Slack Publisher Documentation implies support for Block Kit messages

[cch1]

The documentation for the Slack publisher states that the render-message function can return one more blocks per the Slack documentation for Block Kit. I have not been able to send blocks and a quick review of the code shows that the publisher only sends the :text JSON key while, per the Slack Block Kit documentation, block support requires the :blocks key. While the :text key supports markdown, it does not support Blocks.

[BrunoBonacci]

Hi @cch1,

you are correct, I guess the documentation is incorrect saying that you can customize the block.
Admittedly, I never used the Slack publisher, it was contributed as a PR.

Would you be interested in contributing the necessary changes as a PR?

I would say, in order to not break other users and make the change backward compatible, we need:

1. introduce a new customization function called :render-block which defaults to {:text message}
2. amend the doc of :render-message to make it clear that is an event -> message-string function
3. send Individual message/block rather than concatenating them into one in line 64
4. update the doc in ./doc/publishers/slack-publisher.md