feat(dbmanager): ✨ Database connection Manager

pkg/dbmanager/metrics.go

@@ -0,0 +1,136 @@
+package dbmanager
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	// connectionsTotal tracks the total number of configured database connections
+	connectionsTotal = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "dbmanager_connections_total",
+			Help: "Total number of configured database connections",
+		},
+		[]string{"type"},
+	)
+
+	// connectionStatus tracks connection health status (1=healthy, 0=unhealthy)
+	connectionStatus = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "dbmanager_connection_status",
+			Help: "Connection status (1=healthy, 0=unhealthy)",
+		},
+		[]string{"name", "type"},
+	)
+
+	// connectionPoolSize tracks connection pool sizes
+	connectionPoolSize = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "dbmanager_connection_pool_size",
+			Help: "Current connection pool size",
+		},
+		[]string{"name", "type", "state"}, // state: open, idle, in_use
+	)
+
+	// connectionWaitCount tracks how many times connections had to wait for availability
+	connectionWaitCount = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "dbmanager_connection_wait_count",
+			Help: "Number of times connections had to wait for availability",
+		},
+		[]string{"name", "type"},
+	)
+
+	// connectionWaitDuration tracks total time connections spent waiting
+	connectionWaitDuration = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "dbmanager_connection_wait_duration_seconds",
+			Help: "Total time connections spent waiting for availability",
+		},
+		[]string{"name", "type"},
+	)
+
+	// reconnectAttempts tracks reconnection attempts and their outcomes
+	reconnectAttempts = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "dbmanager_reconnect_attempts_total",
+			Help: "Total number of reconnection attempts",
+		},
+		[]string{"name", "type", "result"}, // result: success, failure
+	)
+
+	// connectionLifetimeClosed tracks connections closed due to max lifetime
+	connectionLifetimeClosed = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "dbmanager_connection_lifetime_closed_total",
+			Help: "Total connections closed due to exceeding max lifetime",
+		},
+		[]string{"name", "type"},
+	)
+
+	// connectionIdleClosed tracks connections closed due to max idle time
+	connectionIdleClosed = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "dbmanager_connection_idle_closed_total",
+			Help: "Total connections closed due to exceeding max idle time",
+		},
+		[]string{"name", "type"},
+	)
+)
+
+// PublishMetrics publishes current metrics for all connections
+func (m *connectionManager) PublishMetrics() {
+	stats := m.Stats()
+
+	// Count connections by type
+	typeCount := make(map[DatabaseType]int)
+	for _, connStats := range stats.ConnectionStats {
+		typeCount[connStats.Type]++
+	}
+
+	// Update total connections gauge
+	for dbType, count := range typeCount {
+		connectionsTotal.WithLabelValues(string(dbType)).Set(float64(count))
+	}
+
+	// Update per-connection metrics
+	for name, connStats := range stats.ConnectionStats {
+		labels := prometheus.Labels{
+			"name": name,
+			"type": string(connStats.Type),
+		}
+
+		// Connection status
+		status := float64(0)
+		if connStats.Connected && connStats.HealthCheckStatus == "healthy" {
+			status = 1
+		}
+		connectionStatus.With(labels).Set(status)
+
+		// Pool size metrics (SQL databases only)
+		if connStats.Type != DatabaseTypeMongoDB {
+			connectionPoolSize.WithLabelValues(name, string(connStats.Type), "open").Set(float64(connStats.OpenConnections))
+			connectionPoolSize.WithLabelValues(name, string(connStats.Type), "idle").Set(float64(connStats.Idle))
+			connectionPoolSize.WithLabelValues(name, string(connStats.Type), "in_use").Set(float64(connStats.InUse))
+
+			// Wait stats
+			connectionWaitCount.With(labels).Set(float64(connStats.WaitCount))
+			connectionWaitDuration.With(labels).Set(connStats.WaitDuration.Seconds())
+
+			// Lifetime/idle closed
+			connectionLifetimeClosed.With(labels).Set(float64(connStats.MaxLifetimeClosed))
+			connectionIdleClosed.With(labels).Set(float64(connStats.MaxIdleClosed))
+		}
+	}
+}
+
+// RecordReconnectAttempt records a reconnection attempt
+func RecordReconnectAttempt(name string, dbType DatabaseType, success bool) {
+	result := "failure"
+	if success {
+		result = "success"
+	}
+
+	reconnectAttempts.WithLabelValues(name, string(dbType), result).Inc()
+}