Feature: add site-wide handle_info callbacks

[ddink]

What will it allow you to do that you can't do today?

These changes will make it possible to add site-wide handle_info callbacks that will be applied to each Beacon page. There is also a complementary pull-request to beacon_live_admin that adds support for administering the CRUD of these site-wide callbacks.

Why do you need this feature and how will it benefit other users?

This feature will give users the ability to handle messages sent by Kernel.send/2 . Commonly, this can be used to do things like put flash messages, navigate to another LiveView, work with streams, etc. in response to messages sent by the application.

Are there any drawbacks to this feature?

• This feature is not designed to create page-specific handle_info callbacks—just site-wide callbacks that are useable on all of a site’s pages. I’m happy to add a page-specific handle_info callbacks feature at a later point, though.

• Changes to handle_info callbacks through the admin require a recompile before they are useable. They are not immediately useable upon a refresh of a Beacon page the way that an update to a Beacon page is immediately viewable.

[leandrocp]

Hey @ddink great work! Sorry for the delay, things piled up with ElixirConf. In overall it's looking good, just left a few comments that we need to address before merging it. Thanks!

[leandrocp]

Hey @ddink one last small change and then we're done with this PR. I'm gonna check the live_admin PR now. Thanks!

[leandrocp]

Hey @ddink that looks good, great contribution! I'll merge into main and release right after v0.1 since that version is frozen for new features, but that should happen soon. Thanks!

[leandrocp]

Thanks @ddink !