Changeset 0.33.0 (#207)

Co-authored-by: Jeffrey Smith <jasafpro@gmail.com>
Co-committed-by: Jeffrey Smith <jasafpro@gmail.com>

server/metrics/db_collector.go

@@ -0,0 +1,26 @@
+package metrics
+
+import (
+	"database/sql"
+	"time"
+)
+
+// StartDBCollector begins a background goroutine that reads sql.DBStats
+// every interval and updates the Prometheus DB pool gauges.
+func StartDBCollector(db *sql.DB, interval time.Duration) {
+	if db == nil {
+		return
+	}
+	go func() {
+		ticker := time.NewTicker(interval)
+		defer ticker.Stop()
+		for range ticker.C {
+			stats := db.Stats()
+			DBOpenConnections.Set(float64(stats.OpenConnections))
+			DBInUseConnections.Set(float64(stats.InUse))
+			DBIdleConnections.Set(float64(stats.Idle))
+			DBWaitCount.Set(float64(stats.WaitCount))
+			DBWaitDuration.Set(stats.WaitDuration.Seconds())
+		}
+	}()
+}