Adding parameter to allow containers to be updated only after some number of days have passed since the new image has been published

cmd/root.go

@@ -39,6 +39,7 @@ var (
 	disableContainers []string
 	notifier          t.Notifier
 	timeout           time.Duration
+	delayDays         int
 	lifecycleHooks    bool
 	rollingRestart    bool
 	scope             string
@@ -96,6 +97,7 @@ func PreRun(cmd *cobra.Command, _ []string) {
 
 	enableLabel, _ = f.GetBool("label-enable")
 	disableContainers, _ = f.GetStringSlice("disable-containers")
+	delayDays, _ = f.GetInt("delay-days")
 	lifecycleHooks, _ = f.GetBool("enable-lifecycle-hooks")
 	rollingRestart, _ = f.GetBool("rolling-restart")
 	scope, _ = f.GetString("scope")
@@ -288,6 +290,10 @@ func writeStartupMessage(c *cobra.Command, sched time.Time, filtering string) {
 		until := formatDuration(time.Until(sched))
 		startupLog.Info("Scheduling first run: " + sched.Format("2006-01-02 15:04:05 -0700 MST"))
 		startupLog.Info("Note that the first check will be performed in " + until)
+		delayDays, _ = c.PersistentFlags().GetInt("delay-days")
+		if delayDays > 0 {
+			startupLog.Infof("Container updates will be delayed until %d day(s) after image creation.", delayDays)
+		}
 	} else if runOnce, _ := c.PersistentFlags().GetBool("run-once"); runOnce {
 		startupLog.Info("Running a one time update.")
 	} else {
@@ -364,6 +370,7 @@ func runUpdatesWithNotifications(filter t.Filter) *metrics.Metric {
 		NoRestart:       noRestart,
 		Timeout:         timeout,
 		MonitorOnly:     monitorOnly,
+		DelayDays:       delayDays,
 		LifecycleHooks:  lifecycleHooks,
 		RollingRestart:  rollingRestart,
 		LabelPrecedence: labelPrecedence,

docs/arguments.md

@@ -381,6 +381,16 @@ Environment Variable: WATCHTOWER_HTTP_API_METRICS
              Default: false
 ```
 
+## Delayed Update
+Only update container to latest version of image if some number of days have passed since it has been published. This option may be useful for those who wish to avoid updating prior to the new version having some time in the field prior to updating in case there are critical defects found and released in a subsequent version.
+
+```text
+            Argument: --delay-days
+Environment Variable: WATCHTOWER_DELAY_DAYS
+                Type: Integer
+             Default: false
+```
+
 ## Scheduling
 [Cron expression](https://pkg.go.dev/github.com/robfig/[email protected]?tab=doc#hdr-CRON_Expression_Format) in 6 fields (rather than the traditional 5) which defines when and how often to check for new images. Either `--interval` or the schedule expression
 can be defined, but not both. An example: `--schedule "0 0 4 * * *"`

internal/flags/flags.go

@@ -147,6 +147,12 @@ func RegisterSystemFlags(rootCmd *cobra.Command) {
 		envBool("WATCHTOWER_LIFECYCLE_HOOKS"),
 		"Enable the execution of commands triggered by pre- and post-update lifecycle hooks")
 
+	flags.IntP(
+		"delay-days",
+		"0",
+		envInt("WATCHTOWER_DELAY_DAYS"),
+		"Number of days to wait for new image version to be in place prior to installing it")
+
 	flags.BoolP(
 		"rolling-restart",
 		"",

internal/flags/flags_test.go

@@ -278,9 +278,9 @@ func TestProcessFlagAliasesInvalidPorcelaineVersion(t *testing.T) {
 	})
 }
 
-func TestFlagsArePrecentInDocumentation(t *testing.T) {
+func TestFlagsArePresentInDocumentation(t *testing.T) {
 
-	// Legacy notifcations are ignored, since they are (soft) deprecated
+	// Legacy notifications are ignored, since they are (soft) deprecated
 	ignoredEnvs := map[string]string{
 		"WATCHTOWER_NOTIFICATION_SLACK_ICON_EMOJI": "legacy",
 		"WATCHTOWER_NOTIFICATION_SLACK_ICON_URL":   "legacy",

pkg/container/client.go

@@ -325,10 +325,25 @@ func (client dockerClient) IsContainerStale(container t.Container, params t.Upda
 		return false, container.SafeImageID(), err
 	}
 
-	return client.HasNewImage(ctx, container)
+	return client.HasNewImage(ctx, container, params)
 }
 
-func (client dockerClient) HasNewImage(ctx context.Context, container t.Container) (hasNew bool, latestImage t.ImageID, err error) {
+// Date strings sometimes vary in how many digits after the decimal point are present. This function
+// standardizes them by removing the milliseconds.
+func truncateMilliseconds(dateString string) string {
+	// Find the position of the dot (.) in the date string
+	dotIndex := strings.Index(dateString, ".")
+
+	// If the dot is found, truncate the string before the dot
+	if dotIndex != -1 {
+		return dateString[:dotIndex] + "Z"
+	}
+
+	// If the dot is not found, return the original string
+	return dateString
+}
+
+func (client dockerClient) HasNewImage(ctx context.Context, container t.Container, params t.UpdateParams) (hasNew bool, latestImage t.ImageID, err error) {
 	currentImageID := t.ImageID(container.ContainerInfo().ContainerJSONBase.Image)
 	imageName := container.ImageName()
 
@@ -343,6 +358,26 @@ func (client dockerClient) HasNewImage(ctx context.Context, container t.Containe
 		return false, currentImageID, nil
 	}
 
+	// Disabled by default
+	if params.DelayDays > 0 {
+		// Define the layout string for the date format without milliseconds
+		layout := "2006-01-02T15:04:05Z"
+		newImageDate, error := time.Parse(layout, truncateMilliseconds(newImageInfo.Created))
+
+		if error != nil {
+			log.Errorf("Error parsing Created date (%s) for container %s latest label. Error: %s", newImageInfo.Created, container.Name(), error)
+			return false, currentImageID, nil
+		} else {
+			requiredDays := params.DelayDays
+			diffDays := int(time.Since(newImageDate).Hours() / 24)
+
+			if diffDays < requiredDays {
+				log.Infof("New image found for %s that was created %d day(s) ago but update delayed until %d day(s) after creation", container.Name(), diffDays, requiredDays)
+				return false, currentImageID, nil
+			}
+		}
+	}
+
 	log.Infof("Found new %s image (%s)", imageName, newImageID.ShortID())
 	return true, newImageID, nil
 }

pkg/types/update_params.go

@@ -11,7 +11,8 @@ type UpdateParams struct {
 	NoRestart       bool
 	Timeout         time.Duration
 	MonitorOnly     bool
-	NoPull			bool
+	NoPull          bool
+	DelayDays       int
 	LifecycleHooks  bool
 	RollingRestart  bool
 	LabelPrecedence bool