feat(notifications): support delayed sending (#1142)

pkg/notifications/email.go

@@ -82,6 +82,10 @@ func (e *emailTypeNotifier) GetURL(c *cobra.Command) (string, error) {
 	return conf.GetURL().String(), nil
 }
 
+func (e *emailTypeNotifier) GetDelay() time.Duration {
+	return e.delay
+}
+
 func (e *emailTypeNotifier) getSubject(c *cobra.Command) string {
 	subject := GetTitle(c)
 

pkg/notifications/notifier.go

@@ -1,11 +1,13 @@
 package notifications
 
 import (
+	"os"
+	"time"
+
 	ty "github.com/containrrr/watchtower/pkg/types"
 	"github.com/johntdyer/slackrus"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
-	"os"
 )
 
 // NewNotifier creates and returns a new Notifier, using global configuration.
@@ -28,14 +30,14 @@ func NewNotifier(c *cobra.Command) ty.Notifier {
 	tplString, _ := f.GetString("notification-template")
 	urls, _ := f.GetStringArray("notification-url")
 
-	urls = AppendLegacyUrls(urls, c)
+	urls, delay := AppendLegacyUrls(urls, c)
 
 	title := GetTitle(c)
-	return newShoutrrrNotifier(tplString, acceptedLogLevels, !reportTemplate, title, urls...)
+	return newShoutrrrNotifier(tplString, acceptedLogLevels, !reportTemplate, title, delay, urls...)
 }
 
 // AppendLegacyUrls creates shoutrrr equivalent URLs from legacy notification flags
-func AppendLegacyUrls(urls []string, cmd *cobra.Command) []string {
+func AppendLegacyUrls(urls []string, cmd *cobra.Command) ([]string, time.Duration) {
 
 	// Parse types and create notifiers.
 	types, err := cmd.Flags().GetStringSlice("notifications")
@@ -43,6 +45,8 @@ func AppendLegacyUrls(urls []string, cmd *cobra.Command) []string {
 		log.WithError(err).Fatal("could not read notifications argument")
 	}
 
+	delay := time.Duration(0)
+
 	for _, t := range types {
 
 		var legacyNotifier ty.ConvertibleNotifier
@@ -71,9 +75,13 @@ func AppendLegacyUrls(urls []string, cmd *cobra.Command) []string {
 		}
 		urls = append(urls, shoutrrrURL)
 
+		if delayNotifier, ok := legacyNotifier.(ty.DelayNotifier); ok {
+			delay = delayNotifier.GetDelay()
+		}
+
 		log.WithField("URL", shoutrrrURL).Trace("created Shoutrrr URL from legacy notifier")
 	}
-	return urls
+	return urls, delay
 }
 
 // GetTitle returns a common notification title with hostname appended

pkg/notifications/notifier_test.go

@@ -241,7 +241,7 @@ func testURL(args []string, expectedURL string) {
 	err := command.ParseFlags(args)
 	Expect(err).NotTo(HaveOccurred())
 
-	urls := notifications.AppendLegacyUrls([]string{}, command)
+	urls, _ := notifications.AppendLegacyUrls([]string{}, command)
 
 	Expect(err).NotTo(HaveOccurred())
 

pkg/notifications/shoutrrr.go

@@ -5,6 +5,7 @@ import (
 	stdlog "log"
 	"strings"
 	"text/template"
+	"time"
 
 	"github.com/containrrr/shoutrrr"
 	"github.com/containrrr/shoutrrr/pkg/types"
@@ -77,14 +78,14 @@ func (n *shoutrrrTypeNotifier) GetNames() []string {
 	return names
 }
 
-func newShoutrrrNotifier(tplString string, acceptedLogLevels []log.Level, legacy bool, title string, urls ...string) t.Notifier {
+func newShoutrrrNotifier(tplString string, acceptedLogLevels []log.Level, legacy bool, title string, delay time.Duration, urls ...string) t.Notifier {
 
 	notifier := createNotifier(urls, acceptedLogLevels, tplString, legacy)
 	notifier.params = &types.Params{"title": title}
 	log.AddHook(notifier)
 
 	// Do the sending in a separate goroutine so we don't block the main process.
-	go sendNotifications(notifier)
+	go sendNotifications(notifier, delay)
 
 	return notifier
 }
@@ -112,8 +113,9 @@ func createNotifier(urls []string, levels []log.Level, tplString string, legacy
 	}
 }
 
-func sendNotifications(n *shoutrrrTypeNotifier) {
+func sendNotifications(n *shoutrrrTypeNotifier, delay time.Duration) {
 	for msg := range n.messages {
+		time.Sleep(delay)
 		errs := n.Router.Send(msg, n.params)
 
 		for i, err := range errs {

pkg/notifications/shoutrrr_test.go

@@ -1,6 +1,8 @@
 package notifications
 
 import (
+	"time"
+
 	"github.com/containrrr/shoutrrr/pkg/types"
 	"github.com/containrrr/watchtower/internal/actions/mocks"
 	"github.com/containrrr/watchtower/internal/flags"
@@ -212,7 +214,7 @@ Turns out everything is on fire
 	When("batching notifications", func() {
 		When("no messages are queued", func() {
 			It("should not send any notification", func() {
-				shoutrrr := newShoutrrrNotifier("", allButTrace, true, "", "logger://")
+				shoutrrr := newShoutrrrNotifier("", allButTrace, true, "", time.Duration(0), "logger://")
 				shoutrrr.StartNotification()
 				shoutrrr.SendNotification(nil)
 				Consistently(logBuffer).ShouldNot(gbytes.Say(`Shoutrrr:`))
@@ -220,7 +222,7 @@ Turns out everything is on fire
 		})
 		When("at least one message is queued", func() {
 			It("should send a notification", func() {
-				shoutrrr := newShoutrrrNotifier("", allButTrace, true, "", "logger://")
+				shoutrrr := newShoutrrrNotifier("", allButTrace, true, "", time.Duration(0), "logger://")
 				shoutrrr.StartNotification()
 				logrus.Info("This log message is sponsored by ContainrrrVPN")
 				shoutrrr.SendNotification(nil)
@@ -282,7 +284,7 @@ func sendNotificationsWithBlockingRouter(legacy bool) (*shoutrrrTypeNotifier, *b
 		Message: "foo bar",
 	}
 
-	go sendNotifications(shoutrrr)
+	go sendNotifications(shoutrrr, time.Duration(0))
 
 	shoutrrr.StartNotification()
 	_ = shoutrrr.Fire(entry)

pkg/types/convertible_notifier.go

@@ -1,8 +1,16 @@
 package types
 
-import "github.com/spf13/cobra"
+import (
+	"github.com/spf13/cobra"
+	"time"
+)
 
 // ConvertibleNotifier is a notifier capable of creating a shoutrrr URL
 type ConvertibleNotifier interface {
 	GetURL(c *cobra.Command) (string, error)
 }
+
+// DelayNotifier is a notifier that might need to be delayed before sending notifications
+type DelayNotifier interface {
+	GetDelay() time.Duration
+}