I’ve created a library that allows you to get notified about PostgeSQL inserts, updates, and deletes as Phoenix PubSub messages in your Elixir app. You might find this useful, for example, when updating caches or sending notifications about record updates.
See the README for more details and examples:
Thank you for providing a more general and complete solution for pg_notify. The DX is good. Really like it.
This is really useful - well done and thanks for making this available to the community.
Can we use this in production?
As far as I know it’s been working stably for people. It has a pretty thorough test suite. So overall, it should be fine to use in production.
The method of database notifications that ecto_watch uses should scale quite a ways, but if you have a really large amount of activity or if you have big bursts, you should understand it’s performance characteristics (as with anything).
I have one PR that I hope to be merging soon to protect people from database trigger/function names being too long. Before that is merged, I’d suggest checking out this issue and using the label option if you experience a similar issue on startup.
is it possible to have brief overview of it works as diagram if otp used?
Not sure that I understand, but the structure that is used is pretty simple. If you add EctoWatch into your application, a Supervisor is created. For every EctoWatch watcher that you add, a GenServer is created which listens for messages from the database.
When the Supervisor is started, it runs these queries for each watcher:
CREATE OR REPLACE FUNCTION ...DROP TRIGGER IF EXISTS ...CREATE TRIGGER ...The trigger calls the function which sends a notification to your application/the watcher GenServer.
And then each GenServer does a Phoenix.PubSub.broadcast for each message from the database so that you can get application updates (as described in the README)
If that’s not clear I’m happy to answer other questions.
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