<p>Watchtower can send notifications when containers are updated. Notifications are sent via hooks in the logging system, <ahref="http://github.com/sirupsen/logrus">logrus</a>.
The types of notifications to send are set by passing a comma-separated list of values to the <code>--notifications</code> option (or corresponding environment variable <code>WATCHTOWER_NOTIFICATIONS</code>), which has the following valid values:</p>
<p>There is currently a <ahref="https://github.com/spf13/viper/issues/380">bug</a> 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 <code>WATCHTOWER_NOTIFICATIONS="slack msteams"</code></p>
<p>If you're a <code>docker-compose</code> user, make sure to specify environment variables' values in your <code>.yml</code> file without double quotes (<code>"</code>). </p>
<p>This prevents unexpected errors when watchtower starts.</p>
<li><code>--notifications-level</code> (env. <code>WATCHTOWER_NOTIFICATIONS_LEVEL</code>): Controls the log level which is used for the notifications. If omitted, the default log level is <code>info</code>. Possible values are: <code>panic</code>, <code>fatal</code>, <code>error</code>, <code>warn</code>, <code>info</code> or <code>debug</code>.</li>
<p>To receive notifications by email, the following command-line options, or their corresponding environment variables, can be set:</p>
<ul>
<li><code>--notification-email-from</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_FROM</code>): The e-mail address from which notifications will be sent.</li>
<li><code>--notification-email-to</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_TO</code>): The e-mail address to which notifications will be sent.</li>
<li><code>--notification-email-server</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_SERVER</code>): The SMTP server to send e-mails through.</li>
<li><code>--notification-email-server-tls-skip-verify</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_SERVER_TLS_SKIP_VERIFY</code>): Do not verify the TLS certificate of the mail server. This should be used only for testing.</li>
<li><code>--notification-email-server-port</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT</code>): The port used to connect to the SMTP server to send e-mails through. Defaults to <code>25</code>.</li>
<li><code>--notification-email-server-user</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER</code>): The username to authenticate with the SMTP server with.</li>
<li><code>--notification-email-server-password</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD</code>): The password to authenticate with the SMTP server with.</li>
<li><code>--notification-email-delay</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_DELAY</code>): Delay before sending notifications expressed in seconds.</li>
<li><code>--notification-email-subjecttag</code> (env. <code>WATCHTOWER_NOTIFICATION_EMAIL_SUBJECTTAG</code>): Prefix to include in the subject tag. Useful when running multiple watchtowers.</li>
<p>If watchtower is monitoring the same Docker daemon under which the watchtower container itself is running (i.e. if you volume-mounted <em>/var/run/docker.sock</em> into the watchtower container) then it has the ability to update itself. If a new version of the <em>containrrr/watchtower</em> image is pushed to the Docker Hub, your watchtower will pull down the new image and restart itself automatically.</p>
<p>To receive notifications in Slack, add <code>slack</code> to the <code>--notifications</code> option or the <code>WATCHTOWER_NOTIFICATIONS</code> environment variable.</p>
<p>Additionally, you should set the Slack webhook URL using the <code>--notification-slack-hook-url</code> option or the <code>WATCHTOWER_NOTIFICATION_SLACK_HOOK_URL</code> environment variable.</p>
<p>By default, watchtower will send messages under the name <code>watchtower</code>, you can customize this string through the <code>--notification-slack-identifier</code> option or the <code>WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER</code> environment variable.</p>
<p>Other, optional, variables include:</p>
<ul>
<li><code>--notification-slack-channel</code> (env. <code>WATCHTOWER_NOTIFICATION_SLACK_CHANNEL</code>): A string which overrides the webhook's default channel. Example: #my-custom-channel.</li>
<li><code>--notification-slack-icon-emoji</code> (env. <code>WATCHTOWER_NOTIFICATION_SLACK_ICON_EMOJI</code>): An <ahref="https://www.webpagefx.com/tools/emoji-cheat-sheet/">emoji code</a> string to use in place of the default icon.</li>
<li><code>--notification-slack-icon-url</code> (env. <code>WATCHTOWER_NOTIFICATION_SLACK_ICON_URL</code>): An icon image URL string to use in place of the default icon.</li>
<p>To receive notifications in MSTeams channel, add <code>msteams</code> to the <code>--notifications</code> option or the <code>WATCHTOWER_NOTIFICATIONS</code> environment variable.</p>
<p>Additionally, you should set the MSTeams webhook URL using the <code>--notification-msteams-hook</code> option or the <code>WATCHTOWER_NOTIFICATION_MSTEAMS_HOOK_URL</code> environment variable.</p>
<p>MSTeams notifier could send keys/values filled by <code>log.WithField</code> or <code>log.WithFields</code> as MSTeams message facts. To enable this feature add <code>--notification-msteams-data</code> flag or set <code>WATCHTOWER_NOTIFICATION_MSTEAMS_USE_LOG_DATA=true</code> environment variable.</p>
