docker-slack-message

Very simple tool to send Slack messages. Built into a docker image

Mentioning users who aren't in the channel

When the message tags a Slack user (<@U...>) who is not a member of the target channel, the mention is otherwise silent. Set SLACK_MENTION_MEMBERSHIP_MODE to act on every user tagged in the message:

• none (default) — do nothing, current behavior.
• invite — invite the tagged users to the channel. Requires the channels:write.invites (public) or groups:write (private) scope, and the bot must already be a member of the channel (otherwise the invite fails with not_in_channel).
• notify — DM each tagged user a link to the channel. Requires im:write and chat:write. The DM is always sent; membership is not checked first.

Failures here are logged but never fail the run — posting the message is the primary success.

Testing commands

Requires a bot token (xoxb-...). See Slack docs to create one: https://api.slack.com/quickstart. Run the test.sh script.