services/horizon: Add Stellar protocol version metrics

services/horizon/internal/app.go

@@ -57,6 +57,7 @@ type App struct {
 	historyElderLedgerCounter         prometheus.CounterFunc
 	coreLatestLedgerCounter           prometheus.CounterFunc
 	coreSynced                        prometheus.GaugeFunc
+	coreSupportedProtocolVersion      prometheus.GaugeFunc
 }
 
 func (a *App) GetCoreState() corestate.State {

services/horizon/internal/ingest/main.go

@@ -100,6 +100,10 @@ type stellarCoreClient interface {
 }
 
 type Metrics struct {
+	// MaxSupportedProtocolVersion exposes the maximum protocol version
+	// supported by this version.
+	MaxSupportedProtocolVersion prometheus.Gauge
+
 	// LocalLedger exposes the last ingested ledger by this ingesting instance.
 	LocalLatestLedger prometheus.Gauge
 
@@ -124,6 +128,10 @@ type Metrics struct {
 	// CaptiveStellarCoreSynced exposes synced status of Captive Stellar-Core.
 	// 1 if sync, 0 if not synced, -1 if unable to connect or HTTP server disabled.
 	CaptiveStellarCoreSynced prometheus.GaugeFunc
+
+	// CaptiveCoreSupportedProtocolVersion exposes the maximum protocol version
+	// supported by the running Captive-Core.
+	CaptiveCoreSupportedProtocolVersion prometheus.GaugeFunc
 }
 
 type System interface {
@@ -250,6 +258,13 @@ func NewSystem(config Config) (System, error) {
 }
 
 func (s *system) initMetrics() {
+	s.metrics.MaxSupportedProtocolVersion = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "horizon", Subsystem: "ingest", Name: "max_supported_protocol_version",
+		Help: "the maximum protocol version supported by this version.",
+	})
+
+	s.metrics.MaxSupportedProtocolVersion.Set(float64(MaxSupportedProtocolVersion))
+
 	s.metrics.LocalLatestLedger = prometheus.NewGauge(prometheus.GaugeOpts{
 		Namespace: "horizon", Subsystem: "ingest", Name: "local_latest_ledger",
 		Help: "sequence number of the latest ledger ingested by this ingesting instance",
@@ -330,6 +345,33 @@ func (s *system) initMetrics() {
 			}
 		},
 	)
+
+	s.metrics.CaptiveCoreSupportedProtocolVersion = prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Namespace: "horizon", Subsystem: "ingest", Name: "captive_stellar_core_supported_protocol_version",
+			Help: "determines the supported version of the protocol by Captive-Core",
+		},
+		func() float64 {
+			if !s.config.EnableCaptiveCore || (s.config.CaptiveCoreToml.HTTPPort == 0) {
+				return -1
+			}
+
+			client := stellarcore.Client{
+				HTTP: &http.Client{
+					Timeout: 2 * time.Second,
+				},
+				URL: fmt.Sprintf("http://localhost:%d", s.config.CaptiveCoreToml.HTTPPort),
+			}
+
+			info, err := client.Info(s.ctx)
+			if err != nil {
+				log.WithError(err).Error("Cannot connect to Captive Stellar-Core HTTP server")
+				return -1
+			}
+
+			return float64(info.Info.ProtocolVersion)
+		},
+	)
 }
 
 func (s *system) Metrics() Metrics {

services/horizon/internal/init.go

@@ -217,6 +217,17 @@ func initDbMetrics(app *App) {
 	)
 	app.prometheusRegistry.MustRegister(app.coreSynced)
 
+	app.coreSupportedProtocolVersion = prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Namespace: "horizon", Subsystem: "stellar_core", Name: "supported_protocol_version",
+			Help: "determines the supported version of the protocol by Stellar-Core defined by --stellar-core-url",
+		},
+		func() float64 {
+			return float64(app.coreState.Get().CoreSupportedProtocolVersion)
+		},
+	)
+	app.prometheusRegistry.MustRegister(app.coreSupportedProtocolVersion)
+
 	app.prometheusRegistry.MustRegister(app.orderBookStream.LatestLedgerGauge)
 }
 
@@ -243,13 +254,15 @@ func initIngestMetrics(app *App) {
 	}
 
 	app.ingestingGauge.Inc()
+	app.prometheusRegistry.MustRegister(app.ingester.Metrics().MaxSupportedProtocolVersion)
 	app.prometheusRegistry.MustRegister(app.ingester.Metrics().LocalLatestLedger)
 	app.prometheusRegistry.MustRegister(app.ingester.Metrics().LedgerIngestionDuration)
 	app.prometheusRegistry.MustRegister(app.ingester.Metrics().StateVerifyDuration)
 	app.prometheusRegistry.MustRegister(app.ingester.Metrics().StateInvalidGauge)
 	app.prometheusRegistry.MustRegister(app.ingester.Metrics().LedgerStatsCounter)
 	app.prometheusRegistry.MustRegister(app.ingester.Metrics().ProcessorsRunDuration)
 	app.prometheusRegistry.MustRegister(app.ingester.Metrics().CaptiveStellarCoreSynced)
+	app.prometheusRegistry.MustRegister(app.ingester.Metrics().CaptiveCoreSupportedProtocolVersion)
 }
 
 func initTxSubMetrics(app *App) {