Add networkobservability_build_info Prometheus metric

pkg/metrics/metrics.go

@@ -3,6 +3,9 @@
 package metrics
 
 import (
+	"runtime"
+
+	"github.com/microsoft/retina/internal/buildinfo"
 	"github.com/microsoft/retina/pkg/exporter"
 	"github.com/microsoft/retina/pkg/log"
 	"github.com/microsoft/retina/pkg/utils"
@@ -194,6 +197,23 @@ func InitializeMetrics() {
 		parsedPacketsCounterDescription,
 	)
 
+	// Build Info metric - set to 1 with version and architecture labels
+	BuildInfo = exporter.CreatePrometheusGaugeVecForMetric(
+		exporter.DefaultRegistry,
+		utils.BuildInfoName,
+		BuildInfoDescription,
+		utils.BuildVersion,
+		utils.BuildArchitecture,
+		utils.BuildOS,
+	)
+	// Set the build info to 1 with the current build information
+	// Use "unknown" as fallback if version is not set during build
+	version := buildinfo.Version
+	if version == "" {
+		version = "unknown"
+	}
+	BuildInfo.WithLabelValues(version, runtime.GOARCH, runtime.GOOS).Set(1)
+
 	isInitialized = true
 	metricsLogger.Info("Metrics initialized")
 }

pkg/metrics/metrics_test.go

@@ -4,9 +4,11 @@
 package metrics
 
 import (
+	"runtime"
 	"testing"
 
 	"github.com/microsoft/retina/pkg/log"
+	dto "github.com/prometheus/client_model/go"
 )
 
 func TestInitialization_FirstInit(t *testing.T) {
@@ -15,7 +17,7 @@
 	InitializeMetrics()
 
 	//  All metrics should be initialized.
-	objs := []interface{}{DropPacketsGauge, DropBytesGauge, ForwardBytesGauge, ForwardPacketsGauge, NodeConnectivityStatusGauge, NodeConnectivityLatencyGauge, PluginManagerFailedToReconcileCounter}
+	objs := []interface{}{DropPacketsGauge, DropBytesGauge, ForwardBytesGauge, ForwardPacketsGauge, NodeConnectivityStatusGauge, NodeConnectivityLatencyGauge, PluginManagerFailedToReconcileCounter, BuildInfo}
 	for _, obj := range objs {
 		if obj == nil {
 			t.Fatalf("Expected all metrics to be initialized")
@@ -35,3 +37,34 @@
 	// Should not panic when reinitializing.
 	InitializeMetrics()
 }
+
+func TestBuildInfo(t *testing.T) {
+	log.SetupZapLogger(log.GetDefaultLogOpts())
+
+	InitializeMetrics()
+
+	if BuildInfo == nil {
+		t.Fatalf("Expected BuildInfo to be initialized")
+	}
+
+	// Verify that the build info gauge has been set with runtime information
+	// Note: buildinfo.Version is populated via ldflags during build, so in tests it will
+	// use the "unknown" fallback. The actual version label is tested in integration tests
+	// or when running a built binary.
+	metric := &dto.Metric{}
+	// Use the actual runtime values that were used to set the metric
+	err := BuildInfo.WithLabelValues("unknown", runtime.GOARCH, runtime.GOOS).Write(metric)
+	if err != nil {
+		t.Fatalf("Failed to write metric: %v", err)
+	}
+
+	if metric.Gauge == nil {
+		t.Fatalf("Expected gauge metric, got nil")
+	}
+
+	if *metric.Gauge.Value != 1 {
+		t.Errorf("Expected gauge value to be 1, got %f", *metric.Gauge.Value)
+	}
+
+	t.Logf("✓ BuildInfo metric correctly set to 1 with labels: version=unknown, arch=%s, os=%s", runtime.GOARCH, runtime.GOOS)
+}

pkg/metrics/types.go

@@ -52,6 +52,9 @@ const (
 	ConntrackBytesTxDescription          = "Number of tx bytes"
 	ConntrackBytesRxDescription          = "Number of rx bytes"
 	ConntrackTotalConnectionsDescription = "Total number of connections"
+
+	// Build info
+	BuildInfoDescription = "Retina build information"
 )
 
 // Metric Counters
@@ -107,6 +110,9 @@ var (
 	ConntrackBytesTx          GaugeVec
 	ConntrackBytesRx          GaugeVec
 	ConntrackTotalConnections GaugeVec
+
+	// Build Info
+	BuildInfo GaugeVec
 )
 
 func ToPrometheusType(metric interface{}) prometheus.Collector {

pkg/utils/attr_utils.go

@@ -48,6 +48,11 @@ var (
 	Active                = "ACTIVE"
 	Device                = "device"
 
+	// Build Info labels
+	BuildVersion      = "version"
+	BuildArchitecture = "architecture"
+	BuildOS           = "os"
+
 	// TCP Connection Statistic Names
 	ResetCount           = "ResetCount"
 	ClosedFin            = "ClosedFin"

pkg/utils/metric_names.go

@@ -41,6 +41,9 @@ const (
 	ConntrackBytesTxGaugeName     = "conntrack_bytes_tx"
 	ConntrackBytesRxGaugeName     = "conntrack_bytes_rx"
 	ConntrackTotalConnectionsName = "conntrack_total_connections"
+
+	// Build Info
+	BuildInfoName = "build_info"
 )
 
 // IsAdvancedMetric is a helper function to determine if a name is an advanced metric