A little Flask webapp to pass messages from one channel to another. We use this to replicate the content of some internal discussion channels with our guest-accessible "friends of Balloon" channel.
Create an incoming webhook for the target channel.
# on some webservery-like unix box pip install -r requirements.txt export SLACK_WEBHOOK='YOUR_INCOMING_WEBHOOK_URL' python echo.py
This will start the webserver listening on port 3246.
Configure an outgoing webhook in your Slack integrations from the channel you
want replicated that points to
Now, when something is said in the replicated channel, you should see it echoed back in the target channel.
Deploying this properly is left as an exercise for the reader.