feat : only sync if kafka-connect is running (#66)

* only sync if kafka-connect is running

Signed-off-by: Mark deVilliers <markdevilliers@gmail.com>

pkg/manager/manage.go

@@ -12,22 +12,30 @@ import (
 // Manage will start the connector manager running and managing connectors
 func (c *ConnectorManager) Manage(source ConnectorSource, stopCH <-chan struct{}) error {
 	// mark ourselves as having an unhealthy state until we have
-	// tried to contact the kafka-connect instance
+	// successfully configured the kafka-connect instance
 	c.readinessState = errorState
 
 	syncChannel := time.NewTicker(c.config.SyncPeriod).C
 	for {
 		select {
 		case <-syncChannel:
-			err := c.Sync(source)
-			if err != nil {
-				// set back into an unhealthy state
-				c.readinessState = errorState
-				return errors.Wrap(err, "error synchronising connectors for source")
+
+			// we only want to try Syncing if we can contact the kafka-connect instance.
+			// Using the LivenessCheck as a proxy for calculating the connection
+			if c.livenessState == okState {
+				err := c.Sync(source)
+				if err != nil {
+					// set back into an unhealthy state
+					c.readinessState = errorState
+					return errors.Wrap(err, "error synchronising connectors for source")
+				}
+				// mark ourselves as being in an ok state as we have
+				// started syncing without any error
+				c.readinessState = okState
+			} else {
+				c.logger.Infof("skipping sync as livenessState == %v", c.livenessState)
 			}
-			// mark ourselves as being in an ok state as we have
-			// started syncing without any error
-			c.readinessState = okState
+
 		case <-stopCH:
 			return nil
 		}

pkg/manager/manager.go

@@ -32,7 +32,8 @@ type ConnectorManager struct {
 	client client
 	logger Logger
 
-	readinessState readinessState
+	readinessState healthcheckState
+	livenessState  healthcheckState
 }
 
 // Option can be supplied that override the default ConnectorManager properties
@@ -52,6 +53,7 @@ func NewConnectorsManager(client client, config *Config, opts ...Option) (*Conne
 		client:         client,
 		logger:         newNoopLogger(),
 		readinessState: unknownState,
+		livenessState:  unknownState,
 	}
 
 	for _, opt := range opts {
@@ -61,10 +63,10 @@ func NewConnectorsManager(client client, config *Config, opts ...Option) (*Conne
 	return cm, nil
 }
 
-type readinessState int
+type healthcheckState int
 
 const (
-	unknownState readinessState = iota
+	unknownState healthcheckState = iota
 	okState
 	errorState
 )
@@ -91,9 +93,11 @@ func (c *ConnectorManager) LivenessCheck() (string, func() error) {
 	check := func() error {
 		err := healthcheck.HTTPGetCheck(c.config.ClusterURL, time.Second*2)()
 		if err != nil {
+			c.livenessState = errorState
 			c.logger.Infof("healthcheck: liveness : %s", err.Error())
 			return err
 		}
+		c.livenessState = okState
 		c.logger.Infof("healthcheck: liveness : ok")
 		return nil
 	}