[#565] Add metrics for current GRPC endpoint status

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

pkg/metrics/consts.go

@@ -19,6 +19,7 @@ const (
 	stateSubsystem          = "state"
 	treeServiceSubsystem    = "treeservice"
 	writeCacheSubsystem     = "writecache"
+	grpcServerSubsystem     = "grpc_server"
 
 	successLabel          = "success"
 	shardIDLabel          = "shard_id"
@@ -35,6 +36,7 @@ const (
 	containerIDLabelKey   = "cid"
 	storageLabel          = "storage"
 	operationLabel        = "operation"
+	endpointLabel         = "endpoint"
 
 	readWriteMode = "READ_WRITE"
 	readOnlyMode  = "READ_ONLY"

pkg/metrics/grpc.go

@@ -0,0 +1,35 @@
+package metrics
+
+import (
+	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type GrpcServerMetrics interface {
+	MarkHealthy(endpoint string)
+	MarkUnhealthy(endpoint string)
+}
+
+type grpcServerMetrics struct {
+	endpointHealth *prometheus.GaugeVec
+}
+
+func newGrpcServerMetrics() *grpcServerMetrics {
+	return &grpcServerMetrics{
+		endpointHealth: metrics.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: namespace,
+				Subsystem: grpcServerSubsystem,
+				Name:      "health",
+				Help:      "GRPC Server Endpoint health",
+			}, []string{endpointLabel}),
+	}
+}
+
+func (m *grpcServerMetrics) MarkHealthy(endpoint string) {
+	m.endpointHealth.With(prometheus.Labels{endpointLabel: endpoint}).Set(float64(1))
+}
+
+func (m *grpcServerMetrics) MarkUnhealthy(endpoint string) {
+	m.endpointHealth.With(prometheus.Labels{endpointLabel: endpoint}).Set(float64(0))
+}

pkg/metrics/node.go

@@ -17,6 +17,7 @@ type NodeMetrics struct {
 	blobobvnizca  *blobovnizca
 	metabase      *metabaseMetrics
 	pilorama      *piloramaMetrics
+	grpc          *grpcServerMetrics
 }
 
 func NewNodeMetrics() *NodeMetrics {
@@ -37,6 +38,7 @@ func NewNodeMetrics() *NodeMetrics {
 		blobobvnizca: newBlobovnizca(),
 		metabase:     newMetabaseMetrics(),
 		pilorama:     newPiloramaMetrics(),
+		grpc:         newGrpcServerMetrics(),
 	}
 }
 
@@ -84,3 +86,7 @@ func (m *NodeMetrics) MetabaseMetrics() MetabaseMetrics {
 func (m *NodeMetrics) PiloramaMetrics() PiloramaMetrics {
 	return m.pilorama
 }
+
+func (m *NodeMetrics) GrpcServerMetrics() GrpcServerMetrics {
+	return m.grpc
+}