refactor(update): clean up actions/update

- move common arguments to a shared struct
- remove unused fields
- fix outdated names
- improve logging/error handling

internal/actions/mocks/client.go

@@ -87,7 +87,7 @@ func (client MockClient) ExecuteCommand(_ t.ContainerID, command string, _ time.
 }
 
 // IsContainerStale is true if not explicitly stated in TestData for the mock client
-func (client MockClient) IsContainerStale(cont t.Container, params t.UpdateParams) (bool, t.ImageID, error) {
+func (client MockClient) IsContainerStale(cont t.Container, _ t.UpdateParams) (bool, t.ImageID, error) {
 	stale, found := client.TestData.Staleness[cont.Name()]
 	if !found {
 		stale = true

internal/actions/update.go

@@ -2,6 +2,7 @@ package actions
 
 import (
 	"errors"
+	"fmt"
 
 	"github.com/containrrr/watchtower/internal/util"
 	"github.com/containrrr/watchtower/pkg/container"
@@ -9,37 +10,52 @@ import (
 	"github.com/containrrr/watchtower/pkg/session"
 	"github.com/containrrr/watchtower/pkg/sorter"
 	"github.com/containrrr/watchtower/pkg/types"
+
 	log "github.com/sirupsen/logrus"
 )
 
+type updateSession struct {
+	client   container.Client
+	params   types.UpdateParams
+	progress *session.Progress
+}
+
 // Update looks at the running Docker containers to see if any of the images
 // used to start those containers have been updated. If a change is detected in
 // any of the images, the associated containers are stopped and restarted with
 // the new image.
 func Update(client container.Client, params types.UpdateParams) (types.Report, error) {
-	log.Debug("Checking containers for updated images")
-	progress := &session.Progress{}
-	staleCount := 0
+	log.Debug("Starting new update session")
+	us := updateSession{client: client, params: params, progress: &session.Progress{}}
 
-	if params.LifecycleHooks {
-		lifecycle.ExecutePreChecks(client, params)
-	}
+	us.TryExecuteLifecycleCommands(types.PreCheck)
 
-	containers, err := client.ListContainers(params.Filter)
-	if err != nil {
+	if err := us.run(); err != nil {
 		return nil, err
 	}
 
-	staleCheckFailed := 0
+	us.TryExecuteLifecycleCommands(types.PostCheck)
+
+	return us.progress.Report(), nil
+}
+
+func (us *updateSession) run() (err error) {
+
+	containers, err := us.client.ListContainers(us.params.Filter)
+	if err != nil {
+		return err
+	}
 
 	for i, targetContainer := range containers {
-		stale, newestImage, err := client.IsContainerStale(targetContainer, params)
-		shouldUpdate := stale && !params.NoRestart && !targetContainer.IsMonitorOnly(params)
+		stale, newestImage, err := us.client.IsContainerStale(targetContainer, us.params)
+		shouldUpdate := stale && !us.params.NoRestart && !targetContainer.IsMonitorOnly(us.params)
+
 		if err == nil && shouldUpdate {
 			// Check to make sure we have all the necessary information for recreating the container
 			err = targetContainer.VerifyConfiguration()
-			// If the image information is incomplete and trace logging is enabled, log it for further diagnosis
 			if err != nil && log.IsLevelEnabled(log.TraceLevel) {
+				// If the image information is incomplete and trace logging is enabled, log it for further diagnosis
+				log.WithError(err).Trace("Cannot obtain enough information to recreate container")
 				imageInfo := targetContainer.ImageInfo()
 				log.Tracef("Image info: %#v", imageInfo)
 				log.Tracef("Container info: %#v", targetContainer.ContainerInfo())
@@ -51,62 +67,52 @@ func Update(client container.Client, params types.UpdateParams) (types.Report, e
 
 		if err != nil {
 			log.Infof("Unable to update container %q: %v. Proceeding to next.", targetContainer.Name(), err)
-			stale = false
-			staleCheckFailed++
-			progress.AddSkipped(targetContainer, err)
+			us.progress.AddSkipped(targetContainer, err)
+			containers[i].SetMarkedForUpdate(false)
 		} else {
-			progress.AddScanned(targetContainer, newestImage)
-		}
-		containers[i].SetStale(stale)
-
-		if stale {
-			staleCount++
+			us.progress.AddScanned(targetContainer, newestImage)
+			containers[i].SetMarkedForUpdate(shouldUpdate)
 		}
 	}
 
 	containers, err = sorter.SortByDependencies(containers)
 	if err != nil {
-		return nil, err
+		return fmt.Errorf("failed to sort containers for updating: %v", err)
 	}
 
 	UpdateImplicitRestart(containers)
 
 	var containersToUpdate []types.Container
 	for _, c := range containers {
-		if !c.IsMonitorOnly(params) {
+		if c.ToRestart() {
 			containersToUpdate = append(containersToUpdate, c)
-			progress.MarkForUpdate(c.ID())
+			us.progress.MarkForUpdate(c.ID())
 		}
 	}
 
-	if params.RollingRestart {
-		progress.UpdateFailed(performRollingRestart(containersToUpdate, client, params))
+	if us.params.RollingRestart {
+		us.performRollingRestart(containersToUpdate)
 	} else {
-		failedStop, stoppedImages := stopContainersInReversedOrder(containersToUpdate, client, params)
-		progress.UpdateFailed(failedStop)
-		failedStart := restartContainersInSortedOrder(containersToUpdate, client, params, stoppedImages)
-		progress.UpdateFailed(failedStart)
+		stoppedImages := us.stopContainersInReversedOrder(containersToUpdate)
+		us.restartContainersInSortedOrder(containersToUpdate, stoppedImages)
 	}
 
-	if params.LifecycleHooks {
-		lifecycle.ExecutePostChecks(client, params)
-	}
-	return progress.Report(), nil
+	return nil
 }
 
-func performRollingRestart(containers []types.Container, client container.Client, params types.UpdateParams) map[types.ContainerID]error {
+func (us *updateSession) performRollingRestart(containers []types.Container) {
 	cleanupImageIDs := make(map[types.ImageID]bool, len(containers))
 	failed := make(map[types.ContainerID]error, len(containers))
 
 	for i := len(containers) - 1; i >= 0; i-- {
 		if containers[i].ToRestart() {
-			err := stopStaleContainer(containers[i], client, params)
+			err := us.stopContainer(containers[i])
 			if err != nil {
 				failed[containers[i].ID()] = err
 			} else {
-				if err := restartStaleContainer(containers[i], client, params); err != nil {
+				if err := us.restartContainer(containers[i]); err != nil {
 					failed[containers[i].ID()] = err
-				} else if containers[i].IsStale() {
+				} else if containers[i].IsMarkedForUpdate() {
 					// Only add (previously) stale containers' images to cleanup
 					cleanupImageIDs[containers[i].ImageID()] = true
 				}
@@ -114,17 +120,17 @@ func performRollingRestart(containers []types.Container, client container.Client
 		}
 	}
 
-	if params.Cleanup {
-		cleanupImages(client, cleanupImageIDs)
+	if us.params.Cleanup {
+		us.cleanupImages(cleanupImageIDs)
 	}
-	return failed
+	us.progress.UpdateFailed(failed)
 }
 
-func stopContainersInReversedOrder(containers []types.Container, client container.Client, params types.UpdateParams) (failed map[types.ContainerID]error, stopped map[types.ImageID]bool) {
-	failed = make(map[types.ContainerID]error, len(containers))
+func (us *updateSession) stopContainersInReversedOrder(containers []types.Container) (stopped map[types.ImageID]bool) {
+	failed := make(map[types.ContainerID]error, len(containers))
 	stopped = make(map[types.ImageID]bool, len(containers))
 	for i := len(containers) - 1; i >= 0; i-- {
-		if err := stopStaleContainer(containers[i], client, params); err != nil {
+		if err := us.stopContainer(containers[i]); err != nil {
 			failed[containers[i].ID()] = err
 		} else {
 			// NOTE: If a container is restarted due to a dependency this might be empty
@@ -132,47 +138,51 @@ func stopContainersInReversedOrder(containers []types.Container, client containe
 		}
 
 	}
-	return
+	us.progress.UpdateFailed(failed)
+
+	return stopped
 }
 
-func stopStaleContainer(container types.Container, client container.Client, params types.UpdateParams) error {
-	if container.IsWatchtower() {
-		log.Debugf("This is the watchtower container %s", container.Name())
+func (us *updateSession) stopContainer(c types.Container) error {
+	if c.IsWatchtower() {
+		log.Debugf("This is the watchtower container %s", c.Name())
 		return nil
 	}
 
-	if !container.ToRestart() {
+	if !c.ToRestart() {
 		return nil
 	}
 
 	// Perform an additional check here to prevent us from stopping a linked container we cannot restart
-	if container.IsLinkedToRestarting() {
-		if err := container.VerifyConfiguration(); err != nil {
+	if c.IsLinkedToRestarting() {
+		if err := c.VerifyConfiguration(); err != nil {
 			return err
 		}
 	}
 
-	if params.LifecycleHooks {
-		skipUpdate, err := lifecycle.ExecutePreUpdateCommand(client, container)
+	if us.params.LifecycleHooks {
+		err := lifecycle.ExecuteLifeCyclePhaseCommand(types.PreUpdate, us.client, c)
 		if err != nil {
+
+			if errors.Is(err, container.ErrorLifecycleSkip) {
+				log.Debug(err)
+				return err
+			}
+
 			log.Error(err)
 			log.Info("Skipping container as the pre-update command failed")
 			return err
 		}
-		if skipUpdate {
-			log.Debug("Skipping container as the pre-update command returned exit code 75 (EX_TEMPFAIL)")
-			return errors.New("skipping container as the pre-update command returned exit code 75 (EX_TEMPFAIL)")
-		}
 	}
 
-	if err := client.StopContainer(container, params.Timeout); err != nil {
+	if err := us.client.StopContainer(c, us.params.Timeout); err != nil {
 		log.Error(err)
 		return err
 	}
 	return nil
 }
 
-func restartContainersInSortedOrder(containers []types.Container, client container.Client, params types.UpdateParams, stoppedImages map[types.ImageID]bool) map[types.ContainerID]error {
+func (us *updateSession) restartContainersInSortedOrder(containers []types.Container, stoppedImages map[types.ImageID]bool) {
 	cleanupImageIDs := make(map[types.ImageID]bool, len(containers))
 	failed := make(map[types.ContainerID]error, len(containers))
 
@@ -181,58 +191,58 @@ func restartContainersInSortedOrder(containers []types.Container, client contain
 			continue
 		}
 		if stoppedImages[c.SafeImageID()] {
-			if err := restartStaleContainer(c, client, params); err != nil {
+			if err := us.restartContainer(c); err != nil {
 				failed[c.ID()] = err
-			} else if c.IsStale() {
+			} else if c.IsMarkedForUpdate() {
 				// Only add (previously) stale containers' images to cleanup
 				cleanupImageIDs[c.ImageID()] = true
 			}
 		}
 	}
 
-	if params.Cleanup {
-		cleanupImages(client, cleanupImageIDs)
+	if us.params.Cleanup {
+		us.cleanupImages(cleanupImageIDs)
 	}
 
-	return failed
+	us.progress.UpdateFailed(failed)
 }
 
-func cleanupImages(client container.Client, imageIDs map[types.ImageID]bool) {
+func (us *updateSession) cleanupImages(imageIDs map[types.ImageID]bool) {
 	for imageID := range imageIDs {
 		if imageID == "" {
 			continue
 		}
-		if err := client.RemoveImageByID(imageID); err != nil {
+		if err := us.client.RemoveImageByID(imageID); err != nil {
 			log.Error(err)
 		}
 	}
 }
 
-func restartStaleContainer(container types.Container, client container.Client, params types.UpdateParams) error {
-	// Since we can't shutdown a watchtower container immediately, we need to
-	// start the new one while the old one is still running. This prevents us
-	// from re-using the same container name so we first rename the current
-	// instance so that the new one can adopt the old name.
+func (us *updateSession) restartContainer(container types.Container) error {
 	if container.IsWatchtower() {
-		if err := client.RenameContainer(container, util.RandName()); err != nil {
+		// Since we can't shut down a watchtower container immediately, we need to
+		// start the new one while the old one is still running. This prevents us
+		// from re-using the same container name, so we first rename the current
+		// instance so that the new one can adopt the old name.
+		if err := us.client.RenameContainer(container, util.RandName()); err != nil {
 			log.Error(err)
 			return nil
 		}
 	}
 
-	if !params.NoRestart {
-		if newContainerID, err := client.StartContainer(container); err != nil {
+	if !us.params.NoRestart {
+		if newContainerID, err := us.client.StartContainer(container); err != nil {
 			log.Error(err)
 			return err
-		} else if container.ToRestart() && params.LifecycleHooks {
-			lifecycle.ExecutePostUpdateCommand(client, newContainerID)
+		} else if container.ToRestart() && us.params.LifecycleHooks {
+			lifecycle.ExecutePostUpdateCommand(us.client, newContainerID)
 		}
 	}
 	return nil
 }
 
 // UpdateImplicitRestart iterates through the passed containers, setting the
-// `LinkedToRestarting` flag if any of it's linked containers are marked for restart
+// `linkedToRestarting` flag if any of its linked containers are marked for restart
 func UpdateImplicitRestart(containers []types.Container) {
 
 	for ci, c := range containers {
@@ -265,3 +275,23 @@ func linkedContainerMarkedForRestart(links []string, containers []types.Containe
 	}
 	return ""
 }
+
+// TryExecuteLifecycleCommands tries to run the corresponding lifecycle hook for all containers included by the current filter.
+func (us *updateSession) TryExecuteLifecycleCommands(phase types.LifecyclePhase) {
+	if !us.params.LifecycleHooks {
+		return
+	}
+
+	containers, err := us.client.ListContainers(us.params.Filter)
+	if err != nil {
+		log.WithError(err).Warn("Skipping lifecycle commands. Failed to list containers.")
+		return
+	}
+
+	for _, c := range containers {
+		err := lifecycle.ExecuteLifeCyclePhaseCommand(phase, us.client, c)
+		if err != nil {
+			log.WithField("container", c.Name()).Error(err)
+		}
+	}
+}

pkg/container/client.go

@@ -396,7 +396,10 @@ func (client dockerClient) PullImage(ctx context.Context, container t.Container)
 		return err
 	}
 
-	defer response.Close()
+	defer func() {
+		_ = response.Close()
+	}()
+
 	// the pull request will be aborted prematurely unless the response is read
 	if _, err = io.ReadAll(response); err != nil {
 		log.Error(err)

pkg/lifecycle/lifecycle.go

@@ -6,29 +6,6 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-type ExecCommandFunc func(client container.Client, container types.Container)
-
-// ExecutePreCheckCommand tries to run the pre-check lifecycle hook for a single container.
-func ExecutePreCheckCommand(client container.Client, container types.Container) {
-	err := ExecuteLifeCyclePhaseCommand(types.PreCheck, client, container)
-	if err != nil {
-		log.WithField("container", container.Name()).Error(err)
-	}
-}
-
-// ExecutePostCheckCommand tries to run the post-check lifecycle hook for a single container.
-func ExecutePostCheckCommand(client container.Client, container types.Container) {
-	err := ExecuteLifeCyclePhaseCommand(types.PostCheck, client, container)
-	if err != nil {
-		log.WithField("container", container.Name()).Error(err)
-	}
-}
-
-// ExecutePreUpdateCommand tries to run the pre-update lifecycle hook for a single container.
-func ExecutePreUpdateCommand(client container.Client, container types.Container) error {
-	return ExecuteLifeCyclePhaseCommand(types.PreUpdate, client, container)
-}
-
 // ExecutePostUpdateCommand tries to run the post-update lifecycle hook for a single container.
 func ExecutePostUpdateCommand(client container.Client, newContainerID types.ContainerID) {
 	newContainer, err := client.GetContainer(newContainerID)