This allows the user to specify arguments that will be passed to each execution of a wal plugin trigger. The CLI test was updated to check this end to end.
Closes#25655
This updates the WAL so that it can have new file notifiers added that will get updated when the wal flushes. The processing engine now implements the WALNotifier trait.
I've updated the CLI test for creating a trigger to run and end-to-end test that defines a plugin, creates a trigger, writes data into the database, triggering the plugin, which writes summary statistics back into the database in a different table. The test queries the destination table to confirm that the plugin worked.
* feat: Update WAL plugin for new structure
This ended up being a very large change set. In order to get around circular dependencies, the processing engine had to be moved into its own crate, which I think is ultimately much cleaner.
Unfortunately, this required changing a ton of things. There's more testing and things to add on to this, but I think it's important to get this through and build on it.
Importantly, the processing engine no longer resides inside the write buffer. Instead, it is attached to the HTTP server. It is now able to take a query executor, write buffer, and WAL so that the full range of functionality of the server can be exposed to the plugin API.
There are a bunch of system-py feature flags littered everywhere, which I'm hoping we can remove soon.
* refactor: PR feedback
Paul Dix
Trevor Hilton