Feat/lifecycle hooks (#351)

* feat(update): add lifecycle hooks to the update action

* fix(ci): add bash tests for lifecycle-hooks to the ci workflow

* fix(ci): move integration tests to an isolated step

* fix(ci): fix malformed all-contributors json

* fix(ci): disable automatic bash test until we figure out a reasonable way to run it in circleci

internal/actions/actions_suite_test.go

@@ -160,7 +160,7 @@ func (client mockClient) StopContainer(c container.Container, d time.Duration) e
 	}
 	return nil
 }
-func (client mockClient) StartContainer(c container.Container) error {
+func (client mockClient) StartContainer(c container.Container) (string, error) {
 	panic("Not implemented")
 }
 
@@ -173,6 +173,14 @@ func (client mockClient) RemoveImage(c container.Container) error {
 	return nil
 }
 
+func (client mockClient) GetContainer(containerID string) (container.Container, error) {
+	return container.Container{}, nil
+}
+
+func (client mockClient) ExecuteCommand(containerID string, command string) error {
+	return nil
+}
+
 func (client mockClient) IsContainerStale(c container.Container) (bool, error) {
 	panic("Not implemented")
 }

internal/actions/update.go

@@ -61,8 +61,9 @@ func stopStaleContainer(container container.Container, client container.Client,
 		return
 	}
 
-	err := client.StopContainer(container, params.Timeout)
-	if err != nil {
+	executePreUpdateCommand(client, container)
+
+	if err := client.StopContainer(container, params.Timeout); err != nil {
 		log.Error(err)
 	}
 }
@@ -89,8 +90,10 @@ func restartStaleContainer(container container.Container, client container.Clien
 	}
 
 	if !params.NoRestart {
-		if err := client.StartContainer(container); err != nil {
+		if newContainerID, err := client.StartContainer(container); err != nil {
 			log.Error(err)
+		} else if container.Stale && params.LifecycleHooks {
+			executePostUpdateCommand(client, newContainerID)
 		}
 	}
 
@@ -104,18 +107,49 @@ func restartStaleContainer(container container.Container, client container.Clien
 func checkDependencies(containers []container.Container) {
 
 	for i, parent := range containers {
-		if parent.Stale {
+		if parent.ToRestart() {
 			continue
 		}
 
 	LinkLoop:
 		for _, linkName := range parent.Links() {
 			for _, child := range containers {
-				if child.Name() == linkName && child.Stale {
-					containers[i].Stale = true
+				if child.Name() == linkName && child.ToRestart() {
+					containers[i].Linked = true
 					break LinkLoop
 				}
 			}
 		}
 	}
 }
+
+func executePreUpdateCommand(client container.Client, container container.Container) {
+
+	command := container.GetLifecyclePreUpdateCommand()
+	if len(command) == 0 {
+		log.Debug("No pre-update command supplied. Skipping")
+	}
+
+	log.Info("Executing pre-update command.")
+	if err := client.ExecuteCommand(container.ID(), command); err != nil {
+		log.Error(err)
+	}
+}
+
+func executePostUpdateCommand(client container.Client, newContainerID string) {
+	newContainer, err := client.GetContainer(newContainerID)
+	if err != nil {
+		log.Error(err)
+		return
+	}
+
+	command := newContainer.GetLifecyclePostUpdateCommand()
+	if len(command) == 0 {
+		log.Debug("No post-update command supplied. Skipping")
+	}
+
+	log.Info("Executing post-update command.")
+	if err := client.ExecuteCommand(newContainerID, command); err != nil {
+		log.Error(err)
+	}
+}

internal/actions/update_params.go

@@ -7,9 +7,10 @@ import (
 
 // UpdateParams contains all different options available to alter the behavior of the Update func
 type UpdateParams struct {
-	Filter      t.Filter
-	Cleanup     bool
-	NoRestart   bool
-	Timeout     time.Duration
-	MonitorOnly bool
+	Filter         t.Filter
+	Cleanup        bool
+	NoRestart      bool
+	Timeout        time.Duration
+	MonitorOnly    bool
+	LifecycleHooks bool
 }

internal/flags/flags.go

@@ -88,6 +88,12 @@ func RegisterSystemFlags(rootCmd *cobra.Command) {
 		"S",
 		viper.GetBool("WATCHTOWER_INCLUDE_STOPPED"),
 		"Will also include created and exited containers")
+
+	flags.BoolP(
+		"enable-lifecycle-hooks",
+		"",
+		viper.GetBool("WATCHTOWER_LIFECYCLE_HOOKS"),
+		"Enable the execution of commands triggered by pre- and post-update lifecycle hooks")
 }
 
 // RegisterNotificationFlags that are used by watchtower to send notifications