Rename indexer metrics related to get operations (#853)

Rename indexer get metrics (histogram) to be specific to each
type of indexer. Currently, file system, zip and storage indexers.
Each indexer type is going to be included as a label in the metric.

Fixed options filter to check whether or not it is nil.

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Return only the latest version of each package when a combined index is used. [#849](https://github.com/elastic/package-registry/pull/849)
 * Return only first appearance of the same version of a package when it is available in multiple indexes. [#849](https://github.com/elastic/package-registry/pull/849)
+* Rename indexer metrics related to get operations and add the indexer name label to it. [#853](https://github.com/elastic/package-registry/pull/853)
 
 ### Added
 

indexer.go

@@ -7,11 +7,9 @@ package main
 import (
 	"context"
 	"sort"
-	"time"
 
 	"github.com/Masterminds/semver/v3"
 
-	"github.com/elastic/package-registry/metrics"
 	"github.com/elastic/package-registry/packages"
 )
 
@@ -37,8 +35,6 @@ func (c CombinedIndexer) Init(ctx context.Context) error {
 }
 
 func (c CombinedIndexer) Get(ctx context.Context, opts *packages.GetOptions) (packages.Packages, error) {
-	start := time.Now()
-	defer metrics.StorageIndexerGetDurationSeconds.Observe(time.Since(start).Seconds())
 	var packages packages.Packages
 	for _, indexer := range c {
 		p, err := indexer.Get(ctx, opts)
@@ -48,7 +44,7 @@ func (c CombinedIndexer) Get(ctx context.Context, opts *packages.GetOptions) (pa
 		packages = packages.Join(p)
 	}
 
-	if !opts.Filter.AllVersions {
+	if opts != nil && opts.Filter != nil && !opts.Filter.AllVersions {
 		return latestPackagesVersion(packages), nil
 	}
 

main.go

@@ -68,7 +68,7 @@ var (
 func init() {
 	flag.BoolVar(&printVersionInfo, "version", false, "Print Elastic Package Registry version")
 	flag.StringVar(&address, "address", "localhost:8080", "Address of the package-registry service.")
-	flag.StringVar(&metricsAddress, "metrics-address", "", "Address to expose the Prometheus metrics.")
+	flag.StringVar(&metricsAddress, "metrics-address", "", "Address to expose the Prometheus metrics (experimental). ")
 	flag.StringVar(&tlsCertFile, "tls-cert", "", "Path of the TLS certificate.")
 	flag.StringVar(&tlsKeyFile, "tls-key", "", "Path of the TLS key.")
 	flag.StringVar(&configPath, "config", "config.yml", "Path to the configuration file.")

metrics/metrics.go

@@ -39,32 +39,33 @@ var (
 		prometheus.CounterOpts{
 			Namespace: metricsNamespace,
 			Name:      "storage_indexer_update_index_success_total",
-			Help:      "A counter for updates of the cursor.",
+			Help:      "A counter for all the updates index of the cursor that finished successfully in the storage indexer.",
 		},
 	)
 
 	StorageIndexerUpdateIndexErrorsTotal = prometheus.NewCounter(
 		prometheus.CounterOpts{
 			Namespace: metricsNamespace,
 			Name:      "storage_indexer_update_index_error_total",
-			Help:      "A counter for all the update index processes that finished with error.",
+			Help:      "A counter for all the update index of the cursor that finished with error in the storage indexer.",
 		},
 	)
 
 	StorageIndexerUpdateIndexDurationSeconds = prometheus.NewHistogram(
 		prometheus.HistogramOpts{
 			Namespace: metricsNamespace,
 			Name:      "storage_indexer_update_index_duration_seconds",
-			Help:      "A histogram of latencies for update index processes run by the indexer.",
+			Help:      "A histogram of latencies for update index processes run by the storage indexer.",
 		},
 	)
 
-	StorageIndexerGetDurationSeconds = prometheus.NewHistogram(
+	IndexerGetDurationSeconds = prometheus.NewHistogramVec(
 		prometheus.HistogramOpts{
 			Namespace: metricsNamespace,
-			Name:      "storage_indexer_get_duration_seconds",
+			Name:      "indexer_get_duration_seconds",
 			Help:      "A histogram of latencies for get processes run by the indexer.",
 		},
+		[]string{"indexer"},
 	)
 )
 

metrics/middleware.go

@@ -25,7 +25,7 @@ func MetricsMiddleware() mux.MiddlewareFunc {
 
 	prometheus.MustRegister(NumberIndexedPackages)
 	prometheus.MustRegister(StorageRequestsTotal)
-	prometheus.MustRegister(StorageIndexerGetDurationSeconds)
+	prometheus.MustRegister(IndexerGetDurationSeconds)
 	prometheus.MustRegister(StorageIndexerUpdateIndexDurationSeconds)
 	prometheus.MustRegister(StorageIndexerUpdateIndexSuccessTotal)
 	prometheus.MustRegister(StorageIndexerUpdateIndexErrorsTotal)

packages/http.go

@@ -18,18 +18,31 @@ import (
 	"github.com/elastic/package-registry/util"
 )
 
+const (
+	localLocationPrometheusLabel  = "local"
+	remoteLocationPrometheusLabel = "remote"
+
+	artifactComponentPrometheusLabel  = "artifacts"
+	staticComponentPrometheusLabel    = "statics"
+	signatureComponentPrometheusLabel = "signatures"
+)
+
 // ServePackage is used by artifactsHandler to serve packages and signatures.
 func ServePackage(w http.ResponseWriter, r *http.Request, p *Package) {
 	span, _ := apm.StartSpan(r.Context(), "ServePackage", "app")
 	defer span.End()
 
 	if p.RemoteResolver() != nil {
 		p.RemoteResolver().RedirectArtifactsHandler(w, r, p)
-		metrics.StorageRequestsTotal.With(prometheus.Labels{"location": "remote", "component": "artifacts"}).Inc()
+		metrics.StorageRequestsTotal.With(
+			prometheus.Labels{"location": remoteLocationPrometheusLabel, "component": artifactComponentPrometheusLabel},
+		).Inc()
 		return
 	}
 	serveLocalPackage(w, r, p, p.BasePath)
-	metrics.StorageRequestsTotal.With(prometheus.Labels{"location": "local", "component": "artifacts"}).Inc()
+	metrics.StorageRequestsTotal.With(
+		prometheus.Labels{"location": localLocationPrometheusLabel, "component": artifactComponentPrometheusLabel},
+	).Inc()
 }
 
 // ServePackageSignature is used by signaturesHandler to serve signatures.
@@ -39,11 +52,15 @@ func ServePackageSignature(w http.ResponseWriter, r *http.Request, p *Package) {
 
 	if p.RemoteResolver() != nil {
 		p.RemoteResolver().RedirectSignaturesHandler(w, r, p)
-		metrics.StorageRequestsTotal.With(prometheus.Labels{"location": "remote", "component": "signatures"}).Inc()
+		metrics.StorageRequestsTotal.With(
+			prometheus.Labels{"location": remoteLocationPrometheusLabel, "component": signatureComponentPrometheusLabel},
+		).Inc()
 		return
 	}
 	serveLocalPackage(w, r, p, p.BasePath+".sig")
-	metrics.StorageRequestsTotal.With(prometheus.Labels{"location": "local", "component": "signatures"}).Inc()
+	metrics.StorageRequestsTotal.With(
+		prometheus.Labels{"location": localLocationPrometheusLabel, "component": signatureComponentPrometheusLabel},
+	).Inc()
 }
 
 func serveLocalPackage(w http.ResponseWriter, r *http.Request, p *Package, packagePath string) {
@@ -82,7 +99,9 @@ func ServePackageResource(w http.ResponseWriter, r *http.Request, p *Package, pa
 
 	if p.RemoteResolver() != nil {
 		p.RemoteResolver().RedirectStaticHandler(w, r, p, packageFilePath)
-		metrics.StorageRequestsTotal.With(prometheus.Labels{"location": "remote", "component": "static"}).Inc()
+		metrics.StorageRequestsTotal.With(
+			prometheus.Labels{"location": remoteLocationPrometheusLabel, "component": staticComponentPrometheusLabel},
+		).Inc()
 		return
 	}
 
@@ -119,5 +138,7 @@ func ServePackageResource(w http.ResponseWriter, r *http.Request, p *Package, pa
 	defer f.Close()
 
 	http.ServeContent(w, r, packageFilePath, stat.ModTime(), f)
-	metrics.StorageRequestsTotal.With(prometheus.Labels{"location": "local", "component": "static"}).Inc()
+	metrics.StorageRequestsTotal.With(
+		prometheus.Labels{"location": localLocationPrometheusLabel, "component": staticComponentPrometheusLabel},
+	).Inc()
 }

packages/packages.go

@@ -10,12 +10,15 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"github.com/Masterminds/semver/v3"
 	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
 	"go.elastic.co/apm"
 	"go.uber.org/zap"
 
+	"github.com/elastic/package-registry/metrics"
 	"github.com/elastic/package-registry/util"
 )
 
@@ -192,6 +195,8 @@ func (i *FileSystemIndexer) Init(ctx context.Context) (err error) {
 // This assumes changes to packages only happen on restart (unless development mode is enabled).
 // Caching the packages request many file reads every time this method is called.
 func (i *FileSystemIndexer) Get(ctx context.Context, opts *GetOptions) (Packages, error) {
+	start := time.Now()
+	defer metrics.IndexerGetDurationSeconds.With(prometheus.Labels{"indexer": i.label}).Observe(time.Since(start).Seconds())
 	if opts == nil {
 		return i.packageList, nil
 	}

storage/indexer.go

@@ -14,13 +14,16 @@ import (
 
 	"cloud.google.com/go/storage"
 	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
 	"go.uber.org/zap"
 
 	"github.com/elastic/package-registry/metrics"
 	"github.com/elastic/package-registry/packages"
 	"github.com/elastic/package-registry/util"
 )
 
+const indexerGetDurationPrometheusLabel = "StorageIndexer"
+
 type Indexer struct {
 	options       IndexerOptions
 	storageClient *storage.Client
@@ -173,6 +176,9 @@ func (i *Indexer) updateIndex(ctx context.Context) error {
 }
 
 func (i *Indexer) Get(ctx context.Context, opts *packages.GetOptions) (packages.Packages, error) {
+	start := time.Now()
+	defer metrics.IndexerGetDurationSeconds.With(prometheus.Labels{"indexer": indexerGetDurationPrometheusLabel}).Observe(time.Since(start).Seconds())
+
 	i.m.RLock()
 	defer i.m.RUnlock()