prometheus/scrape/scrape.go
Bryan Boreham 1e3fef6ab0
scraping: limit detail on dropped targets, to save memory (#12647)
It's possible (quite common on Kubernetes) to have a service discovery
return thousands of targets then drop most of them in relabel rules.
The main place this data is used is to display in the web UI, where
you don't want thousands of lines of display.

The new limit is `keep_dropped_targets`, which defaults to 0
for backwards-compatibility.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2023-08-14 15:39:25 +01:00

1982 lines
58 KiB
Go

// 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 scrape
import (
"bufio"
"bytes"
"compress/gzip"
"context"
"fmt"
"io"
"math"
"net/http"
"reflect"
"strconv"
"sync"
"time"
"github.com/go-kit/log"
"github.com/go-kit/log/level"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
config_util "github.com/prometheus/common/config"
"github.com/prometheus/common/model"
"github.com/prometheus/common/version"
"golang.org/x/exp/slices"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/discovery/targetgroup"
"github.com/prometheus/prometheus/model/exemplar"
"github.com/prometheus/prometheus/model/histogram"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/model/metadata"
"github.com/prometheus/prometheus/model/relabel"
"github.com/prometheus/prometheus/model/textparse"
"github.com/prometheus/prometheus/model/timestamp"
"github.com/prometheus/prometheus/model/value"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/util/pool"
)
// ScrapeTimestampTolerance is the tolerance for scrape appends timestamps
// alignment, to enable better compression at the TSDB level.
// See https://github.com/prometheus/prometheus/issues/7846
var ScrapeTimestampTolerance = 2 * time.Millisecond
// AlignScrapeTimestamps enables the tolerance for scrape appends timestamps described above.
var AlignScrapeTimestamps = true
var errNameLabelMandatory = fmt.Errorf("missing metric name (%s label)", labels.MetricName)
var (
targetIntervalLength = prometheus.NewSummaryVec(
prometheus.SummaryOpts{
Name: "prometheus_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"},
)
targetReloadIntervalLength = prometheus.NewSummaryVec(
prometheus.SummaryOpts{
Name: "prometheus_target_reload_length_seconds",
Help: "Actual interval to reload the scrape pool with a given configuration.",
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"},
)
targetScrapePools = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrape_pools_total",
Help: "Total number of scrape pool creation attempts.",
},
)
targetScrapePoolsFailed = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrape_pools_failed_total",
Help: "Total number of scrape pool creations that failed.",
},
)
targetScrapePoolReloads = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrape_pool_reloads_total",
Help: "Total number of scrape pool reloads.",
},
)
targetScrapePoolReloadsFailed = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrape_pool_reloads_failed_total",
Help: "Total number of failed scrape pool reloads.",
},
)
targetScrapePoolExceededTargetLimit = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrape_pool_exceeded_target_limit_total",
Help: "Total number of times scrape pools hit the target limit, during sync or config reload.",
},
)
targetScrapePoolTargetLimit = prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Name: "prometheus_target_scrape_pool_target_limit",
Help: "Maximum number of targets allowed in this scrape pool.",
},
[]string{"scrape_job"},
)
targetScrapePoolTargetsAdded = prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Name: "prometheus_target_scrape_pool_targets",
Help: "Current number of targets in this scrape pool.",
},
[]string{"scrape_job"},
)
targetSyncIntervalLength = prometheus.NewSummaryVec(
prometheus.SummaryOpts{
Name: "prometheus_target_sync_length_seconds",
Help: "Actual interval to sync the scrape pool.",
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{"scrape_job"},
)
targetScrapePoolSyncsCounter = prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "prometheus_target_scrape_pool_sync_total",
Help: "Total number of syncs that were executed on a scrape pool.",
},
[]string{"scrape_job"},
)
targetScrapeExceededBodySizeLimit = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrapes_exceeded_body_size_limit_total",
Help: "Total number of scrapes that hit the body size limit",
},
)
targetScrapeSampleLimit = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrapes_exceeded_sample_limit_total",
Help: "Total number of scrapes that hit the sample limit and were rejected.",
},
)
targetScrapeSampleDuplicate = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrapes_sample_duplicate_timestamp_total",
Help: "Total number of samples rejected due to duplicate timestamps but different values.",
},
)
targetScrapeSampleOutOfOrder = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrapes_sample_out_of_order_total",
Help: "Total number of samples rejected due to not being out of the expected order.",
},
)
targetScrapeSampleOutOfBounds = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrapes_sample_out_of_bounds_total",
Help: "Total number of samples rejected due to timestamp falling outside of the time bounds.",
},
)
targetScrapeCacheFlushForced = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrapes_cache_flush_forced_total",
Help: "How many times a scrape cache was flushed due to getting big while scrapes are failing.",
},
)
targetScrapeExemplarOutOfOrder = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrapes_exemplar_out_of_order_total",
Help: "Total number of exemplar rejected due to not being out of the expected order.",
},
)
targetScrapePoolExceededLabelLimits = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrape_pool_exceeded_label_limits_total",
Help: "Total number of times scrape pools hit the label limits, during sync or config reload.",
},
)
targetSyncFailed = prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "prometheus_target_sync_failed_total",
Help: "Total number of target sync failures.",
},
[]string{"scrape_job"},
)
targetScrapeNativeHistogramBucketLimit = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_target_scrapes_exceeded_native_histogram_bucket_limit_total",
Help: "Total number of scrapes that hit the native histogram bucket limit and were rejected.",
},
)
)
func init() {
prometheus.MustRegister(
targetIntervalLength,
targetReloadIntervalLength,
targetScrapePools,
targetScrapePoolsFailed,
targetScrapePoolReloads,
targetScrapePoolReloadsFailed,
targetSyncIntervalLength,
targetScrapePoolSyncsCounter,
targetScrapeExceededBodySizeLimit,
targetScrapeSampleLimit,
targetScrapeSampleDuplicate,
targetScrapeSampleOutOfOrder,
targetScrapeSampleOutOfBounds,
targetScrapePoolExceededTargetLimit,
targetScrapePoolTargetLimit,
targetScrapePoolTargetsAdded,
targetScrapeCacheFlushForced,
targetMetadataCache,
targetScrapeExemplarOutOfOrder,
targetScrapePoolExceededLabelLimits,
targetSyncFailed,
targetScrapeNativeHistogramBucketLimit,
)
}
// scrapePool manages scrapes for sets of targets.
type scrapePool struct {
appendable storage.Appendable
logger log.Logger
cancel context.CancelFunc
httpOpts []config_util.HTTPClientOption
// mtx must not be taken after targetMtx.
mtx sync.Mutex
config *config.ScrapeConfig
client *http.Client
loops map[uint64]loop
targetMtx sync.Mutex
// activeTargets and loops must always be synchronized to have the same
// set of hashes.
activeTargets map[uint64]*Target
droppedTargets []*Target // Subject to KeepDroppedTargets limit.
droppedTargetsCount int // Count of all dropped targets.
// Constructor for new scrape loops. This is settable for testing convenience.
newLoop func(scrapeLoopOptions) loop
noDefaultPort bool
enableProtobufNegotiation bool
}
type labelLimits struct {
labelLimit int
labelNameLengthLimit int
labelValueLengthLimit int
}
type scrapeLoopOptions struct {
target *Target
scraper scraper
sampleLimit int
bucketLimit int
labelLimits *labelLimits
honorLabels bool
honorTimestamps bool
interval time.Duration
timeout time.Duration
scrapeClassicHistograms bool
mrc []*relabel.Config
cache *scrapeCache
}
const maxAheadTime = 10 * time.Minute
// returning an empty label set is interpreted as "drop"
type labelsMutator func(labels.Labels) labels.Labels
func newScrapePool(cfg *config.ScrapeConfig, app storage.Appendable, offsetSeed uint64, logger log.Logger, options *Options) (*scrapePool, error) {
targetScrapePools.Inc()
if logger == nil {
logger = log.NewNopLogger()
}
client, err := config_util.NewClientFromConfig(cfg.HTTPClientConfig, cfg.JobName, options.HTTPClientOptions...)
if err != nil {
targetScrapePoolsFailed.Inc()
return nil, errors.Wrap(err, "error creating HTTP client")
}
buffers := pool.New(1e3, 100e6, 3, func(sz int) interface{} { return make([]byte, 0, sz) })
ctx, cancel := context.WithCancel(context.Background())
sp := &scrapePool{
cancel: cancel,
appendable: app,
config: cfg,
client: client,
activeTargets: map[uint64]*Target{},
loops: map[uint64]loop{},
logger: logger,
httpOpts: options.HTTPClientOptions,
noDefaultPort: options.NoDefaultPort,
enableProtobufNegotiation: options.EnableProtobufNegotiation,
}
sp.newLoop = func(opts scrapeLoopOptions) loop {
// Update the targets retrieval function for metadata to a new scrape cache.
cache := opts.cache
if cache == nil {
cache = newScrapeCache()
}
opts.target.SetMetadataStore(cache)
return newScrapeLoop(
ctx,
opts.scraper,
log.With(logger, "target", opts.target),
buffers,
func(l labels.Labels) labels.Labels {
return mutateSampleLabels(l, opts.target, opts.honorLabels, opts.mrc)
},
func(l labels.Labels) labels.Labels { return mutateReportSampleLabels(l, opts.target) },
func(ctx context.Context) storage.Appender { return app.Appender(ctx) },
cache,
offsetSeed,
opts.honorTimestamps,
opts.sampleLimit,
opts.bucketLimit,
opts.labelLimits,
opts.interval,
opts.timeout,
opts.scrapeClassicHistograms,
options.ExtraMetrics,
options.EnableMetadataStorage,
opts.target,
options.PassMetadataInContext,
)
}
targetScrapePoolTargetLimit.WithLabelValues(sp.config.JobName).Set(float64(sp.config.TargetLimit))
return sp, nil
}
func (sp *scrapePool) ActiveTargets() []*Target {
sp.targetMtx.Lock()
defer sp.targetMtx.Unlock()
var tActive []*Target
for _, t := range sp.activeTargets {
tActive = append(tActive, t)
}
return tActive
}
// Return dropped targets, subject to KeepDroppedTargets limit.
func (sp *scrapePool) DroppedTargets() []*Target {
sp.targetMtx.Lock()
defer sp.targetMtx.Unlock()
return sp.droppedTargets
}
func (sp *scrapePool) DroppedTargetsCount() int {
sp.targetMtx.Lock()
defer sp.targetMtx.Unlock()
return sp.droppedTargetsCount
}
// stop terminates all scrape loops and returns after they all terminated.
func (sp *scrapePool) stop() {
sp.mtx.Lock()
defer sp.mtx.Unlock()
sp.cancel()
var wg sync.WaitGroup
sp.targetMtx.Lock()
for fp, l := range sp.loops {
wg.Add(1)
go func(l loop) {
l.stop()
wg.Done()
}(l)
delete(sp.loops, fp)
delete(sp.activeTargets, fp)
}
sp.targetMtx.Unlock()
wg.Wait()
sp.client.CloseIdleConnections()
if sp.config != nil {
targetScrapePoolSyncsCounter.DeleteLabelValues(sp.config.JobName)
targetScrapePoolTargetLimit.DeleteLabelValues(sp.config.JobName)
targetScrapePoolTargetsAdded.DeleteLabelValues(sp.config.JobName)
targetSyncIntervalLength.DeleteLabelValues(sp.config.JobName)
targetSyncFailed.DeleteLabelValues(sp.config.JobName)
}
}
// 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 stopped scraping.
func (sp *scrapePool) reload(cfg *config.ScrapeConfig) error {
sp.mtx.Lock()
defer sp.mtx.Unlock()
targetScrapePoolReloads.Inc()
start := time.Now()
client, err := config_util.NewClientFromConfig(cfg.HTTPClientConfig, cfg.JobName, sp.httpOpts...)
if err != nil {
targetScrapePoolReloadsFailed.Inc()
return errors.Wrap(err, "error creating HTTP client")
}
reuseCache := reusableCache(sp.config, cfg)
sp.config = cfg
oldClient := sp.client
sp.client = client
targetScrapePoolTargetLimit.WithLabelValues(sp.config.JobName).Set(float64(sp.config.TargetLimit))
var (
wg sync.WaitGroup
interval = time.Duration(sp.config.ScrapeInterval)
timeout = time.Duration(sp.config.ScrapeTimeout)
bodySizeLimit = int64(sp.config.BodySizeLimit)
sampleLimit = int(sp.config.SampleLimit)
bucketLimit = int(sp.config.NativeHistogramBucketLimit)
labelLimits = &labelLimits{
labelLimit: int(sp.config.LabelLimit),
labelNameLengthLimit: int(sp.config.LabelNameLengthLimit),
labelValueLengthLimit: int(sp.config.LabelValueLengthLimit),
}
honorLabels = sp.config.HonorLabels
honorTimestamps = sp.config.HonorTimestamps
mrc = sp.config.MetricRelabelConfigs
)
sp.targetMtx.Lock()
forcedErr := sp.refreshTargetLimitErr()
for fp, oldLoop := range sp.loops {
var cache *scrapeCache
if oc := oldLoop.getCache(); reuseCache && oc != nil {
oldLoop.disableEndOfRunStalenessMarkers()
cache = oc
} else {
cache = newScrapeCache()
}
t := sp.activeTargets[fp]
interval, timeout, err := t.intervalAndTimeout(interval, timeout)
acceptHeader := scrapeAcceptHeader
if sp.enableProtobufNegotiation {
acceptHeader = scrapeAcceptHeaderWithProtobuf
}
var (
s = &targetScraper{Target: t, client: sp.client, timeout: timeout, bodySizeLimit: bodySizeLimit, acceptHeader: acceptHeader}
newLoop = sp.newLoop(scrapeLoopOptions{
target: t,
scraper: s,
sampleLimit: sampleLimit,
bucketLimit: bucketLimit,
labelLimits: labelLimits,
honorLabels: honorLabels,
honorTimestamps: honorTimestamps,
mrc: mrc,
cache: cache,
interval: interval,
timeout: timeout,
})
)
if err != nil {
newLoop.setForcedError(err)
}
wg.Add(1)
go func(oldLoop, newLoop loop) {
oldLoop.stop()
wg.Done()
newLoop.setForcedError(forcedErr)
newLoop.run(nil)
}(oldLoop, newLoop)
sp.loops[fp] = newLoop
}
sp.targetMtx.Unlock()
wg.Wait()
oldClient.CloseIdleConnections()
targetReloadIntervalLength.WithLabelValues(interval.String()).Observe(
time.Since(start).Seconds(),
)
return nil
}
// Sync converts target groups into actual scrape targets and synchronizes
// the currently running scraper with the resulting set and returns all scraped and dropped targets.
func (sp *scrapePool) Sync(tgs []*targetgroup.Group) {
sp.mtx.Lock()
defer sp.mtx.Unlock()
start := time.Now()
sp.targetMtx.Lock()
var all []*Target
var targets []*Target
lb := labels.NewBuilder(labels.EmptyLabels())
sp.droppedTargets = []*Target{}
sp.droppedTargetsCount = 0
for _, tg := range tgs {
targets, failures := TargetsFromGroup(tg, sp.config, sp.noDefaultPort, targets, lb)
for _, err := range failures {
level.Error(sp.logger).Log("msg", "Creating target failed", "err", err)
}
targetSyncFailed.WithLabelValues(sp.config.JobName).Add(float64(len(failures)))
for _, t := range targets {
// Replicate .Labels().IsEmpty() with a loop here to avoid generating garbage.
nonEmpty := false
t.LabelsRange(func(l labels.Label) { nonEmpty = true })
switch {
case nonEmpty:
all = append(all, t)
case !t.discoveredLabels.IsEmpty():
if sp.config.KeepDroppedTargets != 0 && uint(len(sp.droppedTargets)) < sp.config.KeepDroppedTargets {
sp.droppedTargets = append(sp.droppedTargets, t)
}
sp.droppedTargetsCount++
}
}
}
sp.targetMtx.Unlock()
sp.sync(all)
targetSyncIntervalLength.WithLabelValues(sp.config.JobName).Observe(
time.Since(start).Seconds(),
)
targetScrapePoolSyncsCounter.WithLabelValues(sp.config.JobName).Inc()
}
// 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) {
var (
uniqueLoops = make(map[uint64]loop)
interval = time.Duration(sp.config.ScrapeInterval)
timeout = time.Duration(sp.config.ScrapeTimeout)
bodySizeLimit = int64(sp.config.BodySizeLimit)
sampleLimit = int(sp.config.SampleLimit)
bucketLimit = int(sp.config.NativeHistogramBucketLimit)
labelLimits = &labelLimits{
labelLimit: int(sp.config.LabelLimit),
labelNameLengthLimit: int(sp.config.LabelNameLengthLimit),
labelValueLengthLimit: int(sp.config.LabelValueLengthLimit),
}
honorLabels = sp.config.HonorLabels
honorTimestamps = sp.config.HonorTimestamps
mrc = sp.config.MetricRelabelConfigs
scrapeClassicHistograms = sp.config.ScrapeClassicHistograms
)
sp.targetMtx.Lock()
for _, t := range targets {
hash := t.hash()
if _, ok := sp.activeTargets[hash]; !ok {
// The scrape interval and timeout labels are set to the config's values initially,
// so whether changed via relabeling or not, they'll exist and hold the correct values
// for every target.
var err error
interval, timeout, err = t.intervalAndTimeout(interval, timeout)
acceptHeader := scrapeAcceptHeader
if sp.enableProtobufNegotiation {
acceptHeader = scrapeAcceptHeaderWithProtobuf
}
s := &targetScraper{Target: t, client: sp.client, timeout: timeout, bodySizeLimit: bodySizeLimit, acceptHeader: acceptHeader}
l := sp.newLoop(scrapeLoopOptions{
target: t,
scraper: s,
sampleLimit: sampleLimit,
bucketLimit: bucketLimit,
labelLimits: labelLimits,
honorLabels: honorLabels,
honorTimestamps: honorTimestamps,
mrc: mrc,
interval: interval,
timeout: timeout,
scrapeClassicHistograms: scrapeClassicHistograms,
})
if err != nil {
l.setForcedError(err)
}
sp.activeTargets[hash] = t
sp.loops[hash] = l
uniqueLoops[hash] = l
} else {
// This might be a duplicated target.
if _, ok := uniqueLoops[hash]; !ok {
uniqueLoops[hash] = nil
}
// Need to keep the most updated labels information
// for displaying it in the Service Discovery web page.
sp.activeTargets[hash].SetDiscoveredLabels(t.DiscoveredLabels())
}
}
var wg sync.WaitGroup
// Stop and remove old targets and scraper loops.
for hash := range sp.activeTargets {
if _, ok := uniqueLoops[hash]; !ok {
wg.Add(1)
go func(l loop) {
l.stop()
wg.Done()
}(sp.loops[hash])
delete(sp.loops, hash)
delete(sp.activeTargets, hash)
}
}
sp.targetMtx.Unlock()
targetScrapePoolTargetsAdded.WithLabelValues(sp.config.JobName).Set(float64(len(uniqueLoops)))
forcedErr := sp.refreshTargetLimitErr()
for _, l := range sp.loops {
l.setForcedError(forcedErr)
}
for _, l := range uniqueLoops {
if l != nil {
go l.run(nil)
}
}
// 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()
}
// refreshTargetLimitErr returns an error that can be passed to the scrape loops
// if the number of targets exceeds the configured limit.
func (sp *scrapePool) refreshTargetLimitErr() error {
if sp.config == nil || sp.config.TargetLimit == 0 {
return nil
}
if l := len(sp.activeTargets); l > int(sp.config.TargetLimit) {
targetScrapePoolExceededTargetLimit.Inc()
return fmt.Errorf("target_limit exceeded (number of targets: %d, limit: %d)", l, sp.config.TargetLimit)
}
return nil
}
func verifyLabelLimits(lset labels.Labels, limits *labelLimits) error {
if limits == nil {
return nil
}
met := lset.Get(labels.MetricName)
if limits.labelLimit > 0 {
nbLabels := lset.Len()
if nbLabels > limits.labelLimit {
return fmt.Errorf("label_limit exceeded (metric: %.50s, number of labels: %d, limit: %d)", met, nbLabels, limits.labelLimit)
}
}
if limits.labelNameLengthLimit == 0 && limits.labelValueLengthLimit == 0 {
return nil
}
return lset.Validate(func(l labels.Label) error {
if limits.labelNameLengthLimit > 0 {
nameLength := len(l.Name)
if nameLength > limits.labelNameLengthLimit {
return fmt.Errorf("label_name_length_limit exceeded (metric: %.50s, label name: %.50s, length: %d, limit: %d)", met, l.Name, nameLength, limits.labelNameLengthLimit)
}
}
if limits.labelValueLengthLimit > 0 {
valueLength := len(l.Value)
if valueLength > limits.labelValueLengthLimit {
return fmt.Errorf("label_value_length_limit exceeded (metric: %.50s, label name: %.50s, value: %.50q, length: %d, limit: %d)", met, l.Name, l.Value, valueLength, limits.labelValueLengthLimit)
}
}
return nil
})
}
func mutateSampleLabels(lset labels.Labels, target *Target, honor bool, rc []*relabel.Config) labels.Labels {
lb := labels.NewBuilder(lset)
if honor {
target.LabelsRange(func(l labels.Label) {
if !lset.Has(l.Name) {
lb.Set(l.Name, l.Value)
}
})
} else {
var conflictingExposedLabels []labels.Label
target.LabelsRange(func(l labels.Label) {
existingValue := lset.Get(l.Name)
if existingValue != "" {
conflictingExposedLabels = append(conflictingExposedLabels, labels.Label{Name: l.Name, Value: existingValue})
}
// It is now safe to set the target label.
lb.Set(l.Name, l.Value)
})
if len(conflictingExposedLabels) > 0 {
resolveConflictingExposedLabels(lb, conflictingExposedLabels)
}
}
res := lb.Labels()
if len(rc) > 0 {
res, _ = relabel.Process(res, rc...)
}
return res
}
func resolveConflictingExposedLabels(lb *labels.Builder, conflictingExposedLabels []labels.Label) {
slices.SortStableFunc(conflictingExposedLabels, func(a, b labels.Label) bool {
return len(a.Name) < len(b.Name)
})
for _, l := range conflictingExposedLabels {
newName := l.Name
for {
newName = model.ExportedLabelPrefix + newName
if lb.Get(newName) == "" {
lb.Set(newName, l.Value)
break
}
}
}
}
func mutateReportSampleLabels(lset labels.Labels, target *Target) labels.Labels {
lb := labels.NewBuilder(lset)
target.LabelsRange(func(l labels.Label) {
lb.Set(model.ExportedLabelPrefix+l.Name, lset.Get(l.Name))
lb.Set(l.Name, l.Value)
})
return lb.Labels()
}
// appender returns an appender for ingested samples from the target.
func appender(app storage.Appender, sampleLimit, bucketLimit int) storage.Appender {
app = &timeLimitAppender{
Appender: app,
maxTime: timestamp.FromTime(time.Now().Add(maxAheadTime)),
}
// The sampleLimit is applied after metrics are potentially dropped via relabeling.
if sampleLimit > 0 {
app = &limitAppender{
Appender: app,
limit: sampleLimit,
}
}
if bucketLimit > 0 {
app = &bucketLimitAppender{
Appender: app,
limit: bucketLimit,
}
}
return app
}
// A scraper retrieves samples and accepts a status report at the end.
type scraper interface {
scrape(ctx context.Context, w io.Writer) (string, error)
Report(start time.Time, dur time.Duration, err error)
offset(interval time.Duration, offsetSeed uint64) time.Duration
}
// targetScraper implements the scraper interface for a target.
type targetScraper struct {
*Target
client *http.Client
req *http.Request
timeout time.Duration
gzipr *gzip.Reader
buf *bufio.Reader
bodySizeLimit int64
acceptHeader string
}
var errBodySizeLimit = errors.New("body size limit exceeded")
const (
scrapeAcceptHeader = `application/openmetrics-text;version=1.0.0,application/openmetrics-text;version=0.0.1;q=0.75,text/plain;version=0.0.4;q=0.5,*/*;q=0.1`
scrapeAcceptHeaderWithProtobuf = `application/vnd.google.protobuf;proto=io.prometheus.client.MetricFamily;encoding=delimited,application/openmetrics-text;version=1.0.0;q=0.8,application/openmetrics-text;version=0.0.1;q=0.75,text/plain;version=0.0.4;q=0.5,*/*;q=0.1`
)
var UserAgent = fmt.Sprintf("Prometheus/%s", version.Version)
func (s *targetScraper) scrape(ctx context.Context, w io.Writer) (string, error) {
if s.req == nil {
req, err := http.NewRequest("GET", s.URL().String(), nil)
if err != nil {
return "", err
}
req.Header.Add("Accept", s.acceptHeader)
req.Header.Add("Accept-Encoding", "gzip")
req.Header.Set("User-Agent", UserAgent)
req.Header.Set("X-Prometheus-Scrape-Timeout-Seconds", strconv.FormatFloat(s.timeout.Seconds(), 'f', -1, 64))
s.req = req
}
resp, err := s.client.Do(s.req.WithContext(ctx))
if err != nil {
return "", err
}
defer func() {
io.Copy(io.Discard, resp.Body)
resp.Body.Close()
}()
if resp.StatusCode != http.StatusOK {
return "", errors.Errorf("server returned HTTP status %s", resp.Status)
}
if s.bodySizeLimit <= 0 {
s.bodySizeLimit = math.MaxInt64
}
if resp.Header.Get("Content-Encoding") != "gzip" {
n, err := io.Copy(w, io.LimitReader(resp.Body, s.bodySizeLimit))
if err != nil {
return "", err
}
if n >= s.bodySizeLimit {
targetScrapeExceededBodySizeLimit.Inc()
return "", errBodySizeLimit
}
return resp.Header.Get("Content-Type"), nil
}
if s.gzipr == nil {
s.buf = bufio.NewReader(resp.Body)
s.gzipr, err = gzip.NewReader(s.buf)
if err != nil {
return "", err
}
} else {
s.buf.Reset(resp.Body)
if err = s.gzipr.Reset(s.buf); err != nil {
return "", err
}
}
n, err := io.Copy(w, io.LimitReader(s.gzipr, s.bodySizeLimit))
s.gzipr.Close()
if err != nil {
return "", err
}
if n >= s.bodySizeLimit {
targetScrapeExceededBodySizeLimit.Inc()
return "", errBodySizeLimit
}
return resp.Header.Get("Content-Type"), nil
}
// A loop can run and be stopped again. It must not be reused after it was stopped.
type loop interface {
run(errc chan<- error)
setForcedError(err error)
stop()
getCache() *scrapeCache
disableEndOfRunStalenessMarkers()
}
type cacheEntry struct {
ref storage.SeriesRef
lastIter uint64
hash uint64
lset labels.Labels
}
type scrapeLoop struct {
scraper scraper
l log.Logger
cache *scrapeCache
lastScrapeSize int
buffers *pool.Pool
offsetSeed uint64
honorTimestamps bool
forcedErr error
forcedErrMtx sync.Mutex
sampleLimit int
bucketLimit int
labelLimits *labelLimits
interval time.Duration
timeout time.Duration
scrapeClassicHistograms bool
appender func(ctx context.Context) storage.Appender
sampleMutator labelsMutator
reportSampleMutator labelsMutator
parentCtx context.Context
appenderCtx context.Context
ctx context.Context
cancel func()
stopped chan struct{}
disabledEndOfRunStalenessMarkers bool
reportExtraMetrics bool
appendMetadataToWAL bool
}
// scrapeCache tracks mappings of exposed metric strings to label sets and
// storage references. Additionally, it tracks staleness of series between
// scrapes.
type scrapeCache struct {
iter uint64 // Current scrape iteration.
// How many series and metadata entries there were at the last success.
successfulCount int
// Parsed string to an entry with information about the actual label set
// and its storage reference.
series map[string]*cacheEntry
// Cache of dropped metric strings and their iteration. The iteration must
// be a pointer so we can update it.
droppedSeries map[string]*uint64
// seriesCur and seriesPrev store the labels of series that were seen
// in the current and previous scrape.
// We hold two maps and swap them out to save allocations.
seriesCur map[uint64]labels.Labels
seriesPrev map[uint64]labels.Labels
metaMtx sync.Mutex
metadata map[string]*metaEntry
}
// metaEntry holds meta information about a metric.
type metaEntry struct {
metadata.Metadata
lastIter uint64 // Last scrape iteration the entry was observed at.
lastIterChange uint64 // Last scrape iteration the entry was changed at.
}
func (m *metaEntry) size() int {
// The attribute lastIter although part of the struct it is not metadata.
return len(m.Help) + len(m.Unit) + len(m.Type)
}
func newScrapeCache() *scrapeCache {
return &scrapeCache{
series: map[string]*cacheEntry{},
droppedSeries: map[string]*uint64{},
seriesCur: map[uint64]labels.Labels{},
seriesPrev: map[uint64]labels.Labels{},
metadata: map[string]*metaEntry{},
}
}
func (c *scrapeCache) iterDone(flushCache bool) {
c.metaMtx.Lock()
count := len(c.series) + len(c.droppedSeries) + len(c.metadata)
c.metaMtx.Unlock()
switch {
case flushCache:
c.successfulCount = count
case count > c.successfulCount*2+1000:
// If a target had varying labels in scrapes that ultimately failed,
// the caches would grow indefinitely. Force a flush when this happens.
// We use the heuristic that this is a doubling of the cache size
// since the last scrape, and allow an additional 1000 in case
// initial scrapes all fail.
flushCache = true
targetScrapeCacheFlushForced.Inc()
}
if flushCache {
// All caches may grow over time through series churn
// or multiple string representations of the same metric. Clean up entries
// that haven't appeared in the last scrape.
for s, e := range c.series {
if c.iter != e.lastIter {
delete(c.series, s)
}
}
for s, iter := range c.droppedSeries {
if c.iter != *iter {
delete(c.droppedSeries, s)
}
}
c.metaMtx.Lock()
for m, e := range c.metadata {
// Keep metadata around for 10 scrapes after its metric disappeared.
if c.iter-e.lastIter > 10 {
delete(c.metadata, m)
}
}
c.metaMtx.Unlock()
c.iter++
}
// Swap current and previous series.
c.seriesPrev, c.seriesCur = c.seriesCur, c.seriesPrev
// We have to delete every single key in the map.
for k := range c.seriesCur {
delete(c.seriesCur, k)
}
}
func (c *scrapeCache) get(met []byte) (*cacheEntry, bool) {
e, ok := c.series[string(met)]
if !ok {
return nil, false
}
e.lastIter = c.iter
return e, true
}
func (c *scrapeCache) addRef(met []byte, ref storage.SeriesRef, lset labels.Labels, hash uint64) {
if ref == 0 {
return
}
c.series[string(met)] = &cacheEntry{ref: ref, lastIter: c.iter, lset: lset, hash: hash}
}
func (c *scrapeCache) addDropped(met []byte) {
iter := c.iter
c.droppedSeries[string(met)] = &iter
}
func (c *scrapeCache) getDropped(met []byte) bool {
iterp, ok := c.droppedSeries[string(met)]
if ok {
*iterp = c.iter
}
return ok
}
func (c *scrapeCache) trackStaleness(hash uint64, lset labels.Labels) {
c.seriesCur[hash] = lset
}
func (c *scrapeCache) forEachStale(f func(labels.Labels) bool) {
for h, lset := range c.seriesPrev {
if _, ok := c.seriesCur[h]; !ok {
if !f(lset) {
break
}
}
}
}
func (c *scrapeCache) setType(metric []byte, t textparse.MetricType) {
c.metaMtx.Lock()
e, ok := c.metadata[string(metric)]
if !ok {
e = &metaEntry{Metadata: metadata.Metadata{Type: textparse.MetricTypeUnknown}}
c.metadata[string(metric)] = e
}
if e.Type != t {
e.Type = t
e.lastIterChange = c.iter
}
e.lastIter = c.iter
c.metaMtx.Unlock()
}
func (c *scrapeCache) setHelp(metric, help []byte) {
c.metaMtx.Lock()
e, ok := c.metadata[string(metric)]
if !ok {
e = &metaEntry{Metadata: metadata.Metadata{Type: textparse.MetricTypeUnknown}}
c.metadata[string(metric)] = e
}
if e.Help != string(help) {
e.Help = string(help)
e.lastIterChange = c.iter
}
e.lastIter = c.iter
c.metaMtx.Unlock()
}
func (c *scrapeCache) setUnit(metric, unit []byte) {
c.metaMtx.Lock()
e, ok := c.metadata[string(metric)]
if !ok {
e = &metaEntry{Metadata: metadata.Metadata{Type: textparse.MetricTypeUnknown}}
c.metadata[string(metric)] = e
}
if e.Unit != string(unit) {
e.Unit = string(unit)
e.lastIterChange = c.iter
}
e.lastIter = c.iter
c.metaMtx.Unlock()
}
func (c *scrapeCache) GetMetadata(metric string) (MetricMetadata, bool) {
c.metaMtx.Lock()
defer c.metaMtx.Unlock()
m, ok := c.metadata[metric]
if !ok {
return MetricMetadata{}, false
}
return MetricMetadata{
Metric: metric,
Type: m.Type,
Help: m.Help,
Unit: m.Unit,
}, true
}
func (c *scrapeCache) ListMetadata() []MetricMetadata {
c.metaMtx.Lock()
defer c.metaMtx.Unlock()
res := make([]MetricMetadata, 0, len(c.metadata))
for m, e := range c.metadata {
res = append(res, MetricMetadata{
Metric: m,
Type: e.Type,
Help: e.Help,
Unit: e.Unit,
})
}
return res
}
// MetadataSize returns the size of the metadata cache.
func (c *scrapeCache) SizeMetadata() (s int) {
c.metaMtx.Lock()
defer c.metaMtx.Unlock()
for _, e := range c.metadata {
s += e.size()
}
return s
}
// MetadataLen returns the number of metadata entries in the cache.
func (c *scrapeCache) LengthMetadata() int {
c.metaMtx.Lock()
defer c.metaMtx.Unlock()
return len(c.metadata)
}
func newScrapeLoop(ctx context.Context,
sc scraper,
l log.Logger,
buffers *pool.Pool,
sampleMutator labelsMutator,
reportSampleMutator labelsMutator,
appender func(ctx context.Context) storage.Appender,
cache *scrapeCache,
offsetSeed uint64,
honorTimestamps bool,
sampleLimit int,
bucketLimit int,
labelLimits *labelLimits,
interval time.Duration,
timeout time.Duration,
scrapeClassicHistograms bool,
reportExtraMetrics bool,
appendMetadataToWAL bool,
target *Target,
passMetadataInContext bool,
) *scrapeLoop {
if l == nil {
l = log.NewNopLogger()
}
if buffers == nil {
buffers = pool.New(1e3, 1e6, 3, func(sz int) interface{} { return make([]byte, 0, sz) })
}
if cache == nil {
cache = newScrapeCache()
}
appenderCtx := ctx
if passMetadataInContext {
// Store the cache and target in the context. This is then used by downstream OTel Collector
// to lookup the metadata required to process the samples. Not used by Prometheus itself.
// TODO(gouthamve) We're using a dedicated context because using the parentCtx caused a memory
// leak. We should ideally fix the main leak. See: https://github.com/prometheus/prometheus/pull/10590
appenderCtx = ContextWithMetricMetadataStore(appenderCtx, cache)
appenderCtx = ContextWithTarget(appenderCtx, target)
}
sl := &scrapeLoop{
scraper: sc,
buffers: buffers,
cache: cache,
appender: appender,
sampleMutator: sampleMutator,
reportSampleMutator: reportSampleMutator,
stopped: make(chan struct{}),
offsetSeed: offsetSeed,
l: l,
parentCtx: ctx,
appenderCtx: appenderCtx,
honorTimestamps: honorTimestamps,
sampleLimit: sampleLimit,
bucketLimit: bucketLimit,
labelLimits: labelLimits,
interval: interval,
timeout: timeout,
scrapeClassicHistograms: scrapeClassicHistograms,
reportExtraMetrics: reportExtraMetrics,
appendMetadataToWAL: appendMetadataToWAL,
}
sl.ctx, sl.cancel = context.WithCancel(ctx)
return sl
}
func (sl *scrapeLoop) run(errc chan<- error) {
select {
case <-time.After(sl.scraper.offset(sl.interval, sl.offsetSeed)):
// Continue after a scraping offset.
case <-sl.ctx.Done():
close(sl.stopped)
return
}
var last time.Time
alignedScrapeTime := time.Now().Round(0)
ticker := time.NewTicker(sl.interval)
defer ticker.Stop()
mainLoop:
for {
select {
case <-sl.parentCtx.Done():
close(sl.stopped)
return
case <-sl.ctx.Done():
break mainLoop
default:
}
// Temporary workaround for a jitter in go timers that causes disk space
// increase in TSDB.
// See https://github.com/prometheus/prometheus/issues/7846
// Calling Round ensures the time used is the wall clock, as otherwise .Sub
// and .Add on time.Time behave differently (see time package docs).
scrapeTime := time.Now().Round(0)
if AlignScrapeTimestamps && sl.interval > 100*ScrapeTimestampTolerance {
// For some reason, a tick might have been skipped, in which case we
// would call alignedScrapeTime.Add(interval) multiple times.
for scrapeTime.Sub(alignedScrapeTime) >= sl.interval {
alignedScrapeTime = alignedScrapeTime.Add(sl.interval)
}
// Align the scrape time if we are in the tolerance boundaries.
if scrapeTime.Sub(alignedScrapeTime) <= ScrapeTimestampTolerance {
scrapeTime = alignedScrapeTime
}
}
last = sl.scrapeAndReport(last, scrapeTime, errc)
select {
case <-sl.parentCtx.Done():
close(sl.stopped)
return
case <-sl.ctx.Done():
break mainLoop
case <-ticker.C:
}
}
close(sl.stopped)
if !sl.disabledEndOfRunStalenessMarkers {
sl.endOfRunStaleness(last, ticker, sl.interval)
}
}
// scrapeAndReport performs a scrape and then appends the result to the storage
// together with reporting metrics, by using as few appenders as possible.
// In the happy scenario, a single appender is used.
// This function uses sl.appenderCtx instead of sl.ctx on purpose. A scrape should
// only be cancelled on shutdown, not on reloads.
func (sl *scrapeLoop) scrapeAndReport(last, appendTime time.Time, errc chan<- error) time.Time {
start := time.Now()
// Only record after the first scrape.
if !last.IsZero() {
targetIntervalLength.WithLabelValues(sl.interval.String()).Observe(
time.Since(last).Seconds(),
)
}
b := sl.buffers.Get(sl.lastScrapeSize).([]byte)
defer sl.buffers.Put(b)
buf := bytes.NewBuffer(b)
var total, added, seriesAdded, bytes int
var err, appErr, scrapeErr error
app := sl.appender(sl.appenderCtx)
defer func() {
if err != nil {
app.Rollback()
return
}
err = app.Commit()
if err != nil {
level.Error(sl.l).Log("msg", "Scrape commit failed", "err", err)
}
}()
defer func() {
if err = sl.report(app, appendTime, time.Since(start), total, added, seriesAdded, bytes, scrapeErr); err != nil {
level.Warn(sl.l).Log("msg", "Appending scrape report failed", "err", err)
}
}()
if forcedErr := sl.getForcedError(); forcedErr != nil {
scrapeErr = forcedErr
// Add stale markers.
if _, _, _, err := sl.append(app, []byte{}, "", appendTime); err != nil {
app.Rollback()
app = sl.appender(sl.appenderCtx)
level.Warn(sl.l).Log("msg", "Append failed", "err", err)
}
if errc != nil {
errc <- forcedErr
}
return start
}
var contentType string
scrapeCtx, cancel := context.WithTimeout(sl.parentCtx, sl.timeout)
contentType, scrapeErr = sl.scraper.scrape(scrapeCtx, buf)
cancel()
if scrapeErr == nil {
b = buf.Bytes()
// NOTE: There were issues with misbehaving clients in the past
// that occasionally returned empty results. We don't want those
// to falsely reset our buffer size.
if len(b) > 0 {
sl.lastScrapeSize = len(b)
}
bytes = len(b)
} else {
level.Debug(sl.l).Log("msg", "Scrape failed", "err", scrapeErr)
if errc != nil {
errc <- scrapeErr
}
if errors.Is(scrapeErr, errBodySizeLimit) {
bytes = -1
}
}
// A failed scrape is the same as an empty scrape,
// we still call sl.append to trigger stale markers.
total, added, seriesAdded, appErr = sl.append(app, b, contentType, appendTime)
if appErr != nil {
app.Rollback()
app = sl.appender(sl.appenderCtx)
level.Debug(sl.l).Log("msg", "Append failed", "err", appErr)
// The append failed, probably due to a parse error or sample limit.
// Call sl.append again with an empty scrape to trigger stale markers.
if _, _, _, err := sl.append(app, []byte{}, "", appendTime); err != nil {
app.Rollback()
app = sl.appender(sl.appenderCtx)
level.Warn(sl.l).Log("msg", "Append failed", "err", err)
}
}
if scrapeErr == nil {
scrapeErr = appErr
}
return start
}
func (sl *scrapeLoop) setForcedError(err error) {
sl.forcedErrMtx.Lock()
defer sl.forcedErrMtx.Unlock()
sl.forcedErr = err
}
func (sl *scrapeLoop) getForcedError() error {
sl.forcedErrMtx.Lock()
defer sl.forcedErrMtx.Unlock()
return sl.forcedErr
}
func (sl *scrapeLoop) endOfRunStaleness(last time.Time, ticker *time.Ticker, interval time.Duration) {
// Scraping has stopped. We want to write stale markers but
// the target may be recreated, so we wait just over 2 scrape intervals
// before creating them.
// If the context is canceled, we presume the server is shutting down
// and will restart where is was. We do not attempt to write stale markers
// in this case.
if last.IsZero() {
// There never was a scrape, so there will be no stale markers.
return
}
// Wait for when the next scrape would have been, record its timestamp.
var staleTime time.Time
select {
case <-sl.parentCtx.Done():
return
case <-ticker.C:
staleTime = time.Now()
}
// Wait for when the next scrape would have been, if the target was recreated
// samples should have been ingested by now.
select {
case <-sl.parentCtx.Done():
return
case <-ticker.C:
}
// Wait for an extra 10% of the interval, just to be safe.
select {
case <-sl.parentCtx.Done():
return
case <-time.After(interval / 10):
}
// Call sl.append again with an empty scrape to trigger stale markers.
// If the target has since been recreated and scraped, the
// stale markers will be out of order and ignored.
// sl.context would have been cancelled, hence using sl.appenderCtx.
app := sl.appender(sl.appenderCtx)
var err error
defer func() {
if err != nil {
app.Rollback()
return
}
err = app.Commit()
if err != nil {
level.Warn(sl.l).Log("msg", "Stale commit failed", "err", err)
}
}()
if _, _, _, err = sl.append(app, []byte{}, "", staleTime); err != nil {
app.Rollback()
app = sl.appender(sl.appenderCtx)
level.Warn(sl.l).Log("msg", "Stale append failed", "err", err)
}
if err = sl.reportStale(app, staleTime); err != nil {
level.Warn(sl.l).Log("msg", "Stale report failed", "err", err)
}
}
// Stop the scraping. May still write data and stale markers after it has
// returned. Cancel the context to stop all writes.
func (sl *scrapeLoop) stop() {
sl.cancel()
<-sl.stopped
}
func (sl *scrapeLoop) disableEndOfRunStalenessMarkers() {
sl.disabledEndOfRunStalenessMarkers = true
}
func (sl *scrapeLoop) getCache() *scrapeCache {
return sl.cache
}
type appendErrors struct {
numOutOfOrder int
numDuplicates int
numOutOfBounds int
numExemplarOutOfOrder int
}
func (sl *scrapeLoop) append(app storage.Appender, b []byte, contentType string, ts time.Time) (total, added, seriesAdded int, err error) {
p, err := textparse.New(b, contentType, sl.scrapeClassicHistograms)
if err != nil {
level.Debug(sl.l).Log(
"msg", "Invalid content type on scrape, using prometheus parser as fallback.",
"content_type", contentType,
"err", err,
)
}
var (
defTime = timestamp.FromTime(ts)
appErrs = appendErrors{}
sampleLimitErr error
bucketLimitErr error
e exemplar.Exemplar // escapes to heap so hoisted out of loop
meta metadata.Metadata
metadataChanged bool
)
// updateMetadata updates the current iteration's metadata object and the
// metadataChanged value if we have metadata in the scrape cache AND the
// labelset is for a new series or the metadata for this series has just
// changed. It returns a boolean based on whether the metadata was updated.
updateMetadata := func(lset labels.Labels, isNewSeries bool) bool {
if !sl.appendMetadataToWAL {
return false
}
sl.cache.metaMtx.Lock()
defer sl.cache.metaMtx.Unlock()
metaEntry, metaOk := sl.cache.metadata[lset.Get(labels.MetricName)]
if metaOk && (isNewSeries || metaEntry.lastIterChange == sl.cache.iter) {
metadataChanged = true
meta.Type = metaEntry.Type
meta.Unit = metaEntry.Unit
meta.Help = metaEntry.Help
return true
}
return false
}
// Take an appender with limits.
app = appender(app, sl.sampleLimit, sl.bucketLimit)
defer func() {
if err != nil {
return
}
// Only perform cache cleaning if the scrape was not empty.
// An empty scrape (usually) is used to indicate a failed scrape.
sl.cache.iterDone(len(b) > 0)
}()
loop:
for {
var (
et textparse.Entry
sampleAdded, isHistogram bool
met []byte
parsedTimestamp *int64
val float64
h *histogram.Histogram
fh *histogram.FloatHistogram
)
if et, err = p.Next(); err != nil {
if errors.Is(err, io.EOF) {
err = nil
}
break
}
switch et {
case textparse.EntryType:
sl.cache.setType(p.Type())
continue
case textparse.EntryHelp:
sl.cache.setHelp(p.Help())
continue
case textparse.EntryUnit:
sl.cache.setUnit(p.Unit())
continue
case textparse.EntryComment:
continue
case textparse.EntryHistogram:
isHistogram = true
default:
}
total++
t := defTime
if isHistogram {
met, parsedTimestamp, h, fh = p.Histogram()
} else {
met, parsedTimestamp, val = p.Series()
}
if !sl.honorTimestamps {
parsedTimestamp = nil
}
if parsedTimestamp != nil {
t = *parsedTimestamp
}
// Zero metadata out for current iteration until it's resolved.
meta = metadata.Metadata{}
metadataChanged = false
if sl.cache.getDropped(met) {
continue
}
ce, ok := sl.cache.get(met)
var (
ref storage.SeriesRef
lset labels.Labels
hash uint64
)
if ok {
ref = ce.ref
lset = ce.lset
// Update metadata only if it changed in the current iteration.
updateMetadata(lset, false)
} else {
p.Metric(&lset)
hash = lset.Hash()
// Hash label set as it is seen local to the target. Then add target labels
// and relabeling and store the final label set.
lset = sl.sampleMutator(lset)
// The label set may be set to empty to indicate dropping.
if lset.IsEmpty() {
sl.cache.addDropped(met)
continue
}
if !lset.Has(labels.MetricName) {
err = errNameLabelMandatory
break loop
}
if !lset.IsValid() {
err = fmt.Errorf("invalid metric name or label names: %s", lset.String())
break loop
}
// If any label limits is exceeded the scrape should fail.
if err = verifyLabelLimits(lset, sl.labelLimits); err != nil {
targetScrapePoolExceededLabelLimits.Inc()
break loop
}
// Append metadata for new series if they were present.
updateMetadata(lset, true)
}
if isHistogram {
if h != nil {
ref, err = app.AppendHistogram(ref, lset, t, h, nil)
} else {
ref, err = app.AppendHistogram(ref, lset, t, nil, fh)
}
} else {
ref, err = app.Append(ref, lset, t, val)
}
sampleAdded, err = sl.checkAddError(ce, met, parsedTimestamp, err, &sampleLimitErr, &bucketLimitErr, &appErrs)
if err != nil {
if err != storage.ErrNotFound {
level.Debug(sl.l).Log("msg", "Unexpected error", "series", string(met), "err", err)
}
break loop
}
if !ok {
if parsedTimestamp == nil {
// Bypass staleness logic if there is an explicit timestamp.
sl.cache.trackStaleness(hash, lset)
}
sl.cache.addRef(met, ref, lset, hash)
if sampleAdded && sampleLimitErr == nil && bucketLimitErr == nil {
seriesAdded++
}
}
// Increment added even if there's an error so we correctly report the
// number of samples remaining after relabeling.
added++
for hasExemplar := p.Exemplar(&e); hasExemplar; hasExemplar = p.Exemplar(&e) {
if !e.HasTs {
e.Ts = t
}
_, exemplarErr := app.AppendExemplar(ref, lset, e)
exemplarErr = sl.checkAddExemplarError(exemplarErr, e, &appErrs)
if exemplarErr != nil {
// Since exemplar storage is still experimental, we don't fail the scrape on ingestion errors.
level.Debug(sl.l).Log("msg", "Error while adding exemplar in AddExemplar", "exemplar", fmt.Sprintf("%+v", e), "err", exemplarErr)
}
e = exemplar.Exemplar{} // reset for next time round loop
}
if sl.appendMetadataToWAL && metadataChanged {
if _, merr := app.UpdateMetadata(ref, lset, meta); merr != nil {
// No need to fail the scrape on errors appending metadata.
level.Debug(sl.l).Log("msg", "Error when appending metadata in scrape loop", "ref", fmt.Sprintf("%d", ref), "metadata", fmt.Sprintf("%+v", meta), "err", merr)
}
}
}
if sampleLimitErr != nil {
if err == nil {
err = sampleLimitErr
}
// We only want to increment this once per scrape, so this is Inc'd outside the loop.
targetScrapeSampleLimit.Inc()
}
if bucketLimitErr != nil {
if err == nil {
err = bucketLimitErr // If sample limit is hit, that error takes precedence.
}
// We only want to increment this once per scrape, so this is Inc'd outside the loop.
targetScrapeNativeHistogramBucketLimit.Inc()
}
if appErrs.numOutOfOrder > 0 {
level.Warn(sl.l).Log("msg", "Error on ingesting out-of-order samples", "num_dropped", appErrs.numOutOfOrder)
}
if appErrs.numDuplicates > 0 {
level.Warn(sl.l).Log("msg", "Error on ingesting samples with different value but same timestamp", "num_dropped", appErrs.numDuplicates)
}
if appErrs.numOutOfBounds > 0 {
level.Warn(sl.l).Log("msg", "Error on ingesting samples that are too old or are too far into the future", "num_dropped", appErrs.numOutOfBounds)
}
if appErrs.numExemplarOutOfOrder > 0 {
level.Warn(sl.l).Log("msg", "Error on ingesting out-of-order exemplars", "num_dropped", appErrs.numExemplarOutOfOrder)
}
if err == nil {
sl.cache.forEachStale(func(lset labels.Labels) bool {
// Series no longer exposed, mark it stale.
_, err = app.Append(0, lset, defTime, math.Float64frombits(value.StaleNaN))
switch errors.Cause(err) {
case storage.ErrOutOfOrderSample, storage.ErrDuplicateSampleForTimestamp:
// Do not count these in logging, as this is expected if a target
// goes away and comes back again with a new scrape loop.
err = nil
}
return err == nil
})
}
return
}
// Adds samples to the appender, checking the error, and then returns the # of samples added,
// whether the caller should continue to process more samples, and any sample or bucket limit errors.
func (sl *scrapeLoop) checkAddError(ce *cacheEntry, met []byte, tp *int64, err error, sampleLimitErr, bucketLimitErr *error, appErrs *appendErrors) (bool, error) {
switch errors.Cause(err) {
case nil:
if tp == nil && ce != nil {
sl.cache.trackStaleness(ce.hash, ce.lset)
}
return true, nil
case storage.ErrNotFound:
return false, storage.ErrNotFound
case storage.ErrOutOfOrderSample:
appErrs.numOutOfOrder++
level.Debug(sl.l).Log("msg", "Out of order sample", "series", string(met))
targetScrapeSampleOutOfOrder.Inc()
return false, nil
case storage.ErrDuplicateSampleForTimestamp:
appErrs.numDuplicates++
level.Debug(sl.l).Log("msg", "Duplicate sample for timestamp", "series", string(met))
targetScrapeSampleDuplicate.Inc()
return false, nil
case storage.ErrOutOfBounds:
appErrs.numOutOfBounds++
level.Debug(sl.l).Log("msg", "Out of bounds metric", "series", string(met))
targetScrapeSampleOutOfBounds.Inc()
return false, nil
case errSampleLimit:
// Keep on parsing output if we hit the limit, so we report the correct
// total number of samples scraped.
*sampleLimitErr = err
return false, nil
case errBucketLimit:
// Keep on parsing output if we hit the limit, so we report the correct
// total number of samples scraped.
*bucketLimitErr = err
return false, nil
default:
return false, err
}
}
func (sl *scrapeLoop) checkAddExemplarError(err error, e exemplar.Exemplar, appErrs *appendErrors) error {
switch errors.Cause(err) {
case storage.ErrNotFound:
return storage.ErrNotFound
case storage.ErrOutOfOrderExemplar:
appErrs.numExemplarOutOfOrder++
level.Debug(sl.l).Log("msg", "Out of order exemplar", "exemplar", fmt.Sprintf("%+v", e))
targetScrapeExemplarOutOfOrder.Inc()
return nil
default:
return err
}
}
// The constants are suffixed with the invalid \xff unicode rune to avoid collisions
// with scraped metrics in the cache.
var (
scrapeHealthMetricName = []byte("up" + "\xff")
scrapeDurationMetricName = []byte("scrape_duration_seconds" + "\xff")
scrapeSamplesMetricName = []byte("scrape_samples_scraped" + "\xff")
samplesPostRelabelMetricName = []byte("scrape_samples_post_metric_relabeling" + "\xff")
scrapeSeriesAddedMetricName = []byte("scrape_series_added" + "\xff")
scrapeTimeoutMetricName = []byte("scrape_timeout_seconds" + "\xff")
scrapeSampleLimitMetricName = []byte("scrape_sample_limit" + "\xff")
scrapeBodySizeBytesMetricName = []byte("scrape_body_size_bytes" + "\xff")
)
func (sl *scrapeLoop) report(app storage.Appender, start time.Time, duration time.Duration, scraped, added, seriesAdded, bytes int, scrapeErr error) (err error) {
sl.scraper.Report(start, duration, scrapeErr)
ts := timestamp.FromTime(start)
var health float64
if scrapeErr == nil {
health = 1
}
if err = sl.addReportSample(app, scrapeHealthMetricName, ts, health); err != nil {
return
}
if err = sl.addReportSample(app, scrapeDurationMetricName, ts, duration.Seconds()); err != nil {
return
}
if err = sl.addReportSample(app, scrapeSamplesMetricName, ts, float64(scraped)); err != nil {
return
}
if err = sl.addReportSample(app, samplesPostRelabelMetricName, ts, float64(added)); err != nil {
return
}
if err = sl.addReportSample(app, scrapeSeriesAddedMetricName, ts, float64(seriesAdded)); err != nil {
return
}
if sl.reportExtraMetrics {
if err = sl.addReportSample(app, scrapeTimeoutMetricName, ts, sl.timeout.Seconds()); err != nil {
return
}
if err = sl.addReportSample(app, scrapeSampleLimitMetricName, ts, float64(sl.sampleLimit)); err != nil {
return
}
if err = sl.addReportSample(app, scrapeBodySizeBytesMetricName, ts, float64(bytes)); err != nil {
return
}
}
return
}
func (sl *scrapeLoop) reportStale(app storage.Appender, start time.Time) (err error) {
ts := timestamp.FromTime(start)
stale := math.Float64frombits(value.StaleNaN)
if err = sl.addReportSample(app, scrapeHealthMetricName, ts, stale); err != nil {
return
}
if err = sl.addReportSample(app, scrapeDurationMetricName, ts, stale); err != nil {
return
}
if err = sl.addReportSample(app, scrapeSamplesMetricName, ts, stale); err != nil {
return
}
if err = sl.addReportSample(app, samplesPostRelabelMetricName, ts, stale); err != nil {
return
}
if err = sl.addReportSample(app, scrapeSeriesAddedMetricName, ts, stale); err != nil {
return
}
if sl.reportExtraMetrics {
if err = sl.addReportSample(app, scrapeTimeoutMetricName, ts, stale); err != nil {
return
}
if err = sl.addReportSample(app, scrapeSampleLimitMetricName, ts, stale); err != nil {
return
}
if err = sl.addReportSample(app, scrapeBodySizeBytesMetricName, ts, stale); err != nil {
return
}
}
return
}
func (sl *scrapeLoop) addReportSample(app storage.Appender, s []byte, t int64, v float64) error {
ce, ok := sl.cache.get(s)
var ref storage.SeriesRef
var lset labels.Labels
if ok {
ref = ce.ref
lset = ce.lset
} else {
// The constants are suffixed with the invalid \xff unicode rune to avoid collisions
// with scraped metrics in the cache.
// We have to drop it when building the actual metric.
lset = labels.FromStrings(labels.MetricName, string(s[:len(s)-1]))
lset = sl.reportSampleMutator(lset)
}
ref, err := app.Append(ref, lset, t, v)
switch errors.Cause(err) {
case nil:
if !ok {
sl.cache.addRef(s, ref, lset, lset.Hash())
}
return nil
case storage.ErrOutOfOrderSample, storage.ErrDuplicateSampleForTimestamp:
// Do not log here, as this is expected if a target goes away and comes back
// again with a new scrape loop.
return nil
default:
return err
}
}
// zeroConfig returns a new scrape config that only contains configuration items
// that alter metrics.
func zeroConfig(c *config.ScrapeConfig) *config.ScrapeConfig {
z := *c
// We zero out the fields that for sure don't affect scrape.
z.ScrapeInterval = 0
z.ScrapeTimeout = 0
z.SampleLimit = 0
z.HTTPClientConfig = config_util.HTTPClientConfig{}
return &z
}
// reusableCache compares two scrape config and tells whether the cache is still
// valid.
func reusableCache(r, l *config.ScrapeConfig) bool {
if r == nil || l == nil {
return false
}
return reflect.DeepEqual(zeroConfig(r), zeroConfig(l))
}
// CtxKey is a dedicated type for keys of context-embedded values propagated
// with the scrape context.
type ctxKey int
// Valid CtxKey values.
const (
ctxKeyMetadata ctxKey = iota + 1
ctxKeyTarget
)
func ContextWithMetricMetadataStore(ctx context.Context, s MetricMetadataStore) context.Context {
return context.WithValue(ctx, ctxKeyMetadata, s)
}
func MetricMetadataStoreFromContext(ctx context.Context) (MetricMetadataStore, bool) {
s, ok := ctx.Value(ctxKeyMetadata).(MetricMetadataStore)
return s, ok
}
func ContextWithTarget(ctx context.Context, t *Target) context.Context {
return context.WithValue(ctx, ctxKeyTarget, t)
}
func TargetFromContext(ctx context.Context) (*Target, bool) {
t, ok := ctx.Value(ctxKeyTarget).(*Target)
return t, ok
}