fix: linked/depends-on container restarting (#1103)

internal/actions/update.go

@@ -9,6 +9,7 @@ import (
 	"github.com/containrrr/watchtower/pkg/sorter"
 	"github.com/containrrr/watchtower/pkg/types"
 	log "github.com/sirupsen/logrus"
+	"strings"
 )
 
 // Update looks at the running Docker containers to see if any of the images
@@ -68,7 +69,7 @@ func Update(client container.Client, params types.UpdateParams) (types.Report, e
 		return nil, err
 	}
 
-	checkDependencies(containers)
+	UpdateImplicitRestart(containers)
 
 	var containersToUpdate []container.Container
 	if !params.MonitorOnly {
@@ -216,24 +217,41 @@ func restartStaleContainer(container container.Container, client container.Clien
 	return nil
 }
 
-func checkDependencies(containers []container.Container) {
+// UpdateImplicitRestart iterates through the passed containers, setting the
+// `LinkedToRestarting` flag if any of it's linked containers are marked for restart
+func UpdateImplicitRestart(containers []container.Container) {
 
-	for _, c := range containers {
+	for ci, c := range containers {
 		if c.ToRestart() {
+			// The container is already marked for restart, no need to check
 			continue
 		}
 
-	LinkLoop:
-		for _, linkName := range c.Links() {
-			for _, candidate := range containers {
-				if candidate.Name() != linkName {
-					continue
-				}
-				if candidate.ToRestart() {
-					c.LinkedToRestarting = true
-					break LinkLoop
-				}
+		if link := linkedContainerMarkedForRestart(c.Links(), containers); link != "" {
+			log.WithFields(log.Fields{
+				"restarting": link,
+				"linked":     c.Name(),
+			}).Debug("container is linked to restarting")
+			// NOTE: To mutate the array, the `c` variable cannot be used as it's a copy
+			containers[ci].LinkedToRestarting = true
+		}
+
+	}
+}
+
+// linkedContainerMarkedForRestart returns the name of the first link that matches a
+// container marked for restart
+func linkedContainerMarkedForRestart(links []string, containers []container.Container) string {
+	for _, linkName := range links {
+		// Since the container names need to start with '/', let's prepend it if it's missing
+		if !strings.HasPrefix(linkName, "/") {
+			linkName = "/" + linkName
+		}
+		for _, candidate := range containers {
+			if candidate.Name() == linkName && candidate.ToRestart() {
+				return linkName
 			}
 		}
 	}
+	return ""
 }

internal/actions/update_test.go

@@ -20,6 +20,7 @@ var _ = Describe("the update action", func() {
 		BeforeEach(func() {
 			pullImages := false
 			removeVolumes := false
+			//goland:noinspection GoBoolExpressions
 			client = CreateMockClient(
 				&TestData{
 					NameOfContainerToKeep: "test-container-02",
@@ -255,6 +256,54 @@ var _ = Describe("the update action", func() {
 			})
 		})
 
+		When("container is linked to restarting containers", func() {
+			It("should be marked for restart", func() {
+
+				provider := CreateMockContainerWithConfig(
+					"test-container-provider",
+					"/test-container-provider",
+					"fake-image2:latest",
+					true,
+					false,
+					time.Now(),
+					&dockerContainer.Config{
+						Labels:       map[string]string{},
+						ExposedPorts: map[nat.Port]struct{}{},
+					})
+
+				provider.Stale = true
+
+				consumer := CreateMockContainerWithConfig(
+					"test-container-consumer",
+					"/test-container-consumer",
+					"fake-image3:latest",
+					true,
+					false,
+					time.Now(),
+					&dockerContainer.Config{
+						Labels: map[string]string{
+							"com.centurylinklabs.watchtower.depends-on": "test-container-provider",
+						},
+						ExposedPorts: map[nat.Port]struct{}{},
+					})
+
+				containers := []container.Container{
+					provider,
+					consumer,
+				}
+
+				Expect(provider.ToRestart()).To(BeTrue())
+				Expect(consumer.ToRestart()).To(BeFalse())
+
+				actions.UpdateImplicitRestart(containers)
+
+				Expect(containers[0].ToRestart()).To(BeTrue())
+				Expect(containers[1].ToRestart()).To(BeTrue())
+
+			})
+
+		})
+
 		When("container is not running", func() {
 			BeforeEach(func() {
 				client = CreateMockClient(