fix: high cardinality policy_violations metrics (#1)

* fix: high cardinality policy_violations metrics The exporter initialises all possible labels of dependency_track_project_policy_violations metrics which adds 72 metrics for each project. jetstack#53 has details of the rational but there are usecases where it is desirable to only have non-zero values of the metrics available. This change adds a new argument that enables only non-zero value metrics to be returned. This flag defaults to the current behaviour so is an opt in feature. * docs: add flag to readme
dwalker-sabiogroup · Aug 3, 2024 · 5c03ea7 · 5c03ea7
1 parent b4b3d3c
commit 5c03ea7
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diff --git a/README.md b/README.md
@@ -18,6 +18,8 @@ Flags:
                             Dependency-Track server address (default: http://localhost:8080 or $DEPENDENCY_TRACK_ADDR)
       --dtrack.api-key=DTRACK.API-KEY
                             Dependency-Track API key (default: $DEPENDENCY_TRACK_API_KEY)
+      --[no-]exporter.reduce-policy-cardinality  
+                            Initialize all policy_violations metric label values (can also be set with $EXPORTER_REDUCE_POLICY_CARDINALITY)
       --log.level=info      Only log messages with the given severity or above. One of: [debug, info, warn, error]
       --log.format=logfmt   Output format of log messages. One of: [logfmt, json]
       --version             Show application version.

diff --git a/internal/exporter/exporter.go b/internal/exporter/exporter.go
@@ -20,8 +20,9 @@ const (
 
 // Exporter exports metrics from a Dependency-Track server
 type Exporter struct {
-	Client *dtrack.Client
-	Logger log.Logger
+	Client                  *dtrack.Client
+	Logger                  log.Logger
+	ReducePolicyCardinality bool
 }
 
 // HandlerFunc handles requests to /metrics
@@ -235,28 +236,30 @@ func (e *Exporter) collectProjectMetrics(ctx context.Context, registry *promethe
 
 		// Initialize all the possible violation series with a 0 value so that it
 		// properly records increments from 0 -> 1
-		for _, possibleType := range []string{"LICENSE", "OPERATIONAL", "SECURITY"} {
-			for _, possibleState := range []string{"INFO", "WARN", "FAIL"} {
-				for _, possibleAnalysis := range []dtrack.ViolationAnalysisState{
-					dtrack.ViolationAnalysisStateApproved,
-					dtrack.ViolationAnalysisStateRejected,
-					dtrack.ViolationAnalysisStateNotSet,
-					// If there isn't any analysis for a policy
-					// violation then the value in the UI is
-					// actually empty. So let's represent that in
-					// these metrics as a possible analysis state.
-					"",
-				} {
-					for _, possibleSuppressed := range []string{"true", "false"} {
-						policyViolations.With(prometheus.Labels{
-							"uuid":       project.UUID.String(),
-							"name":       project.Name,
-							"version":    project.Version,
-							"type":       possibleType,
-							"state":      possibleState,
-							"analysis":   string(possibleAnalysis),
-							"suppressed": possibleSuppressed,
-						})
+		if e.ReducePolicyCardinality {
+			for _, possibleType := range []string{"LICENSE", "OPERATIONAL", "SECURITY"} {
+				for _, possibleState := range []string{"INFO", "WARN", "FAIL"} {
+					for _, possibleAnalysis := range []dtrack.ViolationAnalysisState{
+						dtrack.ViolationAnalysisStateApproved,
+						dtrack.ViolationAnalysisStateRejected,
+						dtrack.ViolationAnalysisStateNotSet,
+						// If there isn't any analysis for a policy
+						// violation then the value in the UI is
+						// actually empty. So let's represent that in
+						// these metrics as a possible analysis state.
+						"",
+					} {
+						for _, possibleSuppressed := range []string{"true", "false"} {
+							policyViolations.With(prometheus.Labels{
+								"uuid":       project.UUID.String(),
+								"name":       project.Name,
+								"version":    project.Version,
+								"type":       possibleType,
+								"state":      possibleState,
+								"analysis":   string(possibleAnalysis),
+								"suppressed": possibleSuppressed,
+							})
+						}
 					}
 				}
 			}

diff --git a/main.go b/main.go
@@ -20,8 +20,9 @@ import (
 )
 
 const (
-	envAddress string = "DEPENDENCY_TRACK_ADDR"
-	envAPIKey  string = "DEPENDENCY_TRACK_API_KEY"
+	envAddress                         string = "DEPENDENCY_TRACK_ADDR"
+	envAPIKey                          string = "DEPENDENCY_TRACK_API_KEY"
+	envExporterReducePolicyCardinality string = "EXPORTER_REDUCE_POLICY_CARDINALITY"
 )
 
 func init() {
@@ -30,11 +31,12 @@ func init() {
 
 func main() {
 	var (
-		webConfig     = webflag.AddFlags(kingpin.CommandLine, ":9916")
-		metricsPath   = kingpin.Flag("web.metrics-path", "Path under which to expose metrics").Default("/metrics").String()
-		dtAddress     = kingpin.Flag("dtrack.address", fmt.Sprintf("Dependency-Track server address (can also be set with $%s)", envAddress)).Default("http://localhost:8080").Envar(envAddress).String()
-		dtAPIKey      = kingpin.Flag("dtrack.api-key", fmt.Sprintf("Dependency-Track API key (can also be set with $%s)", envAPIKey)).Envar(envAPIKey).Required().String()
-		promlogConfig = promlog.Config{}
+		webConfig                       = webflag.AddFlags(kingpin.CommandLine, ":9916")
+		metricsPath                     = kingpin.Flag("web.metrics-path", "Path under which to expose metrics").Default("/metrics").String()
+		dtAddress                       = kingpin.Flag("dtrack.address", fmt.Sprintf("Dependency-Track server address (can also be set with $%s)", envAddress)).Default("http://localhost:8080").Envar(envAddress).String()
+		dtAPIKey                        = kingpin.Flag("dtrack.api-key", fmt.Sprintf("Dependency-Track API key (can also be set with $%s)", envAPIKey)).Envar(envAPIKey).Required().String()
+		exporterReducePolicyCardinality = kingpin.Flag("exporter.reduce-policy-cardinality", fmt.Sprintf("Initialize all policy_violations metric label values (can also be set with $%s)", envExporterReducePolicyCardinality)).Envar(envExporterReducePolicyCardinality).Default("true").Bool()
+		promlogConfig                   = promlog.Config{}
 	)
 
 	flag.AddFlags(kingpin.CommandLine, &promlogConfig)
@@ -54,8 +56,9 @@ func main() {
 	}
 
 	e := exporter.Exporter{
-		Client: c,
-		Logger: logger,
+		Client:                  c,
+		Logger:                  logger,
+		ReducePolicyCardinality: *exporterReducePolicyCardinality,
 	}
 
 	http.HandleFunc(*metricsPath, e.HandlerFunc())