*: use latest release of staticcheck (#5057)

* *: use latest release of staticcheck

It also fixes a couple of things in the code flagged by the additional
checks.

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

* Use official release of staticcheck

Also run 'go list' before staticcheck to avoid failures when downloading packages.

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

Makefile

@@ -14,13 +14,8 @@
 include Makefile.common
 
 STATICCHECK_IGNORE = \
-  github.com/prometheus/prometheus/discovery/kubernetes/kubernetes.go:SA1019 \
-  github.com/prometheus/prometheus/discovery/kubernetes/node.go:SA1019 \
-  github.com/prometheus/prometheus/documentation/examples/remote_storage/remote_storage_adapter/main.go:SA1019 \
   github.com/prometheus/prometheus/pkg/textparse/promlex.l.go:SA4006 \
   github.com/prometheus/prometheus/pkg/textparse/openmetricslex.l.go:SA4006 \
-  github.com/prometheus/prometheus/pkg/pool/pool.go:SA6002 \
-  github.com/prometheus/prometheus/promql/engine.go:SA6002 \
   github.com/prometheus/prometheus/prompb/rpc.pb.gw.go:SA1019
 
 DOCKER_IMAGE_NAME       ?= prometheus

Makefile.common

@@ -73,6 +73,8 @@ endif
 
 PROMU_VERSION ?= 0.2.0
 PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_VERSION)/promu-$(PROMU_VERSION).$(GO_BUILD_PLATFORM).tar.gz
+STATICCHECK_VERSION ?= 2019.1
+STATICCHECK_URL     := https://github.com/dominikh/go-tools/releases/download/$(STATICCHECK_VERSION)/staticcheck_$(GOHOSTOS)_$(GOHOSTARCH)
 
 PREFIX                  ?= $(shell pwd)
 BIN_DIR                 ?= $(shell pwd)
@@ -138,8 +140,12 @@ common-vet:
 .PHONY: common-staticcheck
 common-staticcheck: $(STATICCHECK)
 	@echo ">> running staticcheck"
+	chmod +x $(STATICCHECK)
 ifdef GO111MODULE
-	GO111MODULE=$(GO111MODULE) $(STATICCHECK) -ignore "$(STATICCHECK_IGNORE)" -checks "SA*" $(pkgs)
+# 'go list' needs to be executed before staticcheck to prepopulate the modules cache.
+# Otherwise staticcheck might fail randomly for some reason not yet explained.
+	GO111MODULE=$(GO111MODULE) $(GO) list -e -compiled -test=true -export=false -deps=true -find=false -tags= -- ./... > /dev/null
+	GO111MODULE=$(GO111MODULE) $(STATICCHECK) -ignore "$(STATICCHECK_IGNORE)" $(pkgs)
 else
 	$(STATICCHECK) -ignore "$(STATICCHECK_IGNORE)" $(pkgs)
 endif
@@ -200,21 +206,9 @@ proto:
 	@echo ">> generating code from proto files"
 	@./scripts/genproto.sh
 
-.PHONY: $(STATICCHECK)
 $(STATICCHECK):
-ifdef GO111MODULE
+	mkdir -p $(FIRST_GOPATH)/bin
-# Get staticcheck from a temporary directory to avoid modifying the local go.{mod,sum}.
+	curl -s -L $(STATICCHECK_URL) > $(STATICCHECK)
-# See https://github.com/golang/go/issues/27643.
-# For now, we are using the next branch of staticcheck because master isn't compatible yet with Go modules.
-	tmpModule=$$(mktemp -d 2>&1) && \
-	mkdir -p $${tmpModule}/staticcheck && \
-	cd "$${tmpModule}"/staticcheck && \
-	GO111MODULE=on $(GO) mod init example.com/staticcheck && \
-	GO111MODULE=on GOOS= GOARCH= $(GO) get -u honnef.co/go/tools/cmd/staticcheck@next && \
-	rm -rf $${tmpModule};
-else
-	GOOS= GOARCH= GO111MODULE=off $(GO) get -u honnef.co/go/tools/cmd/staticcheck
-endif
 
 ifdef GOVENDOR
 .PHONY: $(GOVENDOR)

cmd/promtool/archive.go

@@ -22,12 +22,6 @@ import (
 
 const filePerm = 0644
 
-type archiver interface {
-	write(filename string, b []byte) error
-	close() error
-	filename() string
-}
-
 type tarGzFileWriter struct {
 	tarWriter *tar.Writer
 	gzWriter  *gzip.Writer
@@ -72,7 +66,3 @@ func (w *tarGzFileWriter) write(filename string, b []byte) error {
 	}
 	return nil
 }
-
-func (w *tarGzFileWriter) filename() string {
-	return w.file.Name()
-}

cmd/promtool/http.go

@@ -24,11 +24,6 @@ import (
 
 const defaultTimeout = 2 * time.Minute
 
-type httpClient interface {
-	do(req *http.Request) (*http.Response, []byte, error)
-	urlJoin(path string) string
-}
-
 type prometheusHTTPClient struct {
 	requestTimeout time.Duration
 	httpClient     api.Client

cmd/promtool/unittest.go

@@ -84,7 +84,7 @@ func ruleUnitTest(filename string) []error {
 	groupOrderMap := make(map[string]int)
 	for i, gn := range unitTestInp.GroupEvalOrder {
 		if _, ok := groupOrderMap[gn]; ok {
-			return []error{fmt.Errorf("Group name repeated in evaluation order: %s", gn)}
+			return []error{fmt.Errorf("group name repeated in evaluation order: %s", gn)}
 		}
 		groupOrderMap[gn] = i
 	}

config/config_test.go

@@ -756,23 +756,23 @@ var expectedErrors = []struct {
 	},
 	{
 		filename: "azure_client_id_missing.bad.yml",
-		errMsg:   "Azure SD configuration requires a client_id",
+		errMsg:   "azure SD configuration requires a client_id",
 	},
 	{
 		filename: "azure_client_secret_missing.bad.yml",
-		errMsg:   "Azure SD configuration requires a client_secret",
+		errMsg:   "azure SD configuration requires a client_secret",
 	},
 	{
 		filename: "azure_subscription_id_missing.bad.yml",
-		errMsg:   "Azure SD configuration requires a subscription_id",
+		errMsg:   "azure SD configuration requires a subscription_id",
 	},
 	{
 		filename: "azure_tenant_id_missing.bad.yml",
-		errMsg:   "Azure SD configuration requires a tenant_id",
+		errMsg:   "azure SD configuration requires a tenant_id",
 	},
 	{
 		filename: "azure_authentication_method.bad.yml",
-		errMsg:   "Unknown authentication_type \"invalid\". Supported types are \"OAuth\" or \"ManagedIdentity\"",
+		errMsg:   "unknown authentication_type \"invalid\". Supported types are \"OAuth\" or \"ManagedIdentity\"",
 	},
 	{
 		filename: "empty_scrape_config.bad.yml",

discovery/azure/azure.go

@@ -85,7 +85,7 @@ type SDConfig struct {
 
 func validateAuthParam(param, name string) error {
 	if len(param) == 0 {
-		return fmt.Errorf("Azure SD configuration requires a %s", name)
+		return fmt.Errorf("azure SD configuration requires a %s", name)
 	}
 	return nil
 }
@@ -116,7 +116,7 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	}
 
 	if c.AuthenticationMethod != authMethodOAuth && c.AuthenticationMethod != authMethodManagedIdentity {
-		return fmt.Errorf("Unknown authentication_type %q. Supported types are %q or %q", c.AuthenticationMethod, authMethodOAuth, authMethodManagedIdentity)
+		return fmt.Errorf("unknown authentication_type %q. Supported types are %q or %q", c.AuthenticationMethod, authMethodOAuth, authMethodManagedIdentity)
 	}
 
 	return nil

discovery/consul/consul.go

@@ -131,7 +131,7 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		return err
 	}
 	if strings.TrimSpace(c.Server) == "" {
-		return fmt.Errorf("Consul SD configuration requires a server address")
+		return fmt.Errorf("consul SD configuration requires a server address")
 	}
 	return nil
 }
@@ -267,7 +267,7 @@ func (d *Discovery) getDatacenter() error {
 
 	dc, ok := info["Config"]["Datacenter"].(string)
 	if !ok {
-		err := fmt.Errorf("Invalid value '%v' for Config.Datacenter", info["Config"]["Datacenter"])
+		err := fmt.Errorf("invalid value '%v' for Config.Datacenter", info["Config"]["Datacenter"])
 		level.Error(d.logger).Log("msg", "Error retrieving datacenter name", "err", err)
 		return err
 	}

discovery/kubernetes/endpoints.go

@@ -178,7 +178,7 @@ func convertToEndpoints(o interface{}) (*apiv1.Endpoints, error) {
 		return endpoints, nil
 	}
 
-	return nil, fmt.Errorf("Received unexpected object: %v", o)
+	return nil, fmt.Errorf("received unexpected object: %v", o)
 }
 
 func endpointsSource(ep *apiv1.Endpoints) string {

discovery/kubernetes/ingress.go

@@ -118,7 +118,7 @@ func convertToIngress(o interface{}) (*v1beta1.Ingress, error) {
 		return ingress, nil
 	}
 
-	return nil, fmt.Errorf("Received unexpected object: %v", o)
+	return nil, fmt.Errorf("received unexpected object: %v", o)
 }
 
 func ingressSource(s *v1beta1.Ingress) string {

discovery/kubernetes/kubernetes.go

@@ -80,7 +80,7 @@ func (c *Role) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	case RoleNode, RolePod, RoleService, RoleEndpoint, RoleIngress:
 		return nil
 	default:
-		return fmt.Errorf("Unknown Kubernetes SD role %q", *c)
+		return fmt.Errorf("unknown Kubernetes SD role %q", *c)
 	}
 }
 

discovery/kubernetes/node.go

@@ -127,7 +127,7 @@ func convertToNode(o interface{}) (*apiv1.Node, error) {
 		return node, nil
 	}
 
-	return nil, fmt.Errorf("Received unexpected object: %v", o)
+	return nil, fmt.Errorf("received unexpected object: %v", o)
 }
 
 func nodeSource(n *apiv1.Node) string {

discovery/kubernetes/pod.go

@@ -131,7 +131,7 @@ func convertToPod(o interface{}) (*apiv1.Pod, error) {
 		return pod, nil
 	}
 
-	return nil, fmt.Errorf("Received unexpected object: %v", o)
+	return nil, fmt.Errorf("received unexpected object: %v", o)
 }
 
 const (

discovery/kubernetes/service.go

@@ -123,7 +123,7 @@ func convertToService(o interface{}) (*apiv1.Service, error) {
 	if ok {
 		return service, nil
 	}
-	return nil, fmt.Errorf("Received unexpected object: %v", o)
+	return nil, fmt.Errorf("received unexpected object: %v", o)
 }
 
 func serviceSource(s *apiv1.Service) string {

discovery/marathon/marathon.go

@@ -356,7 +356,7 @@ func fetchApps(client *http.Client, url string) (*AppList, error) {
 	defer resp.Body.Close()
 
 	if (resp.StatusCode < 200) || (resp.StatusCode >= 300) {
-		return nil, fmt.Errorf("Non 2xx status '%v' response during marathon service discovery", resp.StatusCode)
+		return nil, fmt.Errorf("non 2xx status '%v' response during marathon service discovery", resp.StatusCode)
 	}
 
 	var apps AppList

discovery/openstack/openstack.go

@@ -104,7 +104,7 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		return fmt.Errorf("role missing (one of: instance, hypervisor)")
 	}
 	if c.Region == "" {
-		return fmt.Errorf("Openstack SD configuration requires a region")
+		return fmt.Errorf("openstack SD configuration requires a region")
 	}
 	return nil
 }

discovery/triton/triton.go

@@ -41,7 +41,6 @@ const (
 	tritonLabelMachineBrand = tritonLabel + "machine_brand"
 	tritonLabelMachineImage = tritonLabel + "machine_image"
 	tritonLabelServerID     = tritonLabel + "server_id"
-	namespace               = "prometheus"
 )
 
 var (
@@ -84,16 +83,16 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		return err
 	}
 	if c.Account == "" {
-		return fmt.Errorf("Triton SD configuration requires an account")
+		return fmt.Errorf("triton SD configuration requires an account")
 	}
 	if c.DNSSuffix == "" {
-		return fmt.Errorf("Triton SD configuration requires a dns_suffix")
+		return fmt.Errorf("triton SD configuration requires a dns_suffix")
 	}
 	if c.Endpoint == "" {
-		return fmt.Errorf("Triton SD configuration requires an endpoint")
+		return fmt.Errorf("triton SD configuration requires an endpoint")
 	}
 	if c.RefreshInterval <= 0 {
-		return fmt.Errorf("Triton SD configuration requires RefreshInterval to be a positive integer")
+		return fmt.Errorf("triton SD configuration requires RefreshInterval to be a positive integer")
 	}
 	return nil
 }

documentation/examples/custom-sd/adapter-usage/main.go

@@ -43,18 +43,12 @@ var (
 	addressLabel = model.MetaLabelPrefix + "consul_address"
 	// nodeLabel is the name for the label containing a target's node name.
 	nodeLabel = model.MetaLabelPrefix + "consul_node"
-	// metaDataLabel is the prefix for the labels mapping to a target's metadata.
-	metaDataLabel = model.MetaLabelPrefix + "consul_metadata_"
 	// tagsLabel is the name of the label containing the tags assigned to the target.
 	tagsLabel = model.MetaLabelPrefix + "consul_tags"
-	// serviceLabel is the name of the label containing the service name.
-	serviceLabel = model.MetaLabelPrefix + "consul_service"
 	// serviceAddressLabel is the name of the label containing the (optional) service address.
 	serviceAddressLabel = model.MetaLabelPrefix + "consul_service_address"
 	//servicePortLabel is the name of the label containing the service port.
 	servicePortLabel = model.MetaLabelPrefix + "consul_service_port"
-	// datacenterLabel is the name of the label containing the datacenter ID.
-	datacenterLabel = model.MetaLabelPrefix + "consul_dc"
 	// serviceIDLabel is the name of the label containing the service ID.
 	serviceIDLabel = model.MetaLabelPrefix + "consul_service_id"
 )
@@ -89,12 +83,11 @@ type sdConfig struct {
 // Note: This is the struct with your implementation of the Discoverer interface (see Run function).
 // Discovery retrieves target information from a Consul server and updates them via watches.
 type discovery struct {
-	address          string
+	address         string
-	refreshInterval  int
+	refreshInterval int
-	clientDatacenter string
+	tagSeparator    string
-	tagSeparator     string
+	logger          log.Logger
-	logger           log.Logger
+	oldSourceList   map[string]bool
-	oldSourceList    map[string]bool
 }
 
 func (d *discovery) parseServiceNodes(resp *http.Response, name string) (*targetgroup.Group, error) {

promql/engine.go

@@ -175,7 +175,7 @@ func (q *query) Exec(ctx context.Context) *Result {
 		span.SetTag(queryTag, q.stmt.String())
 	}
 
-	res, err, warnings := q.ng.exec(ctx, q)
+	res, warnings, err := q.ng.exec(ctx, q)
 	return &Result{Err: err, Value: res, Warnings: warnings}
 }
 
@@ -353,7 +353,7 @@ func (ng *Engine) newTestQuery(f func(context.Context) error) Query {
 //
 // At this point per query only one EvalStmt is evaluated. Alert and record
 // statements are not handled by the Engine.
-func (ng *Engine) exec(ctx context.Context, q *query) (Value, error, storage.Warnings) {
+func (ng *Engine) exec(ctx context.Context, q *query) (Value, storage.Warnings, error) {
 	ng.metrics.currentQueries.Inc()
 	defer ng.metrics.currentQueries.Dec()
 
@@ -366,7 +366,7 @@ func (ng *Engine) exec(ctx context.Context, q *query) (Value, error, storage.War
 	queueSpanTimer, _ := q.stats.GetSpanTimer(ctx, stats.ExecQueueTime, ng.metrics.queryQueueTime)
 
 	if err := ng.gate.Start(ctx); err != nil {
-		return nil, contextErr(err, "query queue"), nil
+		return nil, nil, contextErr(err, "query queue")
 	}
 	defer ng.gate.Done()
 
@@ -382,14 +382,14 @@ func (ng *Engine) exec(ctx context.Context, q *query) (Value, error, storage.War
 
 	// The base context might already be canceled on the first iteration (e.g. during shutdown).
 	if err := contextDone(ctx, env); err != nil {
-		return nil, err, nil
+		return nil, nil, err
 	}
 
 	switch s := q.Statement().(type) {
 	case *EvalStmt:
 		return ng.execEvalStmt(ctx, q, s)
 	case testStmt:
-		return nil, s(ctx), nil
+		return nil, nil, s(ctx)
 	}
 
 	panic(fmt.Errorf("promql.Engine.exec: unhandled statement of type %T", q.Statement()))
@@ -404,9 +404,9 @@ func durationMilliseconds(d time.Duration) int64 {
 }
 
 // execEvalStmt evaluates the expression of an evaluation statement for the given time range.
-func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (Value, error, storage.Warnings) {
+func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (Value, storage.Warnings, error) {
 	prepareSpanTimer, ctxPrepare := query.stats.GetSpanTimer(ctx, stats.QueryPreparationTime, ng.metrics.queryPrepareTime)
-	querier, err, warnings := ng.populateSeries(ctxPrepare, query.queryable, s)
+	querier, warnings, err := ng.populateSeries(ctxPrepare, query.queryable, s)
 	prepareSpanTimer.Finish()
 
 	// XXX(fabxc): the querier returned by populateSeries might be instantiated
@@ -417,7 +417,7 @@ func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (
 	}
 
 	if err != nil {
-		return nil, err, warnings
+		return nil, warnings, err
 	}
 
 	evalSpanTimer, _ := query.stats.GetSpanTimer(ctx, stats.InnerEvalTime, ng.metrics.queryInnerEval)
@@ -435,7 +435,7 @@ func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (
 		}
 		val, err := evaluator.Eval(s.Expr)
 		if err != nil {
-			return nil, err, warnings
+			return nil, warnings, err
 		}
 
 		evalSpanTimer.Finish()
@@ -454,11 +454,11 @@ func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (
 				// timestamp as that is when we ran the evaluation.
 				vector[i] = Sample{Metric: s.Metric, Point: Point{V: s.Points[0].V, T: start}}
 			}
-			return vector, nil, warnings
+			return vector, warnings, nil
 		case ValueTypeScalar:
-			return Scalar{V: mat[0].Points[0].V, T: start}, nil, warnings
+			return Scalar{V: mat[0].Points[0].V, T: start}, warnings, nil
 		case ValueTypeMatrix:
-			return mat, nil, warnings
+			return mat, warnings, nil
 		default:
 			panic(fmt.Errorf("promql.Engine.exec: unexpected expression type %q", s.Expr.Type()))
 		}
@@ -477,7 +477,7 @@ func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (
 	}
 	val, err := evaluator.Eval(s.Expr)
 	if err != nil {
-		return nil, err, warnings
+		return nil, warnings, err
 	}
 	evalSpanTimer.Finish()
 
@@ -488,7 +488,7 @@ func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (
 	query.matrix = mat
 
 	if err := contextDone(ctx, "expression evaluation"); err != nil {
-		return nil, err, warnings
+		return nil, warnings, err
 	}
 
 	// TODO(fabxc): order ensured by storage?
@@ -497,7 +497,7 @@ func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (
 	sort.Sort(mat)
 	sortSpanTimer.Finish()
 
-	return mat, nil, warnings
+	return mat, warnings, nil
 }
 
 // cumulativeSubqueryOffset returns the sum of range and offset of all subqueries in the path.
@@ -512,7 +512,7 @@ func (ng *Engine) cumulativeSubqueryOffset(path []Node) time.Duration {
 	return subqOffset
 }
 
-func (ng *Engine) populateSeries(ctx context.Context, q storage.Queryable, s *EvalStmt) (storage.Querier, error, storage.Warnings) {
+func (ng *Engine) populateSeries(ctx context.Context, q storage.Queryable, s *EvalStmt) (storage.Querier, storage.Warnings, error) {
 	var maxOffset time.Duration
 	Inspect(s.Expr, func(node Node, path []Node) error {
 		subqOffset := ng.cumulativeSubqueryOffset(path)
@@ -539,7 +539,7 @@ func (ng *Engine) populateSeries(ctx context.Context, q storage.Queryable, s *Ev
 
 	querier, err := q.Querier(ctx, timestamp.FromTime(mint), timestamp.FromTime(s.End))
 	if err != nil {
-		return nil, err, nil
+		return nil, nil, err
 	}
 
 	var warnings storage.Warnings
@@ -592,7 +592,7 @@ func (ng *Engine) populateSeries(ctx context.Context, q storage.Queryable, s *Ev
 		}
 		return nil
 	})
-	return querier, err, warnings
+	return querier, warnings, err
 }
 
 // extractFuncFromPath walks up the path and searches for the first instance of
@@ -1243,6 +1243,7 @@ func getPointSlice(sz int) []Point {
 }
 
 func putPointSlice(p []Point) {
+	//lint:ignore SA6002 relax staticcheck verification.
 	pointPool.Put(p[:0])
 }
 
@@ -1665,21 +1666,6 @@ func vectorElemBinop(op ItemType, lhs, rhs float64) (float64, bool) {
 	panic(fmt.Errorf("operator %q not allowed for operations between Vectors", op))
 }
 
-// intersection returns the metric of common label/value pairs of two input metrics.
-func intersection(ls1, ls2 labels.Labels) labels.Labels {
-	res := make(labels.Labels, 0, 5)
-
-	for _, l1 := range ls1 {
-		for _, l2 := range ls2 {
-			if l1.Name == l2.Name && l1.Value == l2.Value {
-				res = append(res, l1)
-				continue
-			}
-		}
-	}
-	return res
-}
-
 type groupedAggregation struct {
 	labels      labels.Labels
 	value       float64

promql/printer.go

@@ -155,7 +155,7 @@ func (node *MatrixSelector) String() string {
 func (node *SubqueryExpr) String() string {
 	step := ""
 	if node.Step != 0 {
-		step = fmt.Sprintf("%s", model.Duration(node.Step))
+		step = model.Duration(node.Step).String()
 	}
 	return fmt.Sprintf("%s[%s:%s]", node.Expr.String(), model.Duration(node.Range), step)
 }

promql/value.go

@@ -311,10 +311,7 @@ func (ssi *storageSeriesIterator) At() (t int64, v float64) {
 
 func (ssi *storageSeriesIterator) Next() bool {
 	ssi.curr++
-	if ssi.curr >= len(ssi.points) {
+	return ssi.curr < len(ssi.points)
-		return false
-	}
-	return true
 }
 
 func (ssi *storageSeriesIterator) Err() error {

rules/alerting.go

@@ -206,10 +206,6 @@ func (r *AlertingRule) Annotations() labels.Labels {
 	return r.annotations
 }
 
-func (r *AlertingRule) equal(o *AlertingRule) bool {
-	return r.name == o.name && labels.Equal(r.labels, o.labels)
-}
-
 func (r *AlertingRule) sample(alert *Alert, ts time.Time) promql.Sample {
 	lb := labels.NewBuilder(r.labels)
 

scrape/scrape.go

@@ -927,6 +927,7 @@ type sample struct {
 	v      float64
 }
 
+//lint:ignore U1000 staticcheck falsely reports that samples is unused.
 type samples []sample
 
 func (s samples) Len() int      { return len(s) }

storage/remote/codec.go

@@ -302,13 +302,13 @@ func (c *concreteSeriesIterator) Err() error {
 func validateLabelsAndMetricName(ls labels.Labels) error {
 	for _, l := range ls {
 		if l.Name == labels.MetricName && !model.IsValidMetricName(model.LabelValue(l.Value)) {
-			return fmt.Errorf("Invalid metric name: %v", l.Value)
+			return fmt.Errorf("invalid metric name: %v", l.Value)
 		}
 		if !model.LabelName(l.Name).IsValid() {
-			return fmt.Errorf("Invalid label name: %v", l.Name)
+			return fmt.Errorf("invalid label name: %v", l.Name)
 		}
 		if !model.LabelValue(l.Value).IsValid() {
-			return fmt.Errorf("Invalid label value: %v", l.Value)
+			return fmt.Errorf("invalid label value: %v", l.Value)
 		}
 	}
 	return nil

storage/remote/queue_manager.go

@@ -401,10 +401,6 @@ func (t *QueueManager) newShards(numShards int) *shards {
 	return s
 }
 
-func (s *shards) len() int {
-	return len(s.queues)
-}
-
 func (s *shards) start() {
 	for i := 0; i < len(s.queues); i++ {
 		go s.runShard(i)
@@ -426,7 +422,6 @@ func (s *shards) stop(deadline time.Duration) {
 	// Force an unclean shutdown.
 	s.cancel()
 	<-s.done
-	return
 }
 
 func (s *shards) enqueue(sample *model.Sample) bool {

storage/remote/queue_manager_test.go

@@ -323,7 +323,7 @@ func TestShutdown(t *testing.T) {
 
 	start := time.Now()
 	m.Stop()
-	duration := time.Now().Sub(start)
+	duration := time.Since(start)
 	if duration > deadline+(deadline/10) {
 		t.Errorf("Took too long to shutdown: %s > %s", duration, deadline)
 	}

util/httputil/compression_test.go

@@ -118,7 +118,7 @@ func TestCompressionHandler_Gzip(t *testing.T) {
 		t.Error("unexpected error while reading from response body")
 	}
 
-	actual := string(buf.Bytes())
+	actual := buf.String()
 	expected := "Hello World!"
 	if expected != actual {
 		t.Errorf("expected response with content %s, but got %s", expected, actual)
@@ -168,7 +168,7 @@ func TestCompressionHandler_Deflate(t *testing.T) {
 		t.Error("unexpected error while reading from response body")
 	}
 
-	actual := string(buf.Bytes())
+	actual := buf.String()
 	expected := "Hello World!"
 	if expected != actual {
 		t.Errorf("expected response with content %s, but got %s", expected, actual)

util/treecache/treecache.go

@@ -63,12 +63,11 @@ func (zl ZookeeperLogger) Printf(s string, i ...interface{}) {
 // A ZookeeperTreeCache keeps data from all children of a Zookeeper path
 // locally cached and updated according to received events.
 type ZookeeperTreeCache struct {
-	conn     *zk.Conn
+	conn   *zk.Conn
-	prefix   string
+	prefix string
-	events   chan ZookeeperTreeCacheEvent
+	events chan ZookeeperTreeCacheEvent
-	zkEvents chan zk.Event
+	stop   chan struct{}
-	stop     chan struct{}
+	head   *zookeeperTreeCacheNode
-	head     *zookeeperTreeCacheNode
 
 	logger log.Logger
 }

web/api/v1/api.go

@@ -923,7 +923,7 @@ func (api *API) remoteRead(w http.ResponseWriter, r *http.Request) {
 
 func (api *API) deleteSeries(r *http.Request) apiFuncResult {
 	if !api.enableAdmin {
-		return apiFuncResult{nil, &apiError{errorUnavailable, errors.New("Admin APIs disabled")}, nil, nil}
+		return apiFuncResult{nil, &apiError{errorUnavailable, errors.New("admin APIs disabled")}, nil, nil}
 	}
 	db := api.db()
 	if db == nil {
@@ -980,7 +980,7 @@ func (api *API) deleteSeries(r *http.Request) apiFuncResult {
 
 func (api *API) snapshot(r *http.Request) apiFuncResult {
 	if !api.enableAdmin {
-		return apiFuncResult{nil, &apiError{errorUnavailable, errors.New("Admin APIs disabled")}, nil, nil}
+		return apiFuncResult{nil, &apiError{errorUnavailable, errors.New("admin APIs disabled")}, nil, nil}
 	}
 	var (
 		skipHead bool
@@ -1019,7 +1019,7 @@ func (api *API) snapshot(r *http.Request) apiFuncResult {
 
 func (api *API) cleanTombstones(r *http.Request) apiFuncResult {
 	if !api.enableAdmin {
-		return apiFuncResult{nil, &apiError{errorUnavailable, errors.New("Admin APIs disabled")}, nil, nil}
+		return apiFuncResult{nil, &apiError{errorUnavailable, errors.New("admin APIs disabled")}, nil, nil}
 	}
 	db := api.db()
 	if db == nil {

web/api/v2/api.go

@@ -36,7 +36,6 @@ import (
 	"github.com/prometheus/tsdb"
 	tsdbLabels "github.com/prometheus/tsdb/labels"
 
-	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/prometheus/prometheus/pkg/timestamp"
 	pb "github.com/prometheus/prometheus/prompb"
 )
@@ -114,16 +113,6 @@ var (
 	maxTime = time.Unix(math.MaxInt64/1000-62135596801, 999999999)
 )
 
-func labelsToProto(lset labels.Labels) pb.Labels {
-	r := pb.Labels{
-		Labels: make([]pb.Label, 0, len(lset)),
-	}
-	for _, l := range lset {
-		r.Labels = append(r.Labels, pb.Label{Name: l.Name, Value: l.Value})
-	}
-	return r
-}
-
 // AdminDisabled implements the administration interface that informs
 // that the API endpoints are disabled.
 type AdminDisabled struct {

web/federate.go

@@ -90,7 +90,7 @@ func (h *Handler) federation(w http.ResponseWriter, req *http.Request) {
 		s, wrns, err := q.Select(params, mset...)
 		if wrns != nil {
 			level.Debug(h.logger).Log("msg", "federation select returned warnings", "warnings", wrns)
-			federationErrors.Add(float64(len(wrns)))
+			federationWarnings.Add(float64(len(wrns)))
 		}
 		if err != nil {
 			federationErrors.Inc()

web/web.go

@@ -124,20 +124,18 @@ type Handler struct {
 
 	apiV1 *api_v1.API
 
-	router       *route.Router
+	router      *route.Router
-	quitCh       chan struct{}
+	quitCh      chan struct{}
-	reloadCh     chan chan error
+	reloadCh    chan chan error
-	options      *Options
+	options     *Options
-	config       *config.Config
+	config      *config.Config
-	configString string
+	versionInfo *PrometheusVersion
-	versionInfo  *PrometheusVersion
+	birth       time.Time
-	birth        time.Time
+	cwd         string
-	cwd          string
+	flagsMap    map[string]string
-	flagsMap     map[string]string
 
-	externalLabels model.LabelSet
+	mtx sync.RWMutex
-	mtx            sync.RWMutex
+	now func() model.Time
-	now            func() model.Time
 
 	ready uint32 // ready is uint32 rather than boolean to be able to use atomic functions.
 }