watchtower/docs/notifications.md

Notifications

Watchtower can send notifications when containers are updated. Notifications are sent via hooks in the logging system, logrus. The types of notifications to send are set by passing a comma-separated list of values to the --notifications option (or corresponding environment variable WATCHTOWER_NOTIFICATIONS), which has the following valid values:

• email to send notifications via e-mail
• slack to send notifications through a Slack webhook
• msteams to send notifications via MSTeams webhook
• gotify to send notifications via Gotify

There is currently a bug in Viper, which prevents comma-separated slices to be used when using the environment variable. A workaround is available where we instead put quotes around the environment variable value and replace the commas with spaces, as WATCHTOWER_NOTIFICATIONS="slack msteams"

If you're a docker-compose user, make sure to specify environment variables' values in your .yml file without double quotes (").

This prevents unexpected errors when watchtower starts.

Settings

• --notifications-level (env. WATCHTOWER_NOTIFICATIONS_LEVEL): Controls the log level which is used for the notifications. If omitted, the default log level is info. Possible values are: panic, fatal, error, warn, info or debug.
• Whatchtower will post a notification every time is started. This behavior can be changed with an argument.

Available services

Email

To receive notifications by email, the following command-line options, or their corresponding environment variables, can be set:

• --notification-email-from (env. WATCHTOWER_NOTIFICATION_EMAIL_FROM): The e-mail address from which notifications will be sent.
• --notification-email-to (env. WATCHTOWER_NOTIFICATION_EMAIL_TO): The e-mail address to which notifications will be sent.
• --notification-email-server (env. WATCHTOWER_NOTIFICATION_EMAIL_SERVER): The SMTP server to send e-mails through.
• --notification-email-server-tls-skip-verify (env. WATCHTOWER_NOTIFICATION_EMAIL_SERVER_TLS_SKIP_VERIFY): Do not verify the TLS certificate of the mail server. This should be used only for testing.
• --notification-email-server-port (env. WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT): The port used to connect to the SMTP server to send e-mails through. Defaults to 25.
• --notification-email-server-user (env. WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER): The username to authenticate with the SMTP server with.
• --notification-email-server-password (env. WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD): The password to authenticate with the SMTP server with.
• --notification-email-delay (env. WATCHTOWER_NOTIFICATION_EMAIL_DELAY): Delay before sending notifications expressed in seconds.
• --notification-email-subjecttag (env. WATCHTOWER_NOTIFICATION_EMAIL_SUBJECTTAG): Prefix to include in the subject tag. Useful when running multiple watchtowers.

Example:

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=email \
  -e WATCHTOWER_NOTIFICATION_EMAIL_FROM=fromaddress@gmail.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_TO=toaddress@gmail.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER=smtp.gmail.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER=fromaddress@gmail.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD=app_password \
  -e WATCHTOWER_NOTIFICATION_EMAIL_DELAY=2 \
  containrrr/watchtower

Slack

If watchtower is monitoring the same Docker daemon under which the watchtower container itself is running (i.e. if you volume-mounted /var/run/docker.sock into the watchtower container) then it has the ability to update itself. If a new version of the containrrr/watchtower image is pushed to the Docker Hub, your watchtower will pull down the new image and restart itself automatically.

To receive notifications in Slack, add slack to the --notifications option or the WATCHTOWER_NOTIFICATIONS environment variable.

Additionally, you should set the Slack webhook URL using the --notification-slack-hook-url option or the WATCHTOWER_NOTIFICATION_SLACK_HOOK_URL environment variable.

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 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:

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -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

Microsoft Teams

To receive notifications in MSTeams channel, add msteams to the --notifications option or the WATCHTOWER_NOTIFICATIONS environment variable.

Additionally, you should set the MSTeams webhook URL using the --notification-msteams-hook option or the WATCHTOWER_NOTIFICATION_MSTEAMS_HOOK_URL environment variable.

MSTeams notifier could send keys/values filled by log.WithField or log.WithFields as MSTeams message facts. To enable this feature add --notification-msteams-data flag or set WATCHTOWER_NOTIFICATION_MSTEAMS_USE_LOG_DATA=true environment variable.

Example:

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=msteams \
  -e WATCHTOWER_NOTIFICATION_MSTEAMS_HOOK_URL="https://outlook.office.com/webhook/xxxxxxxx@xxxxxxx/IncomingWebhook/yyyyyyyy/zzzzzzzzzz" \
  -e WATCHTOWER_NOTIFICATION_MSTEAMS_USE_LOG_DATA=true \
  containrrr/watchtower

Gotify

To push a notification to your Gotify instance, register a Gotify app and specify the Gotify URL and app token:

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=gotify \
  -e WATCHTOWER_NOTIFICATION_GOTIFY_URL="https://my.gotify.tld/" \
  -e WATCHTOWER_NOTIFICATION_GOTIFY_TOKEN="SuperSecretToken" \
  containrrr/watchtower