Add Slack Channel, IconEmoji, and IconURL options (#241)

README.md

@@ -274,6 +274,11 @@ Additionally, you should set the Slack webhook url using the `--notification-sla
 
 By default, watchtower will send messages under the name `watchtower`, you can customize this string through the `--notification-slack-identifier` option or the `WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER` environment variable.
 
+Other, optional, variables include:
+- `--notification-slack-channel` (env. `WATCHTOWER_NOTIFICATION_SLACK_CHANNEL`): A string which overrides the webhook's default channel. Example: #my-custom-channel.
+- `--notification-slack-icon-emoji` (env. `WATCHTOWER_NOTIFICATION_SLACK_ICON_EMOJI`): An [emoji code](https://www.webpagefx.com/tools/emoji-cheat-sheet/) string to use in place of the default icon.
+- `--notification-slack-icon-url` (env. `WATCHTOWER_NOTIFICATION_SLACK_ICON_URL`): An icon image URL string to use in place of the default icon.
+
 Example:
 
 ```bash
@@ -283,6 +288,9 @@ docker run -d \
   -e WATCHTOWER_NOTIFICATIONS=slack \
   -e WATCHTOWER_NOTIFICATION_SLACK_HOOK_URL="https://hooks.slack.com/services/xxx/yyyyyyyyyyyyyyy" \
   -e WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER=watchtower-server-1 \
+  -e WATCHTOWER_NOTIFICATION_SLACK_CHANNEL=#my-custom-channel \
+  -e WATCHTOWER_NOTIFICATION_SLACK_ICON_EMOJI=:whale: \
+  -e WATCHTOWER_NOTIFICATION_SLACK_ICON_URL=<icon url> \
   containrrr/watchtower
 ```
 

main.go

@@ -162,6 +162,21 @@ func main() {
 			EnvVar: "WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER",
 			Value:  "watchtower",
 		},
+		cli.StringFlag{
+			Name:   "notification-slack-channel",
+			Usage:  "A string which overrides the webhook's default channel. Example: #my-custom-channel",
+			EnvVar: "WATCHTOWER_NOTIFICATION_SLACK_CHANNEL",
+		},
+		cli.StringFlag{
+			Name:   "notification-slack-icon-emoji",
+			Usage:  "An emoji code string to use in place of the default icon",
+			EnvVar: "WATCHTOWER_NOTIFICATION_SLACK_ICON_EMOJI",
+		},
+		cli.StringFlag{
+			Name:   "notification-slack-icon-url",
+			Usage:  "An icon image URL string to use in place of the default icon",
+			EnvVar: "WATCHTOWER_NOTIFICATION_SLACK_ICON_URL",
+		},
 		cli.StringFlag{
 			Name:   "notification-msteams-hook",
 			Usage:  "The MSTeams WebHook URL to send notifications to",

notifications/slack.go

@@ -19,6 +19,9 @@ func newSlackNotifier(c *cli.Context, acceptedLogLevels []log.Level) typeNotifie
 		SlackrusHook: slackrus.SlackrusHook{
 			HookURL:        c.GlobalString("notification-slack-hook-url"),
 			Username:       c.GlobalString("notification-slack-identifier"),
+			Channel:        c.GlobalString("notification-slack-channel"),
+			IconEmoji:      c.GlobalString("notification-slack-icon-emoji"),
+			IconURL:        c.GlobalString("notification-slack-icon-url"),
 			AcceptedLevels: acceptedLogLevels,
 		},
 	}