):
+	}
+
+	// Running the scrape loop must exit before calling the scraper even once.
+	scraper.scrapeFunc = func(context.Context, time.Time) (model.Samples, error) {
+		t.Fatalf("scraper was called for terminated scrape loop")
+		return nil, nil
+	}
+
+	runDone := make(chan struct{})
+	go func() {
+		sl.run(0, 0, nil)
+		close(runDone)
+	}()
+
+	select {
+	case <-runDone:
+	case <-time.After(1 * time.Second):
+		t.Fatalf("Running terminated scrape loop did not exit")
+	}
+
+	select {
+	case <-stopDone:
+	case <-time.After(1 * time.Second):
+		t.Fatalf("Stopping did not terminate after running exited")
+	}
+}
+
+func TestScrapeLoopRun(t *testing.T) {
+	var (
+		signal = make(chan struct{})
+		errc   = make(chan error)
+
+		scraper   = &testScraper{}
+		app       = &nopAppender{}
+		reportApp = &nopAppender{}
+	)
+	defer close(signal)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	sl := newScrapeLoop(ctx, scraper, app, reportApp)
+
+	// The loop must terminate during the initial offset if the context
+	// is canceled.
+	scraper.offsetDur = time.Hour
+
+	go func() {
+		sl.run(time.Second, time.Hour, errc)
+		signal <- struct{}{}
+	}()
+
+	// Wait to make sure we are actually waiting on the offset.
+	time.Sleep(1 * time.Second)
+
+	cancel()
+	select {
+	case <-signal:
+	case <-time.After(5 * time.Second):
+		t.Fatalf("Cancelation during initial offset failed")
+	case err := <-errc:
+		t.Fatalf("Unexpected error: %s", err)
+	}
+
+	// The provided timeout must cause cancelation of the context passed down to the
+	// scraper. The scraper has to respect the context.
+	scraper.offsetDur = 0
+
+	block := make(chan struct{})
+	scraper.scrapeFunc = func(ctx context.Context, ts time.Time) (model.Samples, error) {
+		select {
+		case <-block:
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		}
+		return nil, nil
+	}
+
+	ctx, cancel = context.WithCancel(context.Background())
+	sl = newScrapeLoop(ctx, scraper, app, reportApp)
+
+	go func() {
+		sl.run(time.Second, 100*time.Millisecond, errc)
+		signal <- struct{}{}
+	}()
+
+	select {
+	case err := <-errc:
+		if err != context.DeadlineExceeded {
+			t.Fatalf("Expected timeout error but got: %s", err)
+		}
+	case <-time.After(3 * time.Second):
+		t.Fatalf("Expected timeout error but got none")
+	}
+
+	// We already caught the timeout error and are certainly in the loop.
+	// Let the scrapes returns immediately to cause no further timeout errors
+	// and check whether canceling the parent context terminates the loop.
+	close(block)
+	cancel()
+
+	select {
+	case <-signal:
+		// Loop terminated as expected.
+	case err := <-errc:
+		t.Fatalf("Unexpected error: %s", err)
+	case <-time.After(3 * time.Second):
+		t.Fatalf("Loop did not terminate on context cancelation")
+	}
+}
+
+func TestTargetScraperScrapeOK(t *testing.T) {
+	server := httptest.NewServer(
+		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", `text/plain; version=0.0.4`)
+			w.Write([]byte("metric_a 1\nmetric_b 2\n"))
+		}),
+	)
+	defer server.Close()
+
+	serverURL, err := url.Parse(server.URL)
+	if err != nil {
+		panic(err)
+	}
+
+	ts := &targetScraper{
+		Target: &Target{
+			labels: model.LabelSet{
+				model.SchemeLabel:  model.LabelValue(serverURL.Scheme),
+				model.AddressLabel: model.LabelValue(serverURL.Host),
+			},
+		},
+		client: http.DefaultClient,
+	}
+	now := time.Now()
+
+	samples, err := ts.scrape(context.Background(), now)
+	if err != nil {
+		t.Fatalf("Unexpected scrape error: %s", err)
+	}
+
+	expectedSamples := model.Samples{
+		{
+			Metric:    model.Metric{"__name__": "metric_a"},
+			Timestamp: model.TimeFromUnixNano(now.UnixNano()),
+			Value:     1,
+		},
+		{
+			Metric:    model.Metric{"__name__": "metric_b"},
+			Timestamp: model.TimeFromUnixNano(now.UnixNano()),
+			Value:     2,
+		},
+	}
+
+	if !reflect.DeepEqual(samples, expectedSamples) {
+		t.Errorf("Scraped samples did not match served metrics")
+		t.Errorf("Expected: %v", expectedSamples)
+		t.Fatalf("Got: %v", samples)
+	}
+}
+
+func TestTargetScrapeScrapeCancel(t *testing.T) {
+	block := make(chan struct{})
+
+	server := httptest.NewServer(
+		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			<-block
+		}),
+	)
+	defer server.Close()
+
+	serverURL, err := url.Parse(server.URL)
+	if err != nil {
+		panic(err)
+	}
+
+	ts := &targetScraper{
+		Target: &Target{
+			labels: model.LabelSet{
+				model.SchemeLabel:  model.LabelValue(serverURL.Scheme),
+				model.AddressLabel: model.LabelValue(serverURL.Host),
+			},
+		},
+		client: http.DefaultClient,
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+
+	done := make(chan struct{})
+
+	go func() {
+		time.Sleep(1 * time.Second)
+		cancel()
+	}()
+
+	go func() {
+		if _, err := ts.scrape(ctx, time.Now()); err != context.Canceled {
+			t.Fatalf("Expected context cancelation error but got: %s", err)
+		}
+		close(done)
+	}()
+
+	select {
+	case <-time.After(5 * time.Second):
+		t.Fatalf("Scrape function did not return unexpectedly")
+	case <-done:
+	}
+	// If this is closed in a defer above the function the test server
+	// does not terminate and the test doens't complete.
+	close(block)
+}
+
+func TestTargetScrapeScrapeNotFound(t *testing.T) {
+	server := httptest.NewServer(
+		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusNotFound)
+		}),
+	)
+	defer server.Close()
+
+	serverURL, err := url.Parse(server.URL)
+	if err != nil {
+		panic(err)
+	}
+
+	ts := &targetScraper{
+		Target: &Target{
+			labels: model.LabelSet{
+				model.SchemeLabel:  model.LabelValue(serverURL.Scheme),
+				model.AddressLabel: model.LabelValue(serverURL.Host),
+			},
+		},
+		client: http.DefaultClient,
+	}
+
+	if _, err := ts.scrape(context.Background(), time.Now()); !strings.Contains(err.Error(), "404") {
+		t.Fatalf("Expected \"404 NotFound\" error but got: %s", err)
+	}
+}
+
+// testScraper implements the scraper interface and allows setting values
+// returned by its methods. It also allows setting a custom scrape function.
+type testScraper struct {
+	offsetDur time.Duration
+
+	lastStart    time.Time
+	lastDuration time.Duration
+	lastError    error
+
+	samples    model.Samples
+	scrapeErr  error
+	scrapeFunc func(context.Context, time.Time) (model.Samples, error)
+}
+
+func (ts *testScraper) offset(interval time.Duration) time.Duration {
+	return ts.offsetDur
+}
+
+func (ts *testScraper) report(start time.Time, duration time.Duration, err error) {
+	ts.lastStart = start
+	ts.lastDuration = duration
+	ts.lastError = err
+}
+
+func (ts *testScraper) scrape(ctx context.Context, t time.Time) (model.Samples, error) {
+	if ts.scrapeFunc != nil {
+		return ts.scrapeFunc(ctx, t)
+	}
+	return ts.samples, ts.scrapeErr
+}

retrieval/target.go

@@ -14,9 +14,8 @@
 package retrieval
 
 import (
-	"errors"
 	"fmt"
-	"io"
+	"hash/fnv"
 	"io/ioutil"
 	"net/http"
 	"net/url"
@@ -24,200 +23,46 @@ import (
 	"sync"
 	"time"
 
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/expfmt"
-	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
-	"golang.org/x/net/context"
-	"golang.org/x/net/context/ctxhttp"
 
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/storage"
-	"github.com/prometheus/prometheus/storage/local"
 	"github.com/prometheus/prometheus/util/httputil"
 )
 
-const (
-	scrapeHealthMetricName   = "up"
-	scrapeDurationMetricName = "scrape_duration_seconds"
-
-	// Capacity of the channel to buffer samples during ingestion.
-	ingestedSamplesCap = 256
-
-	// Constants for instrumentation.
-	namespace = "prometheus"
-	interval  = "interval"
-)
-
-var (
-	errSkippedScrape = errors.New("scrape skipped due to throttled ingestion")
-
-	targetIntervalLength = prometheus.NewSummaryVec(
-		prometheus.SummaryOpts{
-			Namespace:  namespace,
-			Name:       "target_interval_length_seconds",
-			Help:       "Actual intervals between scrapes.",
-			Objectives: map[float64]float64{0.01: 0.001, 0.05: 0.005, 0.5: 0.05, 0.90: 0.01, 0.99: 0.001},
-		},
-		[]string{interval},
-	)
-	targetSkippedScrapes = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Namespace: namespace,
-			Name:      "target_skipped_scrapes_total",
-			Help:      "Total number of scrapes that were skipped because the metric storage was throttled.",
-		},
-		[]string{interval},
-	)
-)
-
-func init() {
-	prometheus.MustRegister(targetIntervalLength)
-	prometheus.MustRegister(targetSkippedScrapes)
-}
-
 // TargetHealth describes the health state of a target.
-type TargetHealth int
-
-func (t TargetHealth) String() string {
-	switch t {
-	case HealthUnknown:
-		return "unknown"
-	case HealthGood:
-		return "up"
-	case HealthBad:
-		return "down"
-	}
-	panic("unknown state")
-}
-
-func (t TargetHealth) value() model.SampleValue {
-	if t == HealthGood {
-		return 1
-	}
-	return 0
-}
+type TargetHealth string
 
+// The possible health states of a target based on the last performed scrape.
 const (
-	// HealthUnknown is the state of a Target before it is first scraped.
-	HealthUnknown TargetHealth = iota
-	// HealthGood is the state of a Target that has been successfully scraped.
-	HealthGood
-	// HealthBad is the state of a Target that was scraped unsuccessfully.
-	HealthBad
+	HealthUnknown TargetHealth = "unknown"
+	HealthGood    TargetHealth = "up"
+	HealthBad     TargetHealth = "down"
 )
 
-// TargetStatus contains information about the current status of a scrape target.
-type TargetStatus struct {
-	lastError  error
-	lastScrape time.Time
-	health     TargetHealth
-
-	mu sync.RWMutex
-}
-
-// LastError returns the error encountered during the last scrape.
-func (ts *TargetStatus) LastError() error {
-	ts.mu.RLock()
-	defer ts.mu.RUnlock()
-
-	return ts.lastError
-}
-
-// LastScrape returns the time of the last scrape.
-func (ts *TargetStatus) LastScrape() time.Time {
-	ts.mu.RLock()
-	defer ts.mu.RUnlock()
-
-	return ts.lastScrape
-}
-
-// Health returns the last known health state of the target.
-func (ts *TargetStatus) Health() TargetHealth {
-	ts.mu.RLock()
-	defer ts.mu.RUnlock()
-
-	return ts.health
-}
-
-func (ts *TargetStatus) setLastScrape(t time.Time) {
-	ts.mu.Lock()
-	defer ts.mu.Unlock()
-
-	ts.lastScrape = t
-}
-
-func (ts *TargetStatus) setLastError(err error) {
-	ts.mu.Lock()
-	defer ts.mu.Unlock()
-
-	if err == nil {
-		ts.health = HealthGood
-	} else {
-		ts.health = HealthBad
-	}
-	ts.lastError = err
-}
-
 // Target refers to a singular HTTP or HTTPS endpoint.
 type Target struct {
-	// The status object for the target. It is only set once on initialization.
-	status *TargetStatus
-	// Closing scraperStopping signals that scraping should stop.
-	scraperStopping chan struct{}
-	// Closing scraperStopped signals that scraping has been stopped.
-	scraperStopped chan struct{}
-
-	// Mutex protects the members below.
-	sync.RWMutex
-
-	scrapeConfig *config.ScrapeConfig
-
 	// Labels before any processing.
 	metaLabels model.LabelSet
 	// Any labels that are added to this target and its metrics.
 	labels model.LabelSet
+	// Additional URL parmeters that are part of the target URL.
+	params url.Values
 
-	// The HTTP client used to scrape the target's endpoint.
-	httpClient *http.Client
+	mtx        sync.RWMutex
+	lastError  error
+	lastScrape time.Time
+	health     TargetHealth
 }
 
 // NewTarget creates a reasonably configured target for querying.
-func NewTarget(cfg *config.ScrapeConfig, labels, metaLabels model.LabelSet) (*Target, error) {
-	t := &Target{
-		status:          &TargetStatus{},
-		scraperStopping: make(chan struct{}),
-		scraperStopped:  make(chan struct{}),
+func NewTarget(labels, metaLabels model.LabelSet, params url.Values) *Target {
+	return &Target{
+		labels:     labels,
+		metaLabels: metaLabels,
+		params:     params,
+		health:     HealthUnknown,
 	}
-	err := t.Update(cfg, labels, metaLabels)
-	return t, err
-}
-
-// Status returns the status of the target.
-func (t *Target) Status() *TargetStatus {
-	return t.status
-}
-
-// Update overwrites settings in the target that are derived from the job config
-// it belongs to.
-func (t *Target) Update(cfg *config.ScrapeConfig, labels, metaLabels model.LabelSet) error {
-	t.Lock()
-
-	t.scrapeConfig = cfg
-	t.labels = labels
-	t.metaLabels = metaLabels
-
-	t.Unlock()
-
-	httpClient, err := t.client()
-	if err != nil {
-		return fmt.Errorf("cannot create HTTP client: %s", err)
-	}
-	t.Lock()
-	t.httpClient = httpClient
-	t.Unlock()
-
-	return nil
 }
 
 func newHTTPClient(cfg *config.ScrapeConfig) (*http.Client, error) {
@@ -265,15 +110,16 @@ func newHTTPClient(cfg *config.ScrapeConfig) (*http.Client, error) {
 }
 
 func (t *Target) String() string {
-	return t.host()
+	return t.URL().String()
 }
 
-// fingerprint returns an identifying hash for the target.
-func (t *Target) fingerprint() model.Fingerprint {
-	t.RLock()
-	defer t.RUnlock()
+// hash returns an identifying hash for the target.
+func (t *Target) hash() uint64 {
+	h := fnv.New64a()
+	h.Write([]byte(t.labels.Fingerprint().String()))
+	h.Write([]byte(t.URL().String()))
 
-	return t.labels.Fingerprint()
+	return h.Sum64()
 }
 
 // offset returns the time until the next scrape cycle for the target.
@@ -282,7 +128,7 @@ func (t *Target) offset(interval time.Duration) time.Duration {
 
 	var (
 		base   = now % int64(interval)
-		offset = uint64(t.fingerprint()) % uint64(interval)
+		offset = t.hash() % uint64(interval)
 		next   = base + int64(offset)
 	)
 
@@ -292,92 +138,27 @@ func (t *Target) offset(interval time.Duration) time.Duration {
 	return time.Duration(next)
 }
 
-func (t *Target) client() (*http.Client, error) {
-	t.RLock()
-	defer t.RUnlock()
-
-	return newHTTPClient(t.scrapeConfig)
-}
-
-func (t *Target) interval() time.Duration {
-	t.RLock()
-	defer t.RUnlock()
-
-	return time.Duration(t.scrapeConfig.ScrapeInterval)
-}
-
-func (t *Target) timeout() time.Duration {
-	t.RLock()
-	defer t.RUnlock()
-
-	return time.Duration(t.scrapeConfig.ScrapeTimeout)
-}
-
-func (t *Target) scheme() string {
-	t.RLock()
-	defer t.RUnlock()
-
-	return string(t.labels[model.SchemeLabel])
-}
-
-func (t *Target) host() string {
-	t.RLock()
-	defer t.RUnlock()
-
-	return string(t.labels[model.AddressLabel])
-}
-
-func (t *Target) path() string {
-	t.RLock()
-	defer t.RUnlock()
-
-	return string(t.labels[model.MetricsPathLabel])
-}
-
-// wrapAppender wraps a SampleAppender for samples ingested from the target.
-// RLock must be acquired by the caller.
-func (t *Target) wrapAppender(app storage.SampleAppender) storage.SampleAppender {
-	// The relabelAppender has to be inside the label-modifying appenders
-	// so the relabeling rules are applied to the correct label set.
-	if mrc := t.scrapeConfig.MetricRelabelConfigs; len(mrc) > 0 {
-		app = relabelAppender{
-			SampleAppender: app,
-			relabelings:    mrc,
+// Labels returns a copy of the set of all public labels of the target.
+func (t *Target) Labels() model.LabelSet {
+	lset := make(model.LabelSet, len(t.labels))
+	for ln, lv := range t.labels {
+		if !strings.HasPrefix(string(ln), model.ReservedLabelPrefix) {
+			lset[ln] = lv
 		}
 	}
-
-	if t.scrapeConfig.HonorLabels {
-		app = honorLabelsAppender{
-			SampleAppender: app,
-			labels:         t.unlockedLabels(),
-		}
-	} else {
-		app = ruleLabelsAppender{
-			SampleAppender: app,
-			labels:         t.unlockedLabels(),
-		}
-	}
-	return app
+	return lset
 }
 
-// wrapReportingAppender wraps an appender for target status report samples.
-// It ignores any relabeling rules set for the target.
-// RLock must not be acquired by the caller.
-func (t *Target) wrapReportingAppender(app storage.SampleAppender) storage.SampleAppender {
-	return ruleLabelsAppender{
-		SampleAppender: app,
-		labels:         t.Labels(),
-	}
+// MetaLabels returns a copy of the target's labels before any processing.
+func (t *Target) MetaLabels() model.LabelSet {
+	return t.metaLabels.Clone()
 }
 
 // URL returns a copy of the target's URL.
 func (t *Target) URL() *url.URL {
-	t.RLock()
-	defer t.RUnlock()
-
 	params := url.Values{}
 
-	for k, v := range t.scrapeConfig.Params {
+	for k, v := range t.params {
 		params[k] = make([]string, len(v))
 		copy(params[k], v)
 	}
@@ -402,191 +183,51 @@ func (t *Target) URL() *url.URL {
 	}
 }
 
-// InstanceIdentifier returns the identifier for the target.
-func (t *Target) InstanceIdentifier() string {
-	return t.host()
-}
+func (t *Target) report(start time.Time, dur time.Duration, err error) {
+	t.mtx.Lock()
+	defer t.mtx.Unlock()
 
-// RunScraper implements Target.
-func (t *Target) RunScraper(sampleAppender storage.SampleAppender) {
-	defer close(t.scraperStopped)
-
-	lastScrapeInterval := t.interval()
-
-	log.Debugf("Starting scraper for target %v...", t)
-
-	select {
-	case <-time.After(t.offset(lastScrapeInterval)):
-		// Continue after scraping offset.
-	case <-t.scraperStopping:
-		return
-	}
-
-	ticker := time.NewTicker(lastScrapeInterval)
-	defer ticker.Stop()
-
-	t.scrape(sampleAppender)
-
-	// Explanation of the contraption below:
-	//
-	// In case t.scraperStopping has something to receive, we want to read
-	// from that channel rather than starting a new scrape (which might take very
-	// long). That's why the outer select has no ticker.C. Should t.scraperStopping
-	// not have anything to receive, we go into the inner select, where ticker.C
-	// is in the mix.
-	for {
-		select {
-		case <-t.scraperStopping:
-			return
-		default:
-			select {
-			case <-t.scraperStopping:
-				return
-			case <-ticker.C:
-				took := time.Since(t.status.LastScrape())
-
-				intervalStr := lastScrapeInterval.String()
-
-				// On changed scrape interval the new interval becomes effective
-				// after the next scrape.
-				if iv := t.interval(); iv != lastScrapeInterval {
-					ticker.Stop()
-					ticker = time.NewTicker(iv)
-					lastScrapeInterval = iv
-				}
-
-				targetIntervalLength.WithLabelValues(intervalStr).Observe(
-					float64(took) / float64(time.Second), // Sub-second precision.
-				)
-				if sampleAppender.NeedsThrottling() {
-					targetSkippedScrapes.WithLabelValues(intervalStr).Inc()
-					t.status.setLastError(errSkippedScrape)
-					continue
-				}
-				t.scrape(sampleAppender)
-			}
-		}
-	}
-}
-
-// StopScraper implements Target.
-func (t *Target) StopScraper() {
-	log.Debugf("Stopping scraper for target %v...", t)
-
-	close(t.scraperStopping)
-	<-t.scraperStopped
-
-	log.Debugf("Scraper for target %v stopped.", t)
-}
-
-const acceptHeader = `application/vnd.google.protobuf;proto=io.prometheus.client.MetricFamily;encoding=delimited;q=0.7,text/plain;version=0.0.4;q=0.3,application/json;schema="prometheus/telemetry";version=0.0.2;q=0.2,*/*;q=0.1`
-
-func (t *Target) scrape(appender storage.SampleAppender) error {
-	var (
-		err   error
-		start = time.Now()
-	)
-	defer func(appender storage.SampleAppender) {
-		t.report(appender, start, time.Since(start), err)
-	}(appender)
-
-	t.RLock()
-
-	appender = t.wrapAppender(appender)
-
-	client := t.httpClient
-	t.RUnlock()
-
-	req, err := http.NewRequest("GET", t.URL().String(), nil)
-	if err != nil {
-		return err
-	}
-	req.Header.Add("Accept", acceptHeader)
-
-	ctx, _ := context.WithTimeout(context.Background(), t.timeout())
-	resp, err := ctxhttp.Do(ctx, client, req)
-	if err != nil {
-		return err
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode != http.StatusOK {
-		return fmt.Errorf("server returned HTTP status %s", resp.Status)
-	}
-
-	dec := expfmt.NewDecoder(resp.Body, expfmt.ResponseFormat(resp.Header))
-
-	sdec := expfmt.SampleDecoder{
-		Dec: dec,
-		Opts: &expfmt.DecodeOptions{
-			Timestamp: model.TimeFromUnixNano(start.UnixNano()),
-		},
-	}
-
-	var (
-		samples       model.Vector
-		numOutOfOrder int
-		logger        = log.With("target", t.InstanceIdentifier())
-	)
-	for {
-		if err = sdec.Decode(&samples); err != nil {
-			break
-		}
-		for _, s := range samples {
-			err := appender.Append(s)
-			if err != nil {
-				if err == local.ErrOutOfOrderSample {
-					numOutOfOrder++
-				} else {
-					logger.With("sample", s).Warnf("Error inserting sample: %s", err)
-				}
-			}
-
-		}
-	}
-	if numOutOfOrder > 0 {
-		logger.With("numDropped", numOutOfOrder).Warn("Error on ingesting out-of-order samples")
-	}
-
-	if err == io.EOF {
-		// Set err to nil since it is used in the scrape health recording.
-		err = nil
-	}
-	return err
-}
-
-func (t *Target) report(app storage.SampleAppender, start time.Time, duration time.Duration, err error) {
-	t.status.setLastScrape(start)
-	t.status.setLastError(err)
-
-	ts := model.TimeFromUnixNano(start.UnixNano())
-
-	var health model.SampleValue
 	if err == nil {
-		health = 1
+		t.health = HealthGood
+	} else {
+		t.health = HealthBad
 	}
 
-	healthSample := &model.Sample{
-		Metric: model.Metric{
-			model.MetricNameLabel: scrapeHealthMetricName,
-		},
-		Timestamp: ts,
-		Value:     health,
-	}
-	durationSample := &model.Sample{
-		Metric: model.Metric{
-			model.MetricNameLabel: scrapeDurationMetricName,
-		},
-		Timestamp: ts,
-		Value:     model.SampleValue(float64(duration) / float64(time.Second)),
-	}
-
-	app = t.wrapReportingAppender(app)
-
-	app.Append(healthSample)
-	app.Append(durationSample)
+	t.lastError = err
+	t.lastScrape = start
 }
 
+// LastError returns the error encountered during the last scrape.
+func (t *Target) LastError() error {
+	t.mtx.RLock()
+	defer t.mtx.RUnlock()
+
+	return t.lastError
+}
+
+// LastScrape returns the time of the last scrape.
+func (t *Target) LastScrape() time.Time {
+	t.mtx.RLock()
+	defer t.mtx.RUnlock()
+
+	return t.lastScrape
+}
+
+// Health returns the last known health state of the target.
+func (t *Target) Health() TargetHealth {
+	t.mtx.RLock()
+	defer t.mtx.RUnlock()
+
+	return t.health
+}
+
+// Targets is a sortable list of targets.
+type Targets []*Target
+
+func (ts Targets) Len() int           { return len(ts) }
+func (ts Targets) Less(i, j int) bool { return ts[i].URL().String() < ts[j].URL().String() }
+func (ts Targets) Swap(i, j int)      { ts[i], ts[j] = ts[j], ts[i] }
+
 // Merges the ingested sample's metric with the label set. On a collision the
 // value of the ingested label is stored in a label prefixed with 'exported_'.
 type ruleLabelsAppender struct {
@@ -643,36 +284,3 @@ func (app relabelAppender) Append(s *model.Sample) error {
 
 	return app.SampleAppender.Append(s)
 }
-
-// Labels returns a copy of the set of all public labels of the target.
-func (t *Target) Labels() model.LabelSet {
-	t.RLock()
-	defer t.RUnlock()
-
-	return t.unlockedLabels()
-}
-
-// unlockedLabels does the same as Labels but does not lock the mutex (useful
-// for internal usage when the mutex is already locked).
-func (t *Target) unlockedLabels() model.LabelSet {
-	lset := make(model.LabelSet, len(t.labels))
-	for ln, lv := range t.labels {
-		if !strings.HasPrefix(string(ln), model.ReservedLabelPrefix) {
-			lset[ln] = lv
-		}
-	}
-
-	if _, ok := lset[model.InstanceLabel]; !ok {
-		lset[model.InstanceLabel] = t.labels[model.AddressLabel]
-	}
-
-	return lset
-}
-
-// MetaLabels returns a copy of the target's labels before any processing.
-func (t *Target) MetaLabels() model.LabelSet {
-	t.RLock()
-	defer t.RUnlock()
-
-	return t.metaLabels.Clone()
-}

retrieval/target_test.go

@@ -16,7 +16,6 @@ package retrieval
 import (
 	"crypto/tls"
 	"crypto/x509"
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -35,9 +34,8 @@ import (
 func TestTargetLabels(t *testing.T) {
 	target := newTestTarget("example.com:80", 0, model.LabelSet{"job": "some_job", "foo": "bar"})
 	want := model.LabelSet{
-		model.JobLabel:      "some_job",
-		model.InstanceLabel: "example.com:80",
-		"foo":               "bar",
+		model.JobLabel: "some_job",
+		"foo":          "bar",
 	}
 	got := target.Labels()
 	if !reflect.DeepEqual(want, got) {
@@ -91,484 +89,36 @@ func TestTargetOffset(t *testing.T) {
 	}
 }
 
-func TestTargetWrapReportingAppender(t *testing.T) {
-	cfg := &config.ScrapeConfig{
-		MetricRelabelConfigs: []*config.RelabelConfig{
-			{}, {}, {},
-		},
+func TestTargetURL(t *testing.T) {
+	params := url.Values{
+		"abc": []string{"foo", "bar", "baz"},
+		"xyz": []string{"hoo"},
+	}
+	labels := model.LabelSet{
+		model.AddressLabel:     "example.com:1234",
+		model.SchemeLabel:      "https",
+		model.MetricsPathLabel: "/metricz",
+		"__param_abc":          "overwrite",
+		"__param_cde":          "huu",
+	}
+	target := NewTarget(labels, labels, params)
+
+	// The reserved labels are concatenated into a full URL. The first value for each
+	// URL query parameter can be set/modified via labels as well.
+	expectedParams := url.Values{
+		"abc": []string{"overwrite", "bar", "baz"},
+		"cde": []string{"huu"},
+		"xyz": []string{"hoo"},
+	}
+	expectedURL := url.URL{
+		Scheme:   "https",
+		Host:     "example.com:1234",
+		Path:     "/metricz",
+		RawQuery: expectedParams.Encode(),
 	}
 
-	target := newTestTarget("example.com:80", 10*time.Millisecond, nil)
-	target.scrapeConfig = cfg
-	app := &nopAppender{}
-
-	cfg.HonorLabels = false
-	wrapped := target.wrapReportingAppender(app)
-
-	rl, ok := wrapped.(ruleLabelsAppender)
-	if !ok {
-		t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
-	}
-	if rl.SampleAppender != app {
-		t.Fatalf("Expected base appender but got %T", rl.SampleAppender)
-	}
-
-	cfg.HonorLabels = true
-	wrapped = target.wrapReportingAppender(app)
-
-	hl, ok := wrapped.(ruleLabelsAppender)
-	if !ok {
-		t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
-	}
-	if hl.SampleAppender != app {
-		t.Fatalf("Expected base appender but got %T", hl.SampleAppender)
-	}
-}
-
-func TestTargetWrapAppender(t *testing.T) {
-	cfg := &config.ScrapeConfig{
-		MetricRelabelConfigs: []*config.RelabelConfig{
-			{}, {}, {},
-		},
-	}
-
-	target := newTestTarget("example.com:80", 10*time.Millisecond, nil)
-	target.scrapeConfig = cfg
-	app := &nopAppender{}
-
-	cfg.HonorLabels = false
-	wrapped := target.wrapAppender(app)
-
-	rl, ok := wrapped.(ruleLabelsAppender)
-	if !ok {
-		t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
-	}
-	re, ok := rl.SampleAppender.(relabelAppender)
-	if !ok {
-		t.Fatalf("Expected relabelAppender but got %T", rl.SampleAppender)
-	}
-	if re.SampleAppender != app {
-		t.Fatalf("Expected base appender but got %T", re.SampleAppender)
-	}
-
-	cfg.HonorLabels = true
-	wrapped = target.wrapAppender(app)
-
-	hl, ok := wrapped.(honorLabelsAppender)
-	if !ok {
-		t.Fatalf("Expected honorLabelsAppender but got %T", wrapped)
-	}
-	re, ok = hl.SampleAppender.(relabelAppender)
-	if !ok {
-		t.Fatalf("Expected relabelAppender but got %T", hl.SampleAppender)
-	}
-	if re.SampleAppender != app {
-		t.Fatalf("Expected base appender but got %T", re.SampleAppender)
-	}
-}
-
-func TestOverwriteLabels(t *testing.T) {
-	type test struct {
-		metric       string
-		resultNormal model.Metric
-		resultHonor  model.Metric
-	}
-	var tests []test
-
-	server := httptest.NewServer(
-		http.HandlerFunc(
-			func(w http.ResponseWriter, r *http.Request) {
-				w.Header().Set("Content-Type", `text/plain; version=0.0.4`)
-				for _, test := range tests {
-					w.Write([]byte(test.metric))
-					w.Write([]byte(" 1\n"))
-				}
-			},
-		),
-	)
-	defer server.Close()
-	addr := model.LabelValue(strings.Split(server.URL, "://")[1])
-
-	tests = []test{
-		{
-			metric: `foo{}`,
-			resultNormal: model.Metric{
-				model.MetricNameLabel: "foo",
-				model.InstanceLabel:   addr,
-			},
-			resultHonor: model.Metric{
-				model.MetricNameLabel: "foo",
-				model.InstanceLabel:   addr,
-			},
-		},
-		{
-			metric: `foo{instance=""}`,
-			resultNormal: model.Metric{
-				model.MetricNameLabel: "foo",
-				model.InstanceLabel:   addr,
-			},
-			resultHonor: model.Metric{
-				model.MetricNameLabel: "foo",
-			},
-		},
-		{
-			metric: `foo{instance="other_instance"}`,
-			resultNormal: model.Metric{
-				model.MetricNameLabel:                           "foo",
-				model.InstanceLabel:                             addr,
-				model.ExportedLabelPrefix + model.InstanceLabel: "other_instance",
-			},
-			resultHonor: model.Metric{
-				model.MetricNameLabel: "foo",
-				model.InstanceLabel:   "other_instance",
-			},
-		},
-	}
-
-	target := newTestTarget(server.URL, time.Second, nil)
-
-	target.scrapeConfig.HonorLabels = false
-	app := &collectResultAppender{}
-	if err := target.scrape(app); err != nil {
-		t.Fatal(err)
-	}
-
-	for i, test := range tests {
-		if !reflect.DeepEqual(app.result[i].Metric, test.resultNormal) {
-			t.Errorf("Error comparing %q:\nExpected:\n%s\nGot:\n%s\n", test.metric, test.resultNormal, app.result[i].Metric)
-		}
-	}
-
-	target.scrapeConfig.HonorLabels = true
-	app = &collectResultAppender{}
-	if err := target.scrape(app); err != nil {
-		t.Fatal(err)
-	}
-
-	for i, test := range tests {
-		if !reflect.DeepEqual(app.result[i].Metric, test.resultHonor) {
-			t.Errorf("Error comparing %q:\nExpected:\n%s\nGot:\n%s\n", test.metric, test.resultHonor, app.result[i].Metric)
-		}
-
-	}
-}
-func TestTargetScrapeUpdatesState(t *testing.T) {
-	testTarget := newTestTarget("bad schema", 0, nil)
-
-	testTarget.scrape(nopAppender{})
-	if testTarget.status.Health() != HealthBad {
-		t.Errorf("Expected target state %v, actual: %v", HealthBad, testTarget.status.Health())
-	}
-}
-
-func TestTargetScrapeWithThrottledStorage(t *testing.T) {
-	server := httptest.NewServer(
-		http.HandlerFunc(
-			func(w http.ResponseWriter, r *http.Request) {
-				w.Header().Set("Content-Type", `text/plain; version=0.0.4`)
-				for i := 0; i < 10; i++ {
-					w.Write([]byte(
-						fmt.Sprintf("test_metric_%d{foo=\"bar\"} 123.456\n", i),
-					))
-				}
-			},
-		),
-	)
-	defer server.Close()
-
-	testTarget := newTestTarget(server.URL, time.Second, model.LabelSet{"dings": "bums"})
-
-	go testTarget.RunScraper(&collectResultAppender{throttled: true})
-
-	// Enough time for a scrape to happen.
-	time.Sleep(20 * time.Millisecond)
-
-	testTarget.StopScraper()
-	// Wait for it to take effect.
-	time.Sleep(20 * time.Millisecond)
-
-	if testTarget.status.Health() != HealthBad {
-		t.Errorf("Expected target state %v, actual: %v", HealthBad, testTarget.status.Health())
-	}
-	if testTarget.status.LastError() != errSkippedScrape {
-		t.Errorf("Expected target error %q, actual: %q", errSkippedScrape, testTarget.status.LastError())
-	}
-}
-
-func TestTargetScrapeMetricRelabelConfigs(t *testing.T) {
-	server := httptest.NewServer(
-		http.HandlerFunc(
-			func(w http.ResponseWriter, r *http.Request) {
-				w.Header().Set("Content-Type", `text/plain; version=0.0.4`)
-				w.Write([]byte("test_metric_drop 0\n"))
-				w.Write([]byte("test_metric_relabel 1\n"))
-			},
-		),
-	)
-	defer server.Close()
-	testTarget := newTestTarget(server.URL, time.Second, model.LabelSet{})
-	testTarget.scrapeConfig.MetricRelabelConfigs = []*config.RelabelConfig{
-		{
-			SourceLabels: model.LabelNames{"__name__"},
-			Regex:        config.MustNewRegexp(".*drop.*"),
-			Action:       config.RelabelDrop,
-		},
-		{
-			SourceLabels: model.LabelNames{"__name__"},
-			Regex:        config.MustNewRegexp(".*(relabel|up).*"),
-			TargetLabel:  "foo",
-			Replacement:  "bar",
-			Action:       config.RelabelReplace,
-		},
-	}
-
-	appender := &collectResultAppender{}
-	if err := testTarget.scrape(appender); err != nil {
-		t.Fatal(err)
-	}
-
-	// Remove variables part of result.
-	for _, sample := range appender.result {
-		sample.Timestamp = 0
-		sample.Value = 0
-	}
-
-	expected := []*model.Sample{
-		{
-			Metric: model.Metric{
-				model.MetricNameLabel: "test_metric_relabel",
-				"foo":               "bar",
-				model.InstanceLabel: model.LabelValue(testTarget.host()),
-			},
-			Timestamp: 0,
-			Value:     0,
-		},
-		// The metrics about the scrape are not affected.
-		{
-			Metric: model.Metric{
-				model.MetricNameLabel: scrapeHealthMetricName,
-				model.InstanceLabel:   model.LabelValue(testTarget.host()),
-			},
-			Timestamp: 0,
-			Value:     0,
-		},
-		{
-			Metric: model.Metric{
-				model.MetricNameLabel: scrapeDurationMetricName,
-				model.InstanceLabel:   model.LabelValue(testTarget.host()),
-			},
-			Timestamp: 0,
-			Value:     0,
-		},
-	}
-
-	if !appender.result.Equal(expected) {
-		t.Fatalf("Expected and actual samples not equal. Expected: %s, actual: %s", expected, appender.result)
-	}
-
-}
-
-func TestTargetRecordScrapeHealth(t *testing.T) {
-	var (
-		testTarget = newTestTarget("example.url:80", 0, model.LabelSet{model.JobLabel: "testjob"})
-		now        = model.Now()
-		appender   = &collectResultAppender{}
-	)
-
-	testTarget.report(appender, now.Time(), 2*time.Second, nil)
-
-	result := appender.result
-
-	if len(result) != 2 {
-		t.Fatalf("Expected two samples, got %d", len(result))
-	}
-
-	actual := result[0]
-	expected := &model.Sample{
-		Metric: model.Metric{
-			model.MetricNameLabel: scrapeHealthMetricName,
-			model.InstanceLabel:   "example.url:80",
-			model.JobLabel:        "testjob",
-		},
-		Timestamp: now,
-		Value:     1,
-	}
-
-	if !actual.Equal(expected) {
-		t.Fatalf("Expected and actual samples not equal. Expected: %v, actual: %v", expected, actual)
-	}
-
-	actual = result[1]
-	expected = &model.Sample{
-		Metric: model.Metric{
-			model.MetricNameLabel: scrapeDurationMetricName,
-			model.InstanceLabel:   "example.url:80",
-			model.JobLabel:        "testjob",
-		},
-		Timestamp: now,
-		Value:     2.0,
-	}
-
-	if !actual.Equal(expected) {
-		t.Fatalf("Expected and actual samples not equal. Expected: %v, actual: %v", expected, actual)
-	}
-}
-
-func TestTargetScrapeTimeout(t *testing.T) {
-	signal := make(chan bool, 1)
-	server := httptest.NewServer(
-		http.HandlerFunc(
-			func(w http.ResponseWriter, r *http.Request) {
-				<-signal
-				w.Header().Set("Content-Type", `text/plain; version=0.0.4`)
-				w.Write([]byte{})
-			},
-		),
-	)
-	defer server.Close()
-
-	testTarget := newTestTarget(server.URL, 50*time.Millisecond, model.LabelSet{})
-
-	appender := nopAppender{}
-
-	// scrape once without timeout
-	signal <- true
-	if err := testTarget.scrape(appender); err != nil {
-		t.Fatal(err)
-	}
-
-	// let the deadline lapse
-	time.Sleep(55 * time.Millisecond)
-
-	// now scrape again
-	signal <- true
-	if err := testTarget.scrape(appender); err != nil {
-		t.Fatal(err)
-	}
-
-	// now timeout
-	if err := testTarget.scrape(appender); err == nil {
-		t.Fatal("expected scrape to timeout")
-	} else {
-		signal <- true // let handler continue
-	}
-
-	// now scrape again without timeout
-	signal <- true
-	if err := testTarget.scrape(appender); err != nil {
-		t.Fatal(err)
-	}
-}
-
-func TestTargetScrape404(t *testing.T) {
-	server := httptest.NewServer(
-		http.HandlerFunc(
-			func(w http.ResponseWriter, r *http.Request) {
-				w.WriteHeader(http.StatusNotFound)
-			},
-		),
-	)
-	defer server.Close()
-
-	testTarget := newTestTarget(server.URL, time.Second, model.LabelSet{})
-	appender := nopAppender{}
-
-	want := errors.New("server returned HTTP status 404 Not Found")
-	got := testTarget.scrape(appender)
-	if got == nil || want.Error() != got.Error() {
-		t.Fatalf("want err %q, got %q", want, got)
-	}
-}
-
-func TestTargetRunScraperScrapes(t *testing.T) {
-	testTarget := newTestTarget("bad schema", 0, nil)
-
-	go testTarget.RunScraper(nopAppender{})
-
-	// Enough time for a scrape to happen.
-	time.Sleep(20 * time.Millisecond)
-	if testTarget.status.LastScrape().IsZero() {
-		t.Errorf("Scrape hasn't occured.")
-	}
-
-	testTarget.StopScraper()
-	// Wait for it to take effect.
-	time.Sleep(20 * time.Millisecond)
-	last := testTarget.status.LastScrape()
-	// Enough time for a scrape to happen.
-	time.Sleep(20 * time.Millisecond)
-	if testTarget.status.LastScrape() != last {
-		t.Errorf("Scrape occured after it was stopped.")
-	}
-}
-
-func BenchmarkScrape(b *testing.B) {
-	server := httptest.NewServer(
-		http.HandlerFunc(
-			func(w http.ResponseWriter, r *http.Request) {
-				w.Header().Set("Content-Type", `text/plain; version=0.0.4`)
-				w.Write([]byte("test_metric{foo=\"bar\"} 123.456\n"))
-			},
-		),
-	)
-	defer server.Close()
-
-	testTarget := newTestTarget(server.URL, time.Second, model.LabelSet{"dings": "bums"})
-	appender := nopAppender{}
-
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		if err := testTarget.scrape(appender); err != nil {
-			b.Fatal(err)
-		}
-	}
-}
-
-func TestURLParams(t *testing.T) {
-	server := httptest.NewServer(
-		http.HandlerFunc(
-			func(w http.ResponseWriter, r *http.Request) {
-				w.Header().Set("Content-Type", `text/plain; version=0.0.4`)
-				w.Write([]byte{})
-				r.ParseForm()
-				if r.Form["foo"][0] != "bar" {
-					t.Fatalf("URL parameter 'foo' had unexpected first value '%v'", r.Form["foo"][0])
-				}
-				if r.Form["foo"][1] != "baz" {
-					t.Fatalf("URL parameter 'foo' had unexpected second value '%v'", r.Form["foo"][1])
-				}
-			},
-		),
-	)
-	defer server.Close()
-	serverURL, err := url.Parse(server.URL)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	target, err := NewTarget(
-		&config.ScrapeConfig{
-			JobName:        "test_job1",
-			ScrapeInterval: model.Duration(1 * time.Minute),
-			ScrapeTimeout:  model.Duration(1 * time.Second),
-			Scheme:         serverURL.Scheme,
-			Params: url.Values{
-				"foo": []string{"bar", "baz"},
-			},
-		},
-		model.LabelSet{
-			model.SchemeLabel:  model.LabelValue(serverURL.Scheme),
-			model.AddressLabel: model.LabelValue(serverURL.Host),
-			"__param_foo":      "bar",
-		},
-		nil,
-	)
-	if err != nil {
-		t.Fatal(err)
-	}
-	app := &collectResultAppender{}
-	if err = target.scrape(app); err != nil {
-		t.Fatal(err)
+	if u := target.URL(); !reflect.DeepEqual(u.String(), expectedURL.String()) {
+		t.Fatalf("Expected URL %q but got %q", expectedURL, u)
 	}
 }
 
@@ -578,23 +128,9 @@ func newTestTarget(targetURL string, deadline time.Duration, labels model.LabelS
 	labels[model.AddressLabel] = model.LabelValue(strings.TrimLeft(targetURL, "http://"))
 	labels[model.MetricsPathLabel] = "/metrics"
 
-	t := &Target{
-		scrapeConfig: &config.ScrapeConfig{
-			ScrapeInterval: model.Duration(time.Millisecond),
-			ScrapeTimeout:  model.Duration(deadline),
-		},
-		labels:          labels,
-		status:          &TargetStatus{},
-		scraperStopping: make(chan struct{}),
-		scraperStopped:  make(chan struct{}),
+	return &Target{
+		labels: labels,
 	}
-
-	var err error
-	if t.httpClient, err = t.client(); err != nil {
-		panic(err)
-	}
-
-	return t
 }
 
 func TestNewHTTPBearerToken(t *testing.T) {
@@ -766,7 +302,7 @@ func newTLSConfig(t *testing.T) *tls.Config {
 	return tlsConfig
 }
 
-func TestNewTargetWithBadTLSConfig(t *testing.T) {
+func TestNewClientWithBadTLSConfig(t *testing.T) {
 	cfg := &config.ScrapeConfig{
 		ScrapeTimeout: model.Duration(1 * time.Second),
 		TLSConfig: config.TLSConfig{
@@ -775,7 +311,7 @@ func TestNewTargetWithBadTLSConfig(t *testing.T) {
 			KeyFile:  "testdata/nonexistent_client.key",
 		},
 	}
-	_, err := NewTarget(cfg, nil, nil)
+	_, err := newHTTPClient(cfg)
 	if err == nil {
 		t.Fatalf("Expected error, got nil.")
 	}

retrieval/targetmanager.go

@@ -17,9 +17,11 @@ import (
 	"fmt"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
+	"golang.org/x/net/context"
 
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/retrieval/discovery"
@@ -33,285 +35,102 @@ import (
 // The TargetProvider does not have to guarantee that an actual change happened.
 // It does guarantee that it sends the new TargetGroup whenever a change happens.
 //
-// Sources() is guaranteed to be called exactly once before each call to Run().
-// On a call to Run() implementing types must send a valid target group for each of
-// the sources they declared in the last call to Sources().
+// Providers must initially send all known target groups as soon as it can.
 type TargetProvider interface {
-	// Sources returns the source identifiers the provider is currently aware of.
-	Sources() []string
 	// Run hands a channel to the target provider through which it can send
 	// updated target groups. The channel must be closed by the target provider
 	// if no more updates will be sent.
 	// On receiving from done Run must return.
-	Run(up chan<- config.TargetGroup, done <-chan struct{})
+	Run(ctx context.Context, up chan<- []*config.TargetGroup)
 }
 
 // TargetManager maintains a set of targets, starts and stops their scraping and
 // creates the new targets based on the target groups it receives from various
 // target providers.
 type TargetManager struct {
-	mtx            sync.RWMutex
-	sampleAppender storage.SampleAppender
-	running        bool
-	done           chan struct{}
+	appender      storage.SampleAppender
+	scrapeConfigs []*config.ScrapeConfig
 
-	// Targets by their source ID.
-	targets map[string][]*Target
-	// Providers by the scrape configs they are derived from.
-	providers map[*config.ScrapeConfig][]TargetProvider
+	mtx    sync.RWMutex
+	ctx    context.Context
+	cancel func()
+	wg     sync.WaitGroup
+
+	// Set of unqiue targets by scrape configuration.
+	targetSets map[string]*targetSet
 }
 
 // NewTargetManager creates a new TargetManager.
-func NewTargetManager(sampleAppender storage.SampleAppender) *TargetManager {
-	tm := &TargetManager{
-		sampleAppender: sampleAppender,
-		targets:        map[string][]*Target{},
+func NewTargetManager(app storage.SampleAppender) *TargetManager {
+	return &TargetManager{
+		appender:   app,
+		targetSets: map[string]*targetSet{},
 	}
-	return tm
-}
-
-// merge multiple target group channels into a single output channel.
-func merge(done <-chan struct{}, cs ...<-chan targetGroupUpdate) <-chan targetGroupUpdate {
-	var wg sync.WaitGroup
-	out := make(chan targetGroupUpdate)
-
-	// Start an output goroutine for each input channel in cs.  output
-	// copies values from c to out until c or done is closed, then calls
-	// wg.Done.
-	redir := func(c <-chan targetGroupUpdate) {
-		defer wg.Done()
-		for n := range c {
-			select {
-			case out <- n:
-			case <-done:
-				return
-			}
-		}
-	}
-
-	wg.Add(len(cs))
-	for _, c := range cs {
-		go redir(c)
-	}
-
-	// Close the out channel if all inbound channels are closed.
-	go func() {
-		wg.Wait()
-		close(out)
-	}()
-	return out
-}
-
-// targetGroupUpdate is a potentially changed/new target group
-// for the given scrape configuration.
-type targetGroupUpdate struct {
-	tg   config.TargetGroup
-	scfg *config.ScrapeConfig
 }
 
 // Run starts background processing to handle target updates.
 func (tm *TargetManager) Run() {
 	log.Info("Starting target manager...")
 
-	tm.done = make(chan struct{})
-
-	sources := map[string]struct{}{}
-	updates := []<-chan targetGroupUpdate{}
-
-	for scfg, provs := range tm.providers {
-		for _, prov := range provs {
-			// Get an initial set of available sources so we don't remove
-			// target groups from the last run that are still available.
-			for _, src := range prov.Sources() {
-				sources[src] = struct{}{}
-			}
-
-			tgc := make(chan config.TargetGroup)
-			// Run the target provider after cleanup of the stale targets is done.
-			defer func(prov TargetProvider, tgc chan<- config.TargetGroup, done <-chan struct{}) {
-				go prov.Run(tgc, done)
-			}(prov, tgc, tm.done)
-
-			tgupc := make(chan targetGroupUpdate)
-			updates = append(updates, tgupc)
-
-			go func(scfg *config.ScrapeConfig, done <-chan struct{}) {
-				defer close(tgupc)
-				for {
-					select {
-					case tg := <-tgc:
-						tgupc <- targetGroupUpdate{tg: tg, scfg: scfg}
-					case <-done:
-						return
-					}
-				}
-			}(scfg, tm.done)
-		}
-	}
-
-	// Merge all channels of incoming target group updates into a single
-	// one and keep applying the updates.
-	go tm.handleUpdates(merge(tm.done, updates...), tm.done)
-
 	tm.mtx.Lock()
-	defer tm.mtx.Unlock()
 
-	// Remove old target groups that are no longer in the set of sources.
-	tm.removeTargets(func(src string) bool {
-		if _, ok := sources[src]; ok {
-			return false
-		}
-		return true
-	})
+	tm.ctx, tm.cancel = context.WithCancel(context.Background())
+	tm.reload()
 
-	tm.running = true
-	log.Info("Target manager started.")
-}
+	tm.mtx.Unlock()
 
-// handleUpdates receives target group updates and handles them in the
-// context of the given job config.
-func (tm *TargetManager) handleUpdates(ch <-chan targetGroupUpdate, done <-chan struct{}) {
-	for {
-		select {
-		case update, ok := <-ch:
-			if !ok {
-				return
-			}
-			log.Debugf("Received potential update for target group %q", update.tg.Source)
-
-			if err := tm.updateTargetGroup(&update.tg, update.scfg); err != nil {
-				log.Errorf("Error updating targets: %s", err)
-			}
-		case <-done:
-			return
-		}
-	}
+	tm.wg.Wait()
 }
 
 // Stop all background processing.
 func (tm *TargetManager) Stop() {
-	tm.mtx.RLock()
-	if tm.running {
-		defer tm.stop(true)
-	}
-	// Return the lock before calling tm.stop().
-	defer tm.mtx.RUnlock()
-}
-
-// stop background processing of the target manager. If removeTargets is true,
-// existing targets will be stopped and removed.
-func (tm *TargetManager) stop(removeTargets bool) {
-	log.Info("Stopping target manager...")
-	defer log.Info("Target manager stopped.")
-
-	close(tm.done)
+	log.Infoln("Stopping target manager...")
 
 	tm.mtx.Lock()
-	defer tm.mtx.Unlock()
+	// Cancel the base context, this will cause all target providers to shut down
+	// and all in-flight scrapes to abort immmediately.
+	// Started inserts will be finished before terminating.
+	tm.cancel()
+	tm.mtx.Unlock()
 
-	if removeTargets {
-		tm.removeTargets(nil)
-	}
+	// Wait for all scrape inserts to complete.
+	tm.wg.Wait()
 
-	tm.running = false
+	log.Debugln("Target manager stopped")
 }
 
-// removeTargets stops and removes targets for sources where f(source) is true
-// or if f is nil. This method is not thread-safe.
-func (tm *TargetManager) removeTargets(f func(string) bool) {
-	if f == nil {
-		f = func(string) bool { return true }
-	}
-	var wg sync.WaitGroup
-	for src, targets := range tm.targets {
-		if !f(src) {
-			continue
-		}
-		wg.Add(len(targets))
-		for _, target := range targets {
-			go func(t *Target) {
-				t.StopScraper()
-				wg.Done()
-			}(target)
-		}
-		delete(tm.targets, src)
-	}
-	wg.Wait()
-}
+func (tm *TargetManager) reload() {
+	jobs := map[string]struct{}{}
 
-// updateTargetGroup creates new targets for the group and replaces the old targets
-// for the source ID.
-func (tm *TargetManager) updateTargetGroup(tgroup *config.TargetGroup, cfg *config.ScrapeConfig) error {
-	newTargets, err := tm.targetsFromGroup(tgroup, cfg)
-	if err != nil {
-		return err
+	// Start new target sets and update existing ones.
+	for _, scfg := range tm.scrapeConfigs {
+		jobs[scfg.JobName] = struct{}{}
+
+		ts, ok := tm.targetSets[scfg.JobName]
+		if !ok {
+			ts = newTargetSet(scfg, tm.appender)
+			tm.targetSets[scfg.JobName] = ts
+
+			tm.wg.Add(1)
+
+			go func(ts *targetSet) {
+				ts.runScraping(tm.ctx)
+				tm.wg.Done()
+			}(ts)
+		} else {
+			ts.reload(scfg)
+		}
+		ts.runProviders(tm.ctx, providersFromConfig(scfg))
 	}
 
-	tm.mtx.Lock()
-	defer tm.mtx.Unlock()
-
-	if !tm.running {
-		return nil
-	}
-
-	oldTargets, ok := tm.targets[tgroup.Source]
-	if ok {
-		var wg sync.WaitGroup
-		// Replace the old targets with the new ones while keeping the state
-		// of intersecting targets.
-		for i, tnew := range newTargets {
-			var match *Target
-			for j, told := range oldTargets {
-				if told == nil {
-					continue
-				}
-				if tnew.fingerprint() == told.fingerprint() {
-					match = told
-					oldTargets[j] = nil
-					break
-				}
-			}
-			// Update the existing target and discard the new equivalent.
-			// Otherwise start scraping the new target.
-			if match != nil {
-				// Updating is blocked during a scrape. We don't want those wait times
-				// to build up.
-				wg.Add(1)
-				go func(t *Target) {
-					if err := match.Update(cfg, t.labels, t.metaLabels); err != nil {
-						log.Errorf("Error updating target %v: %v", t, err)
-					}
-					wg.Done()
-				}(tnew)
-				newTargets[i] = match
-			} else {
-				go tnew.RunScraper(tm.sampleAppender)
-			}
-		}
-		// Remove all old targets that disappeared.
-		for _, told := range oldTargets {
-			if told != nil {
-				wg.Add(1)
-				go func(t *Target) {
-					t.StopScraper()
-					wg.Done()
-				}(told)
-			}
-		}
-		wg.Wait()
-	} else {
-		// The source ID is new, start all target scrapers.
-		for _, tnew := range newTargets {
-			go tnew.RunScraper(tm.sampleAppender)
+	// Remove old target sets. Waiting for stopping is already guaranteed
+	// by the goroutine that started the target set.
+	for name, ts := range tm.targetSets {
+		if _, ok := jobs[name]; !ok {
+			ts.cancel()
+			delete(tm.targetSets, name)
 		}
 	}
-
-	if len(newTargets) > 0 {
-		tm.targets[tgroup.Source] = newTargets
-	} else {
-		delete(tm.targets, tgroup.Source)
-	}
-	return nil
 }
 
 // Pools returns the targets currently being scraped bucketed by their job name.
@@ -321,11 +140,16 @@ func (tm *TargetManager) Pools() map[string][]*Target {
 
 	pools := map[string][]*Target{}
 
-	for _, ts := range tm.targets {
-		for _, t := range ts {
+	// TODO(fabxc): this is just a hack to maintain compatibility for now.
+	for _, ps := range tm.targetSets {
+		ps.scrapePool.mtx.RLock()
+
+		for _, t := range ps.scrapePool.targets {
 			job := string(t.Labels()[model.JobLabel])
 			pools[job] = append(pools[job], t)
 		}
+
+		ps.scrapePool.mtx.RUnlock()
 	}
 	return pools
 }
@@ -334,79 +158,196 @@ func (tm *TargetManager) Pools() map[string][]*Target {
 // by the new cfg. The state of targets that are valid in the new configuration remains unchanged.
 // Returns true on success.
 func (tm *TargetManager) ApplyConfig(cfg *config.Config) bool {
-	tm.mtx.RLock()
-	running := tm.running
-	tm.mtx.RUnlock()
-
-	if running {
-		tm.stop(false)
-		// Even if updating the config failed, we want to continue rather than stop scraping anything.
-		defer tm.Run()
-	}
-	providers := map[*config.ScrapeConfig][]TargetProvider{}
-
-	for _, scfg := range cfg.ScrapeConfigs {
-		providers[scfg] = providersFromConfig(scfg)
-	}
-
 	tm.mtx.Lock()
 	defer tm.mtx.Unlock()
 
-	tm.providers = providers
+	tm.scrapeConfigs = cfg.ScrapeConfigs
+
+	if tm.ctx != nil {
+		tm.reload()
+	}
 	return true
 }
 
-// prefixedTargetProvider wraps TargetProvider and prefixes source strings
-// to make the sources unique across a configuration.
-type prefixedTargetProvider struct {
-	TargetProvider
+// targetSet holds several TargetProviders for which the same scrape configuration
+// is used. It maintains target groups from all given providers and sync them
+// to a scrape pool.
+type targetSet struct {
+	mtx sync.RWMutex
 
-	job       string
-	mechanism string
-	idx       int
+	// Sets of targets by a source string that is unique across target providers.
+	tgroups   map[string][]*Target
+	providers map[string]TargetProvider
+
+	scrapePool *scrapePool
+	config     *config.ScrapeConfig
+
+	syncCh          chan struct{}
+	cancelScraping  func()
+	cancelProviders func()
 }
 
-func (tp *prefixedTargetProvider) prefix(src string) string {
-	return fmt.Sprintf("%s:%s:%d:%s", tp.job, tp.mechanism, tp.idx, src)
-}
-
-func (tp *prefixedTargetProvider) Sources() []string {
-	srcs := tp.TargetProvider.Sources()
-	for i, src := range srcs {
-		srcs[i] = tp.prefix(src)
+func newTargetSet(cfg *config.ScrapeConfig, app storage.SampleAppender) *targetSet {
+	ts := &targetSet{
+		tgroups:    map[string][]*Target{},
+		scrapePool: newScrapePool(cfg, app),
+		syncCh:     make(chan struct{}, 1),
+		config:     cfg,
 	}
-
-	return srcs
+	return ts
 }
 
-func (tp *prefixedTargetProvider) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
-	defer close(ch)
+func (ts *targetSet) cancel() {
+	ts.mtx.RLock()
+	defer ts.mtx.RUnlock()
 
-	ch2 := make(chan config.TargetGroup)
-	go tp.TargetProvider.Run(ch2, done)
+	if ts.cancelScraping != nil {
+		ts.cancelScraping()
+	}
+	if ts.cancelProviders != nil {
+		ts.cancelProviders()
+	}
+}
 
+func (ts *targetSet) reload(cfg *config.ScrapeConfig) {
+	ts.mtx.Lock()
+	ts.config = cfg
+	ts.mtx.Unlock()
+
+	ts.scrapePool.reload(cfg)
+}
+
+func (ts *targetSet) runScraping(ctx context.Context) {
+	ctx, ts.cancelScraping = context.WithCancel(ctx)
+
+	ts.scrapePool.ctx = ctx
+
+Loop:
 	for {
+		// Throttle syncing to once per five seconds.
 		select {
-		case <-done:
-			return
-		case tg := <-ch2:
-			tg.Source = tp.prefix(tg.Source)
-			ch <- tg
+		case <-ctx.Done():
+			break Loop
+		case <-time.After(5 * time.Second):
+		}
+
+		select {
+		case <-ctx.Done():
+			break Loop
+		case <-ts.syncCh:
+			ts.mtx.RLock()
+			ts.sync()
+			ts.mtx.RUnlock()
 		}
 	}
+
+	// We want to wait for all pending target scrapes to complete though to ensure there'll
+	// be no more storage writes after this point.
+	ts.scrapePool.stop()
+}
+
+func (ts *targetSet) sync() {
+	var all []*Target
+	for _, targets := range ts.tgroups {
+		all = append(all, targets...)
+	}
+	ts.scrapePool.sync(all)
+}
+
+func (ts *targetSet) runProviders(ctx context.Context, providers map[string]TargetProvider) {
+	// Lock for the entire time. This may mean up to 5 seconds until the full initial set
+	// is retrieved and applied.
+	// We could release earlier with some tweaks, but this is easier to reason about.
+	ts.mtx.Lock()
+	defer ts.mtx.Unlock()
+
+	var wg sync.WaitGroup
+
+	if ts.cancelProviders != nil {
+		ts.cancelProviders()
+	}
+	ctx, ts.cancelProviders = context.WithCancel(ctx)
+
+	for name, prov := range providers {
+		wg.Add(1)
+
+		updates := make(chan []*config.TargetGroup)
+
+		go func(name string, prov TargetProvider) {
+			var initial []*config.TargetGroup
+
+			select {
+			case <-ctx.Done():
+				wg.Done()
+				return
+			case initial = <-updates:
+				// First set of all targets the provider knows.
+			case <-time.After(5 * time.Second):
+				// Initial set didn't arrive. Act as if it was empty
+				// and wait for updates later on.
+			}
+
+			for _, tgroup := range initial {
+				targets, err := targetsFromGroup(tgroup, ts.config)
+				if err != nil {
+					log.With("target_group", tgroup).Errorf("Target update failed: %s", err)
+					continue
+				}
+				ts.tgroups[name+"/"+tgroup.Source] = targets
+			}
+
+			wg.Done()
+
+			// Start listening for further updates.
+			for {
+				select {
+				case <-ctx.Done():
+					return
+				case tgs := <-updates:
+					for _, tg := range tgs {
+						if err := ts.update(name, tg); err != nil {
+							log.With("target_group", tg).Errorf("Target update failed: %s", err)
+						}
+					}
+				}
+			}
+		}(name, prov)
+
+		go prov.Run(ctx, updates)
+	}
+
+	// We wait for a full initial set of target groups before releasing the mutex
+	// to ensure the initial sync is complete and there are no races with subsequent updates.
+	wg.Wait()
+	ts.sync()
+}
+
+// update handles a target group update from a target provider identified by the name.
+func (ts *targetSet) update(name string, tgroup *config.TargetGroup) error {
+	targets, err := targetsFromGroup(tgroup, ts.config)
+	if err != nil {
+		return err
+	}
+
+	ts.mtx.Lock()
+	defer ts.mtx.Unlock()
+
+	ts.tgroups[name+"/"+tgroup.Source] = targets
+
+	select {
+	case ts.syncCh <- struct{}{}:
+	default:
+	}
+
+	return nil
 }
 
 // providersFromConfig returns all TargetProviders configured in cfg.
-func providersFromConfig(cfg *config.ScrapeConfig) []TargetProvider {
-	var providers []TargetProvider
+func providersFromConfig(cfg *config.ScrapeConfig) map[string]TargetProvider {
+	providers := map[string]TargetProvider{}
 
 	app := func(mech string, i int, tp TargetProvider) {
-		providers = append(providers, &prefixedTargetProvider{
-			job:            cfg.JobName,
-			mechanism:      mech,
-			idx:            i,
-			TargetProvider: tp,
-		})
+		providers[fmt.Sprintf("%s/%d", mech, i)] = tp
 	}
 
 	for i, c := range cfg.DNSSDConfigs {
@@ -451,11 +392,9 @@ func providersFromConfig(cfg *config.ScrapeConfig) []TargetProvider {
 }
 
 // targetsFromGroup builds targets based on the given TargetGroup and config.
-func (tm *TargetManager) targetsFromGroup(tg *config.TargetGroup, cfg *config.ScrapeConfig) ([]*Target, error) {
-	tm.mtx.RLock()
-	defer tm.mtx.RUnlock()
-
+func targetsFromGroup(tg *config.TargetGroup, cfg *config.ScrapeConfig) ([]*Target, error) {
 	targets := make([]*Target, 0, len(tg.Targets))
+
 	for i, labels := range tg.Targets {
 		for k, v := range cfg.Params {
 			if len(v) > 0 {
@@ -518,11 +457,12 @@ func (tm *TargetManager) targetsFromGroup(tg *config.TargetGroup, cfg *config.Sc
 				delete(labels, ln)
 			}
 		}
-		tr, err := NewTarget(cfg, labels, preRelabelLabels)
-		if err != nil {
-			return nil, fmt.Errorf("error while creating instance %d in target group %s: %s", i, tg, err)
+
+		if _, ok := labels[model.InstanceLabel]; !ok {
+			labels[model.InstanceLabel] = labels[model.AddressLabel]
 		}
-		targets = append(targets, tr)
+
+		targets = append(targets, NewTarget(labels, preRelabelLabels, cfg.Params))
 	}
 
 	return targets, nil
@@ -539,29 +479,16 @@ func NewStaticProvider(groups []*config.TargetGroup) *StaticProvider {
 	for i, tg := range groups {
 		tg.Source = fmt.Sprintf("%d", i)
 	}
-	return &StaticProvider{
-		TargetGroups: groups,
-	}
+	return &StaticProvider{groups}
 }
 
 // Run implements the TargetProvider interface.
-func (sd *StaticProvider) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
-	defer close(ch)
-
-	for _, tg := range sd.TargetGroups {
-		select {
-		case <-done:
-			return
-		case ch <- *tg:
-		}
+func (sd *StaticProvider) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
+	// We still have to consider that the consumer exits right away in which case
+	// the context will be canceled.
+	select {
+	case ch <- sd.TargetGroups:
+	case <-ctx.Done():
 	}
-	<-done
-}
-
-// Sources returns the provider's sources.
-func (sd *StaticProvider) Sources() (srcs []string) {
-	for _, tg := range sd.TargetGroups {
-		srcs = append(srcs, tg.Source)
-	}
-	return srcs
+	close(ch)
 }

retrieval/targetmanager_test.go

@@ -12,492 +12,3 @@
 // limitations under the License.
 
 package retrieval
-
-import (
-	"net/url"
-	"reflect"
-	"testing"
-	"time"
-
-	"github.com/prometheus/common/model"
-
-	"github.com/prometheus/prometheus/config"
-)
-
-func TestPrefixedTargetProvider(t *testing.T) {
-	targetGroups := []*config.TargetGroup{
-		{
-			Targets: []model.LabelSet{
-				{model.AddressLabel: "test-1:1234"},
-			},
-		}, {
-			Targets: []model.LabelSet{
-				{model.AddressLabel: "test-1:1235"},
-			},
-		},
-	}
-
-	tp := &prefixedTargetProvider{
-		job:            "job-x",
-		mechanism:      "static",
-		idx:            123,
-		TargetProvider: NewStaticProvider(targetGroups),
-	}
-
-	expSources := []string{
-		"job-x:static:123:0",
-		"job-x:static:123:1",
-	}
-	if !reflect.DeepEqual(tp.Sources(), expSources) {
-		t.Fatalf("expected sources %v, got %v", expSources, tp.Sources())
-	}
-
-	ch := make(chan config.TargetGroup)
-	done := make(chan struct{})
-
-	defer close(done)
-	go tp.Run(ch, done)
-
-	expGroup1 := *targetGroups[0]
-	expGroup2 := *targetGroups[1]
-	expGroup1.Source = "job-x:static:123:0"
-	expGroup2.Source = "job-x:static:123:1"
-
-	// The static target provider sends on the channel once per target group.
-	if tg := <-ch; !reflect.DeepEqual(tg, expGroup1) {
-		t.Fatalf("expected target group %v, got %v", expGroup1, tg)
-	}
-	if tg := <-ch; !reflect.DeepEqual(tg, expGroup2) {
-		t.Fatalf("expected target group %v, got %v", expGroup2, tg)
-	}
-}
-
-func TestTargetManagerChan(t *testing.T) {
-	testJob1 := &config.ScrapeConfig{
-		JobName:        "test_job1",
-		ScrapeInterval: model.Duration(1 * time.Minute),
-		TargetGroups: []*config.TargetGroup{{
-			Targets: []model.LabelSet{
-				{model.AddressLabel: "example.org:80"},
-				{model.AddressLabel: "example.com:80"},
-			},
-		}},
-	}
-	prov1 := &fakeTargetProvider{
-		sources: []string{"src1", "src2"},
-		update:  make(chan *config.TargetGroup),
-	}
-
-	targetManager := &TargetManager{
-		sampleAppender: nopAppender{},
-		providers: map[*config.ScrapeConfig][]TargetProvider{
-			testJob1: {prov1},
-		},
-		targets: make(map[string][]*Target),
-	}
-	go targetManager.Run()
-	defer targetManager.Stop()
-
-	sequence := []struct {
-		tgroup   *config.TargetGroup
-		expected map[string][]model.LabelSet
-	}{
-		{
-			tgroup: &config.TargetGroup{
-				Source: "src1",
-				Targets: []model.LabelSet{
-					{model.AddressLabel: "test-1:1234"},
-					{model.AddressLabel: "test-2:1234", "label": "set"},
-					{model.AddressLabel: "test-3:1234"},
-				},
-			},
-			expected: map[string][]model.LabelSet{
-				"src1": {
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-1:1234"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-2:1234", "label": "set"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-3:1234"},
-				},
-			},
-		}, {
-			tgroup: &config.TargetGroup{
-				Source: "src2",
-				Targets: []model.LabelSet{
-					{model.AddressLabel: "test-1:1235"},
-					{model.AddressLabel: "test-2:1235"},
-					{model.AddressLabel: "test-3:1235"},
-				},
-				Labels: model.LabelSet{"group": "label"},
-			},
-			expected: map[string][]model.LabelSet{
-				"src1": {
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-1:1234"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-2:1234", "label": "set"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-3:1234"},
-				},
-				"src2": {
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-1:1235", "group": "label"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-2:1235", "group": "label"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-3:1235", "group": "label"},
-				},
-			},
-		}, {
-			tgroup: &config.TargetGroup{
-				Source:  "src2",
-				Targets: []model.LabelSet{},
-			},
-			expected: map[string][]model.LabelSet{
-				"src1": {
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-1:1234"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-2:1234", "label": "set"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-3:1234"},
-				},
-			},
-		}, {
-			tgroup: &config.TargetGroup{
-				Source: "src1",
-				Targets: []model.LabelSet{
-					{model.AddressLabel: "test-1:1234", "added": "label"},
-					{model.AddressLabel: "test-3:1234"},
-					{model.AddressLabel: "test-4:1234", "fancy": "label"},
-				},
-			},
-			expected: map[string][]model.LabelSet{
-				"src1": {
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-1:1234", "added": "label"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-3:1234"},
-					{model.JobLabel: "test_job1", model.InstanceLabel: "test-4:1234", "fancy": "label"},
-				},
-			},
-		},
-	}
-
-	for i, step := range sequence {
-		prov1.update <- step.tgroup
-
-		time.Sleep(20 * time.Millisecond)
-
-		if len(targetManager.targets) != len(step.expected) {
-			t.Fatalf("step %d: sources mismatch %v, %v", i, targetManager.targets, step.expected)
-		}
-
-		for source, actTargets := range targetManager.targets {
-			expTargets, ok := step.expected[source]
-			if !ok {
-				t.Fatalf("step %d: unexpected source %q: %v", i, source, actTargets)
-			}
-			for _, expt := range expTargets {
-				found := false
-				for _, actt := range actTargets {
-					if reflect.DeepEqual(expt, actt.Labels()) {
-						found = true
-						break
-					}
-				}
-				if !found {
-					t.Errorf("step %d: expected target %v not found in actual targets", i, expt)
-				}
-			}
-		}
-	}
-}
-
-func TestTargetManagerConfigUpdate(t *testing.T) {
-	testJob1 := &config.ScrapeConfig{
-		JobName:        "test_job1",
-		ScrapeInterval: model.Duration(1 * time.Minute),
-		Params: url.Values{
-			"testParam": []string{"paramValue", "secondValue"},
-		},
-		TargetGroups: []*config.TargetGroup{{
-			Targets: []model.LabelSet{
-				{model.AddressLabel: "example.org:80"},
-				{model.AddressLabel: "example.com"},
-			},
-		}},
-		RelabelConfigs: []*config.RelabelConfig{
-			{
-				// Copy out the URL parameter.
-				SourceLabels: model.LabelNames{"__param_testParam"},
-				Regex:        config.MustNewRegexp("(.*)"),
-				TargetLabel:  "testParam",
-				Replacement:  "$1",
-				Action:       config.RelabelReplace,
-			},
-			{
-				// The port number is added after relabeling, so
-				// this relabel rule should have no effect.
-				SourceLabels: model.LabelNames{model.AddressLabel},
-				Regex:        config.MustNewRegexp("example.com:80"),
-				Action:       config.RelabelDrop,
-			},
-		},
-	}
-	testJob2 := &config.ScrapeConfig{
-		JobName:        "test_job2",
-		ScrapeInterval: model.Duration(1 * time.Minute),
-		TargetGroups: []*config.TargetGroup{
-			{
-				Targets: []model.LabelSet{
-					{model.AddressLabel: "example.org:8080"},
-					{model.AddressLabel: "example.com:8081"},
-				},
-				Labels: model.LabelSet{
-					"foo":  "bar",
-					"boom": "box",
-				},
-			},
-			{
-				Targets: []model.LabelSet{
-					{model.AddressLabel: "test.com:1234"},
-				},
-			},
-			{
-				Targets: []model.LabelSet{
-					{model.AddressLabel: "test.com:1235"},
-				},
-				Labels: model.LabelSet{"instance": "fixed"},
-			},
-		},
-		RelabelConfigs: []*config.RelabelConfig{
-			{
-				SourceLabels: model.LabelNames{model.AddressLabel},
-				Regex:        config.MustNewRegexp(`test\.(.*?):(.*)`),
-				Replacement:  "foo.${1}:${2}",
-				TargetLabel:  model.AddressLabel,
-				Action:       config.RelabelReplace,
-			},
-			{
-				// Add a new label for example.* targets.
-				SourceLabels: model.LabelNames{model.AddressLabel, "boom", "foo"},
-				Regex:        config.MustNewRegexp("example.*?-b([a-z-]+)r"),
-				TargetLabel:  "new",
-				Replacement:  "$1",
-				Separator:    "-",
-				Action:       config.RelabelReplace,
-			},
-			{
-				// Drop an existing label.
-				SourceLabels: model.LabelNames{"boom"},
-				Regex:        config.MustNewRegexp(".*"),
-				TargetLabel:  "boom",
-				Replacement:  "",
-				Action:       config.RelabelReplace,
-			},
-		},
-	}
-	// Test that targets without host:port addresses are dropped.
-	testJob3 := &config.ScrapeConfig{
-		JobName:        "test_job1",
-		ScrapeInterval: model.Duration(1 * time.Minute),
-		TargetGroups: []*config.TargetGroup{{
-			Targets: []model.LabelSet{
-				{model.AddressLabel: "example.net:80"},
-			},
-		}},
-		RelabelConfigs: []*config.RelabelConfig{
-			{
-				SourceLabels: model.LabelNames{model.AddressLabel},
-				Regex:        config.MustNewRegexp("(.*)"),
-				TargetLabel:  "__address__",
-				Replacement:  "http://$1",
-				Action:       config.RelabelReplace,
-			},
-		},
-	}
-
-	sequence := []struct {
-		scrapeConfigs []*config.ScrapeConfig
-		expected      map[string][]model.LabelSet
-	}{
-		{
-			scrapeConfigs: []*config.ScrapeConfig{testJob1},
-			expected: map[string][]model.LabelSet{
-				"test_job1:static:0:0": {
-					{
-						model.JobLabel:                       "test_job1",
-						"testParam":                          "paramValue",
-						model.SchemeLabel:                    "",
-						model.MetricsPathLabel:               "",
-						model.AddressLabel:                   "example.org:80",
-						model.ParamLabelPrefix + "testParam": "paramValue",
-					},
-					{
-						model.JobLabel:                       "test_job1",
-						"testParam":                          "paramValue",
-						model.SchemeLabel:                    "",
-						model.MetricsPathLabel:               "",
-						model.AddressLabel:                   "example.com:80",
-						model.ParamLabelPrefix + "testParam": "paramValue"},
-				},
-			},
-		}, {
-			scrapeConfigs: []*config.ScrapeConfig{testJob1},
-			expected: map[string][]model.LabelSet{
-				"test_job1:static:0:0": {
-					{
-						model.JobLabel:                       "test_job1",
-						"testParam":                          "paramValue",
-						model.SchemeLabel:                    "",
-						model.MetricsPathLabel:               "",
-						model.AddressLabel:                   "example.org:80",
-						model.ParamLabelPrefix + "testParam": "paramValue",
-					},
-					{
-						model.JobLabel:                       "test_job1",
-						"testParam":                          "paramValue",
-						model.SchemeLabel:                    "",
-						model.MetricsPathLabel:               "",
-						model.AddressLabel:                   "example.com:80",
-						model.ParamLabelPrefix + "testParam": "paramValue",
-					},
-				},
-			},
-		}, {
-			scrapeConfigs: []*config.ScrapeConfig{testJob1, testJob2},
-			expected: map[string][]model.LabelSet{
-				"test_job1:static:0:0": {
-					{
-						model.JobLabel:                       "test_job1",
-						"testParam":                          "paramValue",
-						model.SchemeLabel:                    "",
-						model.MetricsPathLabel:               "",
-						model.AddressLabel:                   "example.org:80",
-						model.ParamLabelPrefix + "testParam": "paramValue",
-					},
-					{
-						model.JobLabel:                       "test_job1",
-						"testParam":                          "paramValue",
-						model.SchemeLabel:                    "",
-						model.MetricsPathLabel:               "",
-						model.AddressLabel:                   "example.com:80",
-						model.ParamLabelPrefix + "testParam": "paramValue",
-					},
-				},
-				"test_job2:static:0:0": {
-					{
-						model.JobLabel:         "test_job2",
-						"foo":                  "bar",
-						"new":                  "ox-ba",
-						model.SchemeLabel:      "",
-						model.MetricsPathLabel: "",
-						model.AddressLabel:     "example.org:8080",
-					},
-					{
-						model.JobLabel:         "test_job2",
-						"foo":                  "bar",
-						"new":                  "ox-ba",
-						model.SchemeLabel:      "",
-						model.MetricsPathLabel: "",
-						model.AddressLabel:     "example.com:8081",
-					},
-				},
-				"test_job2:static:0:1": {
-					{
-						model.JobLabel:         "test_job2",
-						model.SchemeLabel:      "",
-						model.MetricsPathLabel: "",
-						model.AddressLabel:     "foo.com:1234",
-					},
-				},
-				"test_job2:static:0:2": {
-					{
-						model.JobLabel:         "test_job2",
-						model.InstanceLabel:    "fixed",
-						model.SchemeLabel:      "",
-						model.MetricsPathLabel: "",
-						model.AddressLabel:     "foo.com:1235",
-					},
-				},
-			},
-		}, {
-			scrapeConfigs: []*config.ScrapeConfig{},
-			expected:      map[string][]model.LabelSet{},
-		}, {
-			scrapeConfigs: []*config.ScrapeConfig{testJob2},
-			expected: map[string][]model.LabelSet{
-				"test_job2:static:0:0": {
-					{
-						model.JobLabel:         "test_job2",
-						"foo":                  "bar",
-						"new":                  "ox-ba",
-						model.SchemeLabel:      "",
-						model.MetricsPathLabel: "",
-						model.AddressLabel:     "example.org:8080"},
-					{
-						model.JobLabel:         "test_job2",
-						"foo":                  "bar",
-						"new":                  "ox-ba",
-						model.SchemeLabel:      "",
-						model.MetricsPathLabel: "",
-						model.AddressLabel:     "example.com:8081",
-					},
-				},
-				"test_job2:static:0:1": {
-					{
-						model.JobLabel:         "test_job2",
-						model.SchemeLabel:      "",
-						model.MetricsPathLabel: "",
-						model.AddressLabel:     "foo.com:1234",
-					},
-				},
-				"test_job2:static:0:2": {
-					{
-						model.JobLabel:         "test_job2",
-						model.InstanceLabel:    "fixed",
-						model.SchemeLabel:      "",
-						model.MetricsPathLabel: "",
-						model.AddressLabel:     "foo.com:1235",
-					},
-				},
-			},
-		}, {
-			scrapeConfigs: []*config.ScrapeConfig{testJob3},
-			expected:      map[string][]model.LabelSet{},
-		},
-	}
-	conf := &config.Config{}
-	*conf = config.DefaultConfig
-
-	targetManager := NewTargetManager(nopAppender{})
-	targetManager.ApplyConfig(conf)
-
-	targetManager.Run()
-	defer targetManager.Stop()
-
-	for i, step := range sequence {
-		conf.ScrapeConfigs = step.scrapeConfigs
-		targetManager.ApplyConfig(conf)
-
-		time.Sleep(50 * time.Millisecond)
-
-		if len(targetManager.targets) != len(step.expected) {
-			t.Fatalf("step %d: sources mismatch: expected %v, got %v", i, step.expected, targetManager.targets)
-		}
-
-		for source, actTargets := range targetManager.targets {
-			expTargets, ok := step.expected[source]
-			if !ok {
-				t.Fatalf("step %d: unexpected source %q: %v", i, source, actTargets)
-			}
-			for _, expt := range expTargets {
-				found := false
-				for _, actt := range actTargets {
-					if reflect.DeepEqual(expt, actt.labels) {
-						found = true
-						break
-					}
-				}
-				if !found {
-					t.Errorf("step %d: expected target %v for %q not found in actual targets", i, expt, source)
-				}
-			}
-		}
-	}
-}
-
-func TestHandleUpdatesReturnsWhenUpdateChanIsClosed(t *testing.T) {
-	tm := NewTargetManager(nopAppender{})
-	ch := make(chan targetGroupUpdate)
-	close(ch)
-	tm.handleUpdates(ch, make(chan struct{}))
-}

rules/alerting.go

@@ -110,6 +110,10 @@ func (rule *AlertingRule) Name() string {
 	return rule.name
 }
 
+func (r *AlertingRule) equal(o *AlertingRule) bool {
+	return r.name == o.name && r.labels.Equal(o.labels)
+}
+
 func (r *AlertingRule) sample(alert *Alert, ts model.Time, set bool) *model.Sample {
 	metric := model.Metric(r.labels.Clone())
 

rules/manager.go

@@ -28,7 +28,7 @@ import (
 	"github.com/prometheus/common/model"
 
 	"github.com/prometheus/prometheus/config"
-	"github.com/prometheus/prometheus/notification"
+	"github.com/prometheus/prometheus/notifier"
 	"github.com/prometheus/prometheus/promql"
 	"github.com/prometheus/prometheus/storage"
 	"github.com/prometheus/prometheus/template"
@@ -212,8 +212,12 @@ func (g *Group) copyState(from *Group) {
 			if !ok {
 				continue
 			}
-			if far.Name() == ar.Name() {
-				ar.active = far.active
+			// TODO(fabxc): forbid same alert definitions that are not unique by
+			// at least on static label or alertname?
+			if far.equal(ar) {
+				for fp, a := range far.active {
+					ar.active[fp] = a
+				}
 			}
 		}
 	}
@@ -343,7 +347,7 @@ func (g *Group) sendAlerts(rule *AlertingRule, timestamp model.Time) error {
 	}
 
 	if len(alerts) > 0 {
-		g.opts.NotificationHandler.Send(alerts...)
+		g.opts.Notifier.Send(alerts...)
 	}
 
 	return nil
@@ -359,10 +363,10 @@ type Manager struct {
 
 // ManagerOptions bundles options for the Manager.
 type ManagerOptions struct {
-	ExternalURL         *url.URL
-	QueryEngine         *promql.Engine
-	NotificationHandler *notification.Handler
-	SampleAppender      storage.SampleAppender
+	ExternalURL    *url.URL
+	QueryEngine    *promql.Engine
+	Notifier       *notifier.Notifier
+	SampleAppender storage.SampleAppender
 }
 
 // NewManager returns an implementation of Manager, ready to be started

scripts/build.sh

@@ -20,7 +20,7 @@ repo_path="github.com/prometheus/prometheus"
 version=$( cat version/VERSION )
 revision=$( git rev-parse --short HEAD 2> /dev/null || echo 'unknown' )
 branch=$( git rev-parse --abbrev-ref HEAD 2> /dev/null || echo 'unknown' )
-host=$( hostname -f )
+host=$( hostname )
 build_date=$( date +%Y%m%d-%H:%M:%S )
 go_version=$( go version | sed -e 's/^[^0-9.]*\([0-9.]*\).*/\1/' )
 

storage/local/heads.go

@@ -0,0 +1,242 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package local
+
+import (
+	"bufio"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"github.com/prometheus/common/model"
+
+	"github.com/prometheus/prometheus/storage/local/codable"
+)
+
+const (
+	headsFileName            = "heads.db"
+	headsTempFileName        = "heads.db.tmp"
+	headsFormatVersion       = 2
+	headsFormatLegacyVersion = 1 // Can read, but will never write.
+	headsMagicString         = "PrometheusHeads"
+)
+
+// headsScanner is a scanner to read time series with their heads from a
+// heads.db file. It follows a similar semantics as the bufio.Scanner.
+// It is not safe to use a headsScanner concurrently.
+type headsScanner struct {
+	f                    *os.File
+	r                    *bufio.Reader
+	fp                   model.Fingerprint // Read after each scan() call that has returned true.
+	series               *memorySeries     // Read after each scan() call that has returned true.
+	version              int64             // Read after newHeadsScanner has returned.
+	seriesTotal          uint64            // Read after newHeadsScanner has returned.
+	seriesCurrent        uint64
+	chunksToPersistTotal int64 // Read after scan() has returned false.
+	err                  error // Read after scan() has returned false.
+}
+
+func newHeadsScanner(filename string) *headsScanner {
+	hs := &headsScanner{}
+	defer func() {
+		if hs.f != nil && hs.err != nil {
+			hs.f.Close()
+		}
+	}()
+
+	if hs.f, hs.err = os.Open(filename); hs.err != nil {
+		return hs
+	}
+	hs.r = bufio.NewReaderSize(hs.f, fileBufSize)
+
+	buf := make([]byte, len(headsMagicString))
+	if _, hs.err = io.ReadFull(hs.r, buf); hs.err != nil {
+		return hs
+	}
+	magic := string(buf)
+	if magic != headsMagicString {
+		hs.err = fmt.Errorf(
+			"unexpected magic string, want %q, got %q",
+			headsMagicString, magic,
+		)
+		return hs
+	}
+	hs.version, hs.err = binary.ReadVarint(hs.r)
+	if (hs.version != headsFormatVersion && hs.version != headsFormatLegacyVersion) || hs.err != nil {
+		hs.err = fmt.Errorf(
+			"unknown or unreadable heads format version, want %d, got %d, error: %s",
+			headsFormatVersion, hs.version, hs.err,
+		)
+		return hs
+	}
+	if hs.seriesTotal, hs.err = codable.DecodeUint64(hs.r); hs.err != nil {
+		return hs
+	}
+	return hs
+}
+
+// scan works like bufio.Scanner.Scan.
+func (hs *headsScanner) scan() bool {
+	if hs.seriesCurrent == hs.seriesTotal || hs.err != nil {
+		return false
+	}
+
+	var (
+		seriesFlags      byte
+		fpAsInt          uint64
+		metric           codable.Metric
+		persistWatermark int64
+		modTimeNano      int64
+		modTime          time.Time
+		chunkDescsOffset int64
+		savedFirstTime   int64
+		numChunkDescs    int64
+		firstTime        int64
+		lastTime         int64
+		encoding         byte
+	)
+	if seriesFlags, hs.err = hs.r.ReadByte(); hs.err != nil {
+		return false
+	}
+	headChunkPersisted := seriesFlags&flagHeadChunkPersisted != 0
+	if fpAsInt, hs.err = codable.DecodeUint64(hs.r); hs.err != nil {
+		return false
+	}
+	hs.fp = model.Fingerprint(fpAsInt)
+
+	if hs.err = metric.UnmarshalFromReader(hs.r); hs.err != nil {
+		return false
+	}
+	if hs.version != headsFormatLegacyVersion {
+		// persistWatermark only present in v2.
+		persistWatermark, hs.err = binary.ReadVarint(hs.r)
+		if hs.err != nil {
+			return false
+		}
+		modTimeNano, hs.err = binary.ReadVarint(hs.r)
+		if hs.err != nil {
+			return false
+		}
+		if modTimeNano != -1 {
+			modTime = time.Unix(0, modTimeNano)
+		}
+	}
+	if chunkDescsOffset, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
+		return false
+	}
+	if savedFirstTime, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
+		return false
+	}
+
+	if numChunkDescs, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
+		return false
+	}
+	chunkDescs := make([]*chunkDesc, numChunkDescs)
+	if hs.version == headsFormatLegacyVersion {
+		if headChunkPersisted {
+			persistWatermark = numChunkDescs
+		} else {
+			persistWatermark = numChunkDescs - 1
+		}
+	}
+	headChunkClosed := true // Initial assumption.
+	for i := int64(0); i < numChunkDescs; i++ {
+		if i < persistWatermark {
+			if firstTime, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
+				return false
+			}
+			if lastTime, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
+				return false
+			}
+			chunkDescs[i] = &chunkDesc{
+				chunkFirstTime: model.Time(firstTime),
+				chunkLastTime:  model.Time(lastTime),
+			}
+			numMemChunkDescs.Inc()
+		} else {
+			// Non-persisted chunk.
+			// If there are non-persisted chunks at all, we consider
+			// the head chunk not to be closed yet.
+			headChunkClosed = false
+			if encoding, hs.err = hs.r.ReadByte(); hs.err != nil {
+				return false
+			}
+			chunk := newChunkForEncoding(chunkEncoding(encoding))
+			if hs.err = chunk.unmarshal(hs.r); hs.err != nil {
+				return false
+			}
+			cd := newChunkDesc(chunk, chunk.firstTime())
+			if i < numChunkDescs-1 {
+				// This is NOT the head chunk. So it's a chunk
+				// to be persisted, and we need to populate lastTime.
+				hs.chunksToPersistTotal++
+				cd.maybePopulateLastTime()
+			}
+			chunkDescs[i] = cd
+		}
+	}
+
+	hs.series = &memorySeries{
+		metric:           model.Metric(metric),
+		chunkDescs:       chunkDescs,
+		persistWatermark: int(persistWatermark),
+		modTime:          modTime,
+		chunkDescsOffset: int(chunkDescsOffset),
+		savedFirstTime:   model.Time(savedFirstTime),
+		lastTime:         chunkDescs[len(chunkDescs)-1].lastTime(),
+		headChunkClosed:  headChunkClosed,
+	}
+	hs.seriesCurrent++
+	return true
+}
+
+// close closes the underlying file if required.
+func (hs *headsScanner) close() {
+	if hs.f != nil {
+		hs.f.Close()
+	}
+}
+
+// DumpHeads writes the metadata of the provided heads file in a human-readable
+// form.
+func DumpHeads(filename string, out io.Writer) error {
+	hs := newHeadsScanner(filename)
+	defer hs.close()
+
+	if hs.err == nil {
+		fmt.Fprintf(
+			out,
+			">>> Dumping %d series from heads file %q with format version %d. <<<\n",
+			hs.seriesTotal, filename, hs.version,
+		)
+	}
+	for hs.scan() {
+		s := hs.series
+		fmt.Fprintf(
+			out,
+			"FP=%v\tMETRIC=%s\tlen(chunkDescs)=%d\tpersistWatermark=%d\tchunkDescOffset=%d\tsavedFirstTime=%v\tlastTime=%v\theadChunkClosed=%t\n",
+			hs.fp, s.metric, len(s.chunkDescs), s.persistWatermark, s.chunkDescsOffset, s.savedFirstTime, s.lastTime, s.headChunkClosed,
+		)
+	}
+	if hs.err == nil {
+		fmt.Fprintf(
+			out,
+			">>> Dump complete. %d chunks to persist. <<<\n",
+			hs.chunksToPersistTotal,
+		)
+	}
+	return hs.err
+}

storage/local/persistence.go

@@ -47,12 +47,6 @@ const (
 	seriesTempFileSuffix = ".db.tmp"
 	seriesDirNameLen     = 2 // How many bytes of the fingerprint in dir name.
 
-	headsFileName            = "heads.db"
-	headsTempFileName        = "heads.db.tmp"
-	headsFormatVersion       = 2
-	headsFormatLegacyVersion = 1 // Can read, but will never write.
-	headsMagicString         = "PrometheusHeads"
-
 	mappingsFileName      = "mappings.db"
 	mappingsTempFileName  = "mappings.db.tmp"
 	mappingsFormatVersion = 1
@@ -699,190 +693,36 @@ func (p *persistence) checkpointSeriesMapAndHeads(fingerprintToSeries *seriesMap
 // start-up while nothing else is running in storage land. This method is
 // utterly goroutine-unsafe.
 func (p *persistence) loadSeriesMapAndHeads() (sm *seriesMap, chunksToPersist int64, err error) {
-	var chunkDescsTotal int64
 	fingerprintToSeries := make(map[model.Fingerprint]*memorySeries)
 	sm = &seriesMap{m: fingerprintToSeries}
 
 	defer func() {
-		if sm != nil && p.dirty {
+		if p.dirty {
 			log.Warn("Persistence layer appears dirty.")
 			err = p.recoverFromCrash(fingerprintToSeries)
 			if err != nil {
 				sm = nil
 			}
 		}
-		if err == nil {
-			numMemChunkDescs.Add(float64(chunkDescsTotal))
-		}
 	}()
 
-	f, err := os.Open(p.headsFileName())
-	if os.IsNotExist(err) {
+	hs := newHeadsScanner(p.headsFileName())
+	defer hs.close()
+	for hs.scan() {
+		fingerprintToSeries[hs.fp] = hs.series
+	}
+	if os.IsNotExist(hs.err) {
 		return sm, 0, nil
 	}
-	if err != nil {
-		log.Warn("Could not open heads file:", err)
+	if hs.err != nil {
 		p.dirty = true
-		return
+		log.
+			With("file", p.headsFileName()).
+			With("error", hs.err).
+			Error("Error reading heads file.")
+		return sm, 0, hs.err
 	}
-	defer f.Close()
-	r := bufio.NewReaderSize(f, fileBufSize)
-
-	buf := make([]byte, len(headsMagicString))
-	if _, err := io.ReadFull(r, buf); err != nil {
-		log.Warn("Could not read from heads file:", err)
-		p.dirty = true
-		return sm, 0, nil
-	}
-	magic := string(buf)
-	if magic != headsMagicString {
-		log.Warnf(
-			"unexpected magic string, want %q, got %q",
-			headsMagicString, magic,
-		)
-		p.dirty = true
-		return
-	}
-	version, err := binary.ReadVarint(r)
-	if (version != headsFormatVersion && version != headsFormatLegacyVersion) || err != nil {
-		log.Warnf("unknown heads format version, want %d", headsFormatVersion)
-		p.dirty = true
-		return sm, 0, nil
-	}
-	numSeries, err := codable.DecodeUint64(r)
-	if err != nil {
-		log.Warn("Could not decode number of series:", err)
-		p.dirty = true
-		return sm, 0, nil
-	}
-
-	for ; numSeries > 0; numSeries-- {
-		seriesFlags, err := r.ReadByte()
-		if err != nil {
-			log.Warn("Could not read series flags:", err)
-			p.dirty = true
-			return sm, chunksToPersist, nil
-		}
-		headChunkPersisted := seriesFlags&flagHeadChunkPersisted != 0
-		fp, err := codable.DecodeUint64(r)
-		if err != nil {
-			log.Warn("Could not decode fingerprint:", err)
-			p.dirty = true
-			return sm, chunksToPersist, nil
-		}
-		var metric codable.Metric
-		if err := metric.UnmarshalFromReader(r); err != nil {
-			log.Warn("Could not decode metric:", err)
-			p.dirty = true
-			return sm, chunksToPersist, nil
-		}
-		var persistWatermark int64
-		var modTime time.Time
-		if version != headsFormatLegacyVersion {
-			// persistWatermark only present in v2.
-			persistWatermark, err = binary.ReadVarint(r)
-			if err != nil {
-				log.Warn("Could not decode persist watermark:", err)
-				p.dirty = true
-				return sm, chunksToPersist, nil
-			}
-			modTimeNano, err := binary.ReadVarint(r)
-			if err != nil {
-				log.Warn("Could not decode modification time:", err)
-				p.dirty = true
-				return sm, chunksToPersist, nil
-			}
-			if modTimeNano != -1 {
-				modTime = time.Unix(0, modTimeNano)
-			}
-		}
-		chunkDescsOffset, err := binary.ReadVarint(r)
-		if err != nil {
-			log.Warn("Could not decode chunk descriptor offset:", err)
-			p.dirty = true
-			return sm, chunksToPersist, nil
-		}
-		savedFirstTime, err := binary.ReadVarint(r)
-		if err != nil {
-			log.Warn("Could not decode saved first time:", err)
-			p.dirty = true
-			return sm, chunksToPersist, nil
-		}
-		numChunkDescs, err := binary.ReadVarint(r)
-		if err != nil {
-			log.Warn("Could not decode number of chunk descriptors:", err)
-			p.dirty = true
-			return sm, chunksToPersist, nil
-		}
-		chunkDescs := make([]*chunkDesc, numChunkDescs)
-		if version == headsFormatLegacyVersion {
-			if headChunkPersisted {
-				persistWatermark = numChunkDescs
-			} else {
-				persistWatermark = numChunkDescs - 1
-			}
-		}
-
-		headChunkClosed := true // Initial assumption.
-		for i := int64(0); i < numChunkDescs; i++ {
-			if i < persistWatermark {
-				firstTime, err := binary.ReadVarint(r)
-				if err != nil {
-					log.Warn("Could not decode first time:", err)
-					p.dirty = true
-					return sm, chunksToPersist, nil
-				}
-				lastTime, err := binary.ReadVarint(r)
-				if err != nil {
-					log.Warn("Could not decode last time:", err)
-					p.dirty = true
-					return sm, chunksToPersist, nil
-				}
-				chunkDescs[i] = &chunkDesc{
-					chunkFirstTime: model.Time(firstTime),
-					chunkLastTime:  model.Time(lastTime),
-				}
-				chunkDescsTotal++
-			} else {
-				// Non-persisted chunk.
-				// If there are non-persisted chunks at all, we consider
-				// the head chunk not to be closed yet.
-				headChunkClosed = false
-				encoding, err := r.ReadByte()
-				if err != nil {
-					log.Warn("Could not decode chunk type:", err)
-					p.dirty = true
-					return sm, chunksToPersist, nil
-				}
-				chunk := newChunkForEncoding(chunkEncoding(encoding))
-				if err := chunk.unmarshal(r); err != nil {
-					log.Warn("Could not decode chunk:", err)
-					p.dirty = true
-					return sm, chunksToPersist, nil
-				}
-				cd := newChunkDesc(chunk, chunk.firstTime())
-				if i < numChunkDescs-1 {
-					// This is NOT the head chunk. So it's a chunk
-					// to be persisted, and we need to populate lastTime.
-					chunksToPersist++
-					cd.maybePopulateLastTime()
-				}
-				chunkDescs[i] = cd
-			}
-		}
-
-		fingerprintToSeries[model.Fingerprint(fp)] = &memorySeries{
-			metric:           model.Metric(metric),
-			chunkDescs:       chunkDescs,
-			persistWatermark: int(persistWatermark),
-			modTime:          modTime,
-			chunkDescsOffset: int(chunkDescsOffset),
-			savedFirstTime:   model.Time(savedFirstTime),
-			lastTime:         chunkDescs[len(chunkDescs)-1].lastTime(),
-			headChunkClosed:  headChunkClosed,
-		}
-	}
-	return sm, chunksToPersist, nil
+	return sm, hs.chunksToPersistTotal, nil
 }
 
 // dropAndPersistChunks deletes all chunks from a series file whose last sample

storage/local/storagetool/main.go

@@ -0,0 +1,76 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strings"
+	"text/template"
+
+	"github.com/prometheus/prometheus/util/cli"
+	"github.com/prometheus/prometheus/version"
+
+	"github.com/prometheus/prometheus/storage/local"
+)
+
+// DumpHeadsCmd dumps metadata of a heads.db file.
+func DumpHeadsCmd(t cli.Term, args ...string) int {
+	if len(args) != 1 {
+		t.Infof("usage: storagetool dump-heads <file>")
+		return 2
+	}
+	if err := local.DumpHeads(args[0], t.Out()); err != nil {
+		t.Errorf("  FAILED: %s", err)
+		return 1
+	}
+	return 0
+}
+
+var versionInfoTmpl = `
+prometheus, version {{.version}} (branch: {{.branch}}, revision: {{.revision}})
+  build user:       {{.buildUser}}
+  build date:       {{.buildDate}}
+  go version:       {{.goVersion}}
+`
+
+// VersionCmd prints the binaries version information.
+func VersionCmd(t cli.Term, _ ...string) int {
+	tmpl := template.Must(template.New("version").Parse(versionInfoTmpl))
+
+	var buf bytes.Buffer
+	if err := tmpl.ExecuteTemplate(&buf, "version", version.Map); err != nil {
+		panic(err)
+	}
+	fmt.Fprintln(t.Out(), strings.TrimSpace(buf.String()))
+	return 0
+}
+
+func main() {
+	app := cli.NewApp("storagetool")
+
+	app.Register("dump-heads", &cli.Command{
+		Desc: "dump metadata of a heads.db checkpoint file",
+		Run:  DumpHeadsCmd,
+	})
+
+	app.Register("version", &cli.Command{
+		Desc: "print the version of this binary",
+		Run:  VersionCmd,
+	})
+
+	t := cli.BasicTerm(os.Stdout, os.Stderr)
+	os.Exit(app.Run(t, os.Args[1:]...))
+}

util/cli/cli.go

@@ -32,7 +32,8 @@ type Command struct {
 type Term interface {
 	Infof(format string, v ...interface{})
 	Errorf(format string, v ...interface{})
-	Out(format string)
+	Out() io.Writer
+	Err() io.Writer
 }
 
 type basicTerm struct {
@@ -52,9 +53,13 @@ func (t *basicTerm) Errorf(format string, v ...interface{}) {
 }
 
 // Out implements Term.
-func (t *basicTerm) Out(msg string) {
-	fmt.Fprint(t.out, msg)
-	fmt.Fprint(t.out, "\n")
+func (t *basicTerm) Out() io.Writer {
+	return t.out
+}
+
+// Err implements Term.
+func (t *basicTerm) Err() io.Writer {
+	return t.err
 }
 
 // BasicTerm returns a Term writing Infof and Errorf to err and Out to out.

version/VERSION

@@ -1 +1 @@
-0.17.0rc2
+0.17.0

web/ui/bindata.go

@@ -159,7 +159,7 @@ func webUiTemplatesGraphHtml() (*asset, error) {
 	return a, nil
 }
 
-var _webUiTemplatesStatusHtml = []byte("\x1f\x8b\x08\x00\x00\x09\x6e\x88\x00\xff\xcc\x57\xcd\x6e\xdc\x36\x10\xbe\xef\x53\xb0\x44\x8e\xd5\x2e\x10\xa0\x17\x63\x57\x07\x1b\x29\x1c\xc0\x29\xdc\xac\x7d\xe9\x25\xe0\x8a\xb3\x12\x5b\x9a\x14\x48\xca\xb5\xa1\xe8\xdd\x3b\x43\x49\x5e\xfd\x6d\x9a\x34\x68\xeb\xcb\x9a\x43\x0e\xe7\xe7\x9b\x6f\x46\x74\x5d\x4b\x38\x2a\x03\x8c\x17\x20\x24\x6f\x9a\xed\x0f\x49\xc2\x8c\x7a\x62\x49\x92\xd6\x35\x18\xd9\x34\xab\xd5\x49\x2b\xb3\x26\x80\x09\xa8\xb8\x62\x6c\x2b\xd5\x23\xcb\xb4\xf0\x7e\x17\x0f\x04\xaa\xb8\xe4\xa8\x2b\x25\x79\x8a\xe7\xa8\x51\xbc\x65\x4a\xee\xb8\xab\x4c\x50\x0f\xc0\xd3\x8f\xed\x82\xbd\x37\x47\xeb\x1e\x44\x50\xd6\x6c\x37\xc5\xdb\x4e\x3b\x88\x83\x86\xde\x62\x2b\xc4\xdf\x04\xad\x4b\x30\x1e\x64\x27\x1f\xac\x93\xe0\x5e\x44\x1f\x9c\x2a\x5f\xa4\xc2\x3e\x82\xeb\x02\x20\xa3\x07\x2b\x9f\x7b\x89\x64\x77\x12\x48\x2c\xd2\xfb\x92\x62\xda\x6e\x70\x39\x3a\x91\x88\xc0\x7a\x1f\x44\xa8\xfc\xfa\x52\xb9\x50\xac\xef\xef\xae\x10\xa2\x0d\x9e\x9c\xec\x6d\x4e\x06\x71\x7d\x72\x86\x02\x85\x93\xae\x46\x48\x1c\x2a\xa5\xa5\x3a\x65\xcf\xd3\x4b\xda\xf9\x1f\x01\xa9\x6b\x27\x4c\x0e\xec\xcd\x1f\xf0\xfc\x23\x7b\xf3\x28\x74\x05\xec\x62\xc7\xd6\x14\x52\xac\xf3\x39\xe0\x98\xcf\x6c\x09\x58\x5d\xfb\x27\x47\xa8\xc8\x40\x44\x67\x01\xc6\xd6\xec\x97\xb0\xa3\x40\x5a\xba\x7d\x35\x96\x08\xc2\x51\xe5\x95\xeb\x80\xbc\x1a\x8a\x03\x10\x4b\x07\x83\x42\xb6\x5a\x14\x09\xed\xaf\x26\x34\xd5\xe0\x89\xa4\xf8\x67\x66\xa0\x45\x29\x13\x5a\xb3\xde\x56\x54\x6c\x1a\x34\x7e\x7d\xf7\xe1\x66\x6f\x54\x59\x42\x60\xa5\x08\xc5\xad\xc3\x86\x79\x42\x2f\x07\xb7\xe9\xfb\x68\xc9\x63\x10\x2e\x87\x80\x3e\xef\xda\xc5\xc9\xeb\xbf\x54\xfd\x41\xbd\x7f\xb7\x07\xac\x77\x69\xad\xa6\x72\x8f\x12\x6b\xa3\xb9\xc5\x23\x3f\x60\x40\x2c\x3a\x8e\x89\x61\x79\x5b\x5e\x10\x19\x32\x54\x2e\x85\xd9\xf1\x9f\x78\x1f\x33\x7a\xf8\x44\x17\xc8\x3f\x72\x00\xc5\x8e\x1f\xe3\xc2\x2f\xb0\xab\x73\x96\xbe\x33\xb2\xb4\xca\x84\x29\xab\xfa\x73\x8a\x77\xd6\xb9\xfd\xe1\x8d\x38\x80\xf6\xe7\x4f\x7d\x60\xfb\xcc\x89\xf2\xac\x81\x77\xce\x59\x37\x3f\x9c\x46\x4f\x1a\x13\x58\xa6\x4d\x36\x80\x9d\x00\x1f\x81\x7a\x26\x79\x39\xdb\x12\xac\x40\x5a\xed\x38\xf2\xed\xfe\xe3\x0d\xfb\xcc\x72\x6d\x0f\x42\xe3\xba\x69\x08\x60\xda\x5d\xef\xb3\x02\x1e\xb0\xd3\x2e\x36\x9b\x6e\xe7\xda\xfa\x10\x49\x4a\xc2\x2d\x92\x93\x8a\x20\x52\xa4\xe6\xd4\xc3\x20\x4a\x4d\xd8\xf5\xe3\xc0\xc7\x79\x40\xd7\x7f\xad\xc0\x3d\xb3\x49\xf8\x93\xab\x6a\x38\x45\x3a\x03\x8b\x37\x30\x25\x62\x4c\xcf\x96\xe8\x92\xc5\xdf\xa4\x74\xea\x41\xb8\xe7\x48\x9b\xb8\xd3\x34\x94\x77\x3f\x46\xf8\x76\x43\x37\xe7\xf1\x4f\xa7\xc8\xdf\xed\x8f\xe7\xd1\x59\xe8\x27\x91\x0a\x0d\x2e\xb0\xf8\x9b\xd4\xf5\x4b\xd7\x5c\x83\xd0\xd8\x08\x9f\x59\x11\x17\x77\xf6\x8a\xd4\x11\x2d\xe6\x89\xa6\x9f\x94\x91\x2a\x13\xc1\x3a\x16\xe0\x29\x24\x15\x4e\x0b\x97\x09\x0f\x7c\x39\x8f\xb1\xd9\x85\x94\x96\x41\xf8\x67\x29\x65\x95\xf3\xd6\x25\xb1\xd9\xb0\x5d\x99\x14\x41\x24\xc1\xe6\xb9\xc6\x01\x1f\x90\xb2\x41\x95\x9c\x05\x15\x48\xee\x8e\xad\x53\xb9\x32\x42\x27\xdd\xf6\x25\xe0\x37\x0c\x98\x83\x58\x31\x65\xf2\x0b\xca\xe2\x03\x04\xd1\x76\x22\xb1\x74\x31\xd3\xb6\xc4\x91\x65\x71\x76\xb5\xea\x6c\xdd\xfd\xa5\x39\xc2\x19\x57\x06\x61\x34\x19\xf0\x2f\xd3\x6f\xc4\xdc\x48\x41\xdd\x79\xff\x0f\x29\xa8\x3d\x7c\xab\x3f\x7c\x62\x89\x4a\x07\x9e\x1a\x6b\xe0\xdb\xf9\xfd\x9d\x64\xa8\x6b\x75\x7c\x21\x32\x8d\xc6\x76\x32\xae\xdf\xfb\xdf\xc0\xe1\x33\xe0\x17\xc0\xaf\x48\x9f\x58\x5d\x7b\x85\x85\x58\xd0\x47\xae\x8b\xdc\x7e\x67\xaf\xcd\x62\x89\x73\x78\x29\xe7\x73\x4d\x29\x89\x0a\x6e\xda\x76\x7c\xf0\x0c\x18\x98\x3d\x87\xf5\xd7\x66\x31\xfd\x1c\xcc\xef\x8d\xde\x32\x73\x95\xe5\xd7\x0d\x06\xef\x42\x55\x1e\xb5\xc8\xf1\x7d\xb0\x6f\x25\xf6\x33\x89\xaf\xe5\x85\xd8\x61\x19\x63\x7a\x6d\x2f\x45\x5a\xe2\xff\x27\xe9\xaa\x57\xfe\x2b\x00\x00\xff\xff\xb2\x36\x91\x1f\xeb\x0c\x00\x00")
+var _webUiTemplatesStatusHtml = []byte("\x1f\x8b\x08\x00\x00\x09\x6e\x88\x00\xff\xcc\x57\xcd\x6e\xdc\x36\x10\xbe\xef\x53\xb0\x44\x8e\xd5\x2e\x10\xa0\x17\x63\x57\x07\x1b\x29\x1c\xc0\x29\xdc\xac\x7d\xe9\x25\xe0\x8a\xb3\x12\x5b\x9a\x14\x48\xca\xf5\x42\xd1\xbb\x77\x86\x92\xa2\x9f\xd5\xa6\x49\x83\xb6\xb9\xac\x39\xe4\x70\x7e\xbe\xf9\x66\x44\xd7\xb5\x84\xa3\x32\xc0\x78\x01\x42\xf2\xa6\xd9\xfe\x90\x24\xcc\xa8\x17\x96\x24\x69\x5d\x83\x91\x4d\xb3\x5a\x0d\x5a\x99\x35\x01\x4c\x40\xc5\x15\x63\x5b\xa9\x9e\x59\xa6\x85\xf7\xbb\x78\x20\x50\xc5\x25\x47\x5d\x29\xc9\x53\x3c\x47\x8d\xe2\x35\x53\x72\xc7\x5d\x65\x82\x7a\x02\x9e\xbe\x6f\x17\xec\xad\x39\x5a\xf7\x24\x82\xb2\x66\xbb\x29\x5e\x77\xda\x41\x1c\x34\xf4\x16\x5b\x21\xfe\x26\x68\x5d\x82\xf1\x20\x3b\xf9\x60\x9d\x04\xf7\x49\xf4\xc1\xa9\xf2\x93\x54\xd8\x67\x70\x5d\x00\x64\xf4\x60\xe5\xa9\x97\x48\x76\x83\x40\x62\x91\x3e\x96\x14\xd3\x76\x83\xcb\xc9\x89\x44\x04\xd6\xfb\x20\x42\xe5\xd7\xd7\xca\x85\x62\xfd\xf8\x70\x83\x10\x6d\xf0\x64\xb0\xb7\x19\x0c\xe2\x7a\x70\x86\x02\x85\x93\xae\x26\x48\x1c\x2a\xa5\xa5\x1a\xb2\xe7\xe9\x35\xed\xfc\x8f\x80\xd4\xb5\x13\x26\x07\xf6\xea\x0f\x38\xfd\xc8\x5e\x3d\x0b\x5d\x01\xbb\xda\xb1\x35\x85\x14\xeb\x7c\x09\x38\xe6\x33\x5b\x02\x56\xd7\xfe\xc9\x11\x2a\x32\x10\xd1\x59\x80\xb1\x35\xfb\x39\xec\x28\x90\x96\x6e\x5f\x8c\x25\x82\x70\x54\x79\xe5\x3a\x20\x6f\xc6\xe2\x08\xc4\xd2\xc1\xa8\x90\xad\x16\x45\x42\xfb\xab\x19\x4d\x35\x78\x22\x29\xfe\x39\x33\xd0\xa2\x94\x09\xad\x59\x6f\x2b\x2a\x36\x0d\x1a\xbf\x7d\x78\x77\xb7\x37\xaa\x2c\x21\xb0\x52\x84\xe2\xde\x61\xc3\xbc\xa0\x97\x83\xdb\xf4\x7d\xb4\xe4\x31\x08\x97\x43\x40\x9f\x0f\xed\x62\xf0\xfa\x2f\x55\x7f\x54\xef\xdf\xed\x01\xeb\x5d\x5a\xab\xa9\xdc\x93\xc4\xda\x68\xee\xf1\xc8\x8f\x18\x10\x8b\x8e\x63\x62\x5c\xde\x96\x17\x44\x86\x0c\x95\x4b\x61\x76\xfc\x27\xde\xc7\x8c\x1e\x3e\xd0\x05\xf2\x8f\x1c\x40\xb1\xe3\xc7\xb4\xf0\x0b\xec\xea\x9c\xa5\x6f\x8c\x2c\xad\x32\x61\xce\xaa\xfe\x9c\xe2\x3d\xeb\xdc\xfe\xf0\x4e\x1c\x40\xfb\xcb\xa7\x3e\xb0\x7d\xe6\x44\x79\xd1\xc0\x1b\xe7\xac\x3b\x3f\x9c\x47\x4f\x1a\x33\x58\xe6\x4d\x36\x82\x9d\x00\x9f\x80\x7a\x21\x79\x79\xb6\x25\x58\x81\xb4\xda\x71\xe4\xdb\xe3\xfb\x3b\xf6\x91\xe5\xda\x1e\x84\xc6\x75\xd3\x10\xc0\xb4\xbb\xde\x67\x05\x3c\x61\xa7\x5d\x6d\x36\xdd\xce\xad\xf5\x21\x92\x94\x84\x7b\x24\x27\x15\x41\xa4\x48\xcd\xb9\x87\x51\x94\x9a\xb0\xeb\xc7\x81\x8f\xf3\x80\xae\xff\x5a\x81\x3b\xb1\x59\xf8\xb3\xab\x6a\x3c\x45\x3a\x03\x8b\x37\x30\x25\x62\x4c\xcf\x96\xe8\x92\xc5\xdf\xa4\x74\xea\x49\xb8\x53\xa4\x4d\xdc\x69\x1a\xca\xbb\x1f\x23\x7c\xbb\xa1\x9b\xe7\xf1\xcf\xa7\xc8\xdf\xed\x4f\xe7\xd1\x45\xe8\x67\x91\x0a\x0d\x2e\xb0\xf8\x9b\xd4\x35\x5b\xdf\x82\xd0\xd8\x01\x1f\x59\x11\x17\x0f\xf6\x86\xf4\x10\x26\xe6\x89\x9f\x1f\x94\x91\x2a\x13\xc1\x3a\x16\xe0\x25\x24\x15\x8e\x09\x97\x09\x0f\x7c\x39\x81\xce\xde\x42\x12\xcb\x69\xff\xb3\x24\xb2\xca\x79\xeb\x92\xd8\x5e\xd8\xa0\x4c\x8a\x20\x92\x60\xf3\x5c\xe3\x48\x0f\x48\xd2\xa0\x4a\xce\x82\x0a\x24\x77\xc7\xd6\xa9\x5c\x19\xa1\x93\x6e\xfb\x1a\xf0\xab\x05\xcc\x41\xac\x91\x32\xf9\x15\x85\xff\x0e\x82\x68\x7b\x8f\x78\xb9\x98\x62\x5b\xd4\xc8\xab\x38\xad\x5a\x75\xb6\xee\xfe\xd2\xe4\xe0\x8c\x2b\x83\xf8\x99\x0c\xf8\xe7\x09\x37\xe1\x6a\x24\x9d\xee\xbc\xff\x87\xa4\xd3\x1e\xbe\xd6\x1f\x3e\xaa\x44\xa5\x03\x4f\x8d\x35\xf0\xf5\x8c\xfe\x46\x32\xd4\xb5\x3a\x12\xe0\x3e\xb4\x43\x70\xfd\xd6\xff\x06\x0e\xbf\xf8\xbf\x00\x7e\x30\xfa\x8c\xea\xda\x2b\xac\xc0\x58\x11\x69\x2d\x72\xfb\x8d\xfd\x34\x78\x8f\x43\x76\x29\xbd\x4b\x1d\x27\xa9\xea\x6e\xde\x5a\x71\x00\x8e\xec\x5d\xc2\xf3\x4b\xe3\x9e\x0f\xf9\xf3\x7b\x93\x17\xca\xb9\xca\xf2\x9b\x05\xa3\x76\xa1\x2a\x8f\x5a\xe4\xf8\xd5\xdf\xb7\x12\xfb\x99\xc4\xef\xe5\xdd\xd7\xbd\x01\x62\x4c\xdf\xdb\xfb\x8f\x96\xf8\x5f\x47\xba\xea\x95\xff\x0a\x00\x00\xff\xff\xd0\x50\xb7\x0a\xc1\x0c\x00\x00")
 
 func webUiTemplatesStatusHtmlBytes() ([]byte, error) {
 	return bindataRead(
@@ -174,7 +174,7 @@ func webUiTemplatesStatusHtml() (*asset, error) {
 		return nil, err
 	}
 
-	info := bindataFileInfo{name: "web/ui/templates/status.html", size: 3307, mode: os.FileMode(420), modTime: time.Unix(1455530985, 0)}
+	info := bindataFileInfo{name: "web/ui/templates/status.html", size: 3265, mode: os.FileMode(420), modTime: time.Unix(1456687049, 0)}
 	a := &asset{bytes: bytes, info: info}
 	return a, nil
 }

web/ui/templates/status.html

@@ -55,8 +55,8 @@
                 {{end}}
               </td>
               <td>
-                <span class="alert alert-{{ .Status.Health | healthToClass }} state_indicator text-uppercase">
-                  {{.Status.Health}}
+                <span class="alert alert-{{ .Health | healthToClass }} state_indicator text-uppercase">
+                  {{.Health}}
                 </span>
               </td>
               <td>
@@ -70,11 +70,11 @@
                 </span>
               </td>
               <td>
-                {{if .Status.LastScrape.IsZero}}Never{{else}}{{since .Status.LastScrape}} ago{{end}}
+                {{if .LastScrape.IsZero}}Never{{else}}{{since .LastScrape}} ago{{end}}
               </td>
               <td>
-                {{if .Status.LastError}}
-                <span class="alert alert-danger state_indicator">{{.Status.LastError}}</span>
+                {{if .LastError}}
+                <span class="alert alert-danger state_indicator">{{.LastError}}</span>
                 {{end}}
               </td>
             </tr>