Recover DB connection automatically after network returns

internal/db/connection.go

@@ -94,6 +94,8 @@ func (cm *ConnectionManager) GetDB() (*gorm.DB, error) {
 	// Attempt to connect
 	err := cm.connect()
 	if err != nil {
+		// Drop stale handle so callers don't treat it as an active connection.
+		cm.db = nil
 		cm.lastError = err
 		cm.lastCheck = time.Now()
 		return nil, err
@@ -147,23 +149,27 @@ func (cm *ConnectionManager) connect() error {
 	return nil
 }
 
-// IsOnline checks if the database is currently connected and responsive
-// Does not attempt to reconnect, only checks current state with caching
+// IsOnline checks if the database is currently connected and responsive.
+// If disconnected, it tries to reconnect (respecting cooldowns in GetDB).
 func (cm *ConnectionManager) IsOnline() bool {
 	cm.mu.RLock()
-	if cm.db == nil {
-		cm.mu.RUnlock()
-		return false
-	}
-
-	// If we've checked recently, return cached result
-	if time.Since(cm.lastCheck) < cm.pingInterval {
-		cm.mu.RUnlock()
-		return true
-	}
+	isDisconnected := cm.db == nil
+	lastErr := cm.lastError
+	checkedRecently := time.Since(cm.lastCheck) < cm.pingInterval
 	cm.mu.RUnlock()
 
-	// Need to perform actual ping
+	// Try reconnect in disconnected state.
+	if isDisconnected {
+		_, err := cm.GetDB()
+		return err == nil
+	}
+
+	// If we've checked recently, return cached result.
+	if checkedRecently {
+		return lastErr == nil
+	}
+
+	// Need to perform actual ping.
 	cm.mu.Lock()
 	defer cm.mu.Unlock()
 
@@ -282,7 +288,7 @@ func extractHostFromDSN(dsn string) string {
 		}
 		if parenEnd != -1 {
 			// Extract host:port part between tcp( and )
-			hostPort := dsn[tcpStart+1:parenEnd]
+			hostPort := dsn[tcpStart+1 : parenEnd]
 			return hostPort
 		}
 	}
@@ -317,7 +323,7 @@ func extractHostFromDSN(dsn string) string {
 			}
 
 			if parenEnd != -1 {
-				hostPort := dsn[parenStart+1:parenEnd]
+				hostPort := dsn[parenStart+1 : parenEnd]
 				return hostPort
 			}
 		}