Use 'defer' to simplify handling of AppNetworkStatus pending flags

Currently, we have to remember to set PendingAdd/PendingModify inside
AppNetworkStatus to false just before the corresponding handler returns.
However, there are few error branches where we forgot to clear
the pending flag. This causes zedmanager to just wait and not report
the error published inside the AppNetworkStatus.
Instead of fixing this case-by-case, let's take advantage of 'defer'
to make sure that we will never forget to clear the Pending flag,
even if a new branch with return statement is added in the future.

Signed-off-by: Milan Lenco <milan@zededa.com>
(cherry picked from commit fbacc17)

pkg/pillar/cmd/zedrouter/appnetwork.go

@@ -140,8 +140,6 @@ func (z *zedrouter) doActivateAppNetwork(config types.AppNetworkConfig,
 
 	// Update AppNetwork and NetworkInstance status.
 	status.Activated = true
-	status.PendingAdd = false
-	status.PendingModify = false
 	z.publishAppNetworkStatus(status)
 	z.updateNIStatusAfterAppNetworkActivate(status)
 
@@ -307,7 +305,6 @@ func (z *zedrouter) doUpdateActivatedAppNetwork(oldConfig, newConfig types.AppNe
 	// Update app network status as well as status of connected network instances.
 	z.processAppConnReconcileStatus(appConnRecStatus, status)
 	z.reloadStatusOfAssignedIPs(status)
-	status.PendingModify = false
 	z.publishAppNetworkStatus(status)
 	z.updateNIStatusAfterAppNetworkActivate(status)
 }
@@ -335,8 +332,6 @@ func (z *zedrouter) doInactivateAppNetwork(config types.AppNetworkConfig,
 
 	// Update AppNetwork and NetworkInstance status.
 	status.Activated = false
-	status.PendingModify = false
-	status.PendingDelete = false
 	z.updateNIStatusAfterAppNetworkInactivate(status)
 	z.removeAssignedIPsFromAppNetStatus(status)
 	z.publishAppNetworkStatus(status)

pkg/pillar/cmd/zedrouter/pubsubhandlers.go

@@ -439,15 +439,19 @@ func (z *zedrouter) handleAppNetworkCreate(ctxArg interface{}, key string,
 	// Start by marking with PendingAdd
 	status := types.AppNetworkStatus{
 		UUIDandVersion: config.UUIDandVersion,
-		PendingAdd:     true,
 		DisplayName:    config.DisplayName,
 	}
 	z.doCopyAppNetworkConfigToStatus(config, &status)
+	status.PendingAdd = true
+	z.publishAppNetworkStatus(&status)
+	defer func() {
+		status.PendingAdd = false
+		z.publishAppNetworkStatus(&status)
+	}()
 
 	if err := z.validateAppNetworkConfig(config); err != nil {
 		z.log.Errorf("handleAppNetworkCreate(%v): validation failed: %v",
 			config.UUIDandVersion.UUID, err)
-		status.PendingAdd = false
 		z.addAppNetworkError(&status, "handleAppNetworkCreate", err)
 		return
 	}
@@ -460,7 +464,6 @@ func (z *zedrouter) handleAppNetworkCreate(ctxArg interface{}, key string,
 		err = fmt.Errorf("failed to allocate appNum for %s/%s: %v",
 			config.UUIDandVersion.UUID, config.DisplayName, err)
 		z.log.Errorf("handleAppNetworkCreate(%v): %v", config.UUIDandVersion.UUID, err)
-		status.PendingAdd = false
 		z.addAppNetworkError(&status, "handleAppNetworkCreate", err)
 		return
 	}
@@ -474,7 +477,6 @@ func (z *zedrouter) handleAppNetworkCreate(ctxArg interface{}, key string,
 		err = fmt.Errorf("failed to allocate numbers for VIFs of the app %s/%s: %v",
 			config.UUIDandVersion.UUID, config.DisplayName, err)
 		z.log.Errorf("handleAppNetworkCreate(%v): %v", config.UUIDandVersion.UUID, err)
-		status.PendingAdd = false
 		z.addAppNetworkError(&status, "handleAppNetworkCreate", err)
 		return
 	}
@@ -485,20 +487,14 @@ func (z *zedrouter) handleAppNetworkCreate(ctxArg interface{}, key string,
 	if err != nil {
 		z.log.Errorf("handleAppNetworkCreate(%v): %v", config.UUIDandVersion.UUID, err)
 		status.AwaitNetworkInstance = true
-		status.PendingAdd = false
 		if netInErrState {
 			z.addAppNetworkError(&status, "handleAppNetworkCreate", err)
-		} else {
-			z.publishAppNetworkStatus(&status)
 		}
 		return
 	}
 
 	if config.Activate {
 		z.doActivateAppNetwork(config, &status)
-	} else {
-		status.PendingAdd = false
-		z.publishAppNetworkStatus(&status)
 	}
 
 	z.maybeScheduleRetry()
@@ -519,12 +515,15 @@ func (z *zedrouter) handleAppNetworkModify(ctxArg interface{}, key string,
 	status.ClearError()
 	status.PendingModify = true
 	z.publishAppNetworkStatus(status)
+	defer func() {
+		status.PendingModify = false
+		z.publishAppNetworkStatus(status)
+	}()
 
 	// Check for unsupported/invalid changes.
 	if err := z.validateAppNetworkConfigForModify(newConfig, oldConfig); err != nil {
 		z.log.Errorf("handleAppNetworkModify(%v): validation failed: %v",
 			newConfig.UUIDandVersion.UUID, err)
-		status.PendingModify = false
 		z.addAppNetworkError(status, "handleAppNetworkModify", err)
 		return
 	}
@@ -538,27 +537,21 @@ func (z *zedrouter) handleAppNetworkModify(ctxArg interface{}, key string,
 	if err != nil {
 		z.log.Errorf("handleAppNetworkModify(%v): %v", newConfig.UUIDandVersion.UUID, err)
 		status.AwaitNetworkInstance = true
-		status.PendingModify = false
 		if netInErrState {
 			z.addAppNetworkError(status, "handleAppNetworkModify", err)
-		} else {
-			z.publishAppNetworkStatus(status)
 		}
 		return
 	}
 
 	if !newConfig.Activate && status.Activated {
 		z.doInactivateAppNetwork(newConfig, status)
 		z.doCopyAppNetworkConfigToStatus(newConfig, status)
-		z.publishAppNetworkStatus(status)
 	} else if newConfig.Activate && !status.Activated {
 		z.doCopyAppNetworkConfigToStatus(newConfig, status)
 		z.doActivateAppNetwork(newConfig, status)
 	} else if !status.Activated {
 		// Just copy in newConfig
 		z.doCopyAppNetworkConfigToStatus(newConfig, status)
-		status.PendingModify = false
-		z.publishAppNetworkStatus(status)
 	} else { // Config change while application network is active.
 		z.doUpdateActivatedAppNetwork(oldConfig, newConfig, status)
 	}
@@ -584,6 +577,8 @@ func (z *zedrouter) handleAppNetworkDelete(ctxArg interface{}, key string,
 
 	// Deactivate app network if it is currently activated.
 	if status.Activated {
+		// No need to clear PendingDelete later. Instead, we un-publish
+		// the status completely few lines below.
 		status.PendingDelete = true
 		z.publishAppNetworkStatus(status)
 		z.doInactivateAppNetwork(config, status)