This ended up being a couple things rolled into one. In order to add a query API to the Python plugin, I had to pull the QueryExecutor trait out of server into a place so that the python crate could use it.
This implements the query API, but also fixes up the WAL plugin test CLI a bit. I've added a test in the CLI section so that it shows end-to-end operation of the WAL plugin test API and exercise of the entire Plugin API.
Closes#25757
* feat: Implement WAL plugin test API
This implements the WAL plugin test API. It also introduces a new API for the Python plugins to be called, get their data, and call back into the database server.
There are some things that I'll want to address in follow on work:
* CLI tests, but will wait on #25737 to land for a refactor of the CLI here
* Would be better to hook the Python logging to call back into the plugin return state like here: https://pyo3.rs/v0.23.3/ecosystem/logging.html#the-python-to-rust-direction
* We should only load the LineBuilder interface once in a module, rather than on every execution of a WAL plugin
* More tests all around
But I want to get this in so that the actual plugin and trigger system can get udated to build around this model.
* refactor: PR feedback
* Move processing engine invocation to a seperate tokio task.
* Support writing back line protocol from python via insert_line_protocol().
* Update structs to work with bincode.
Paul Dix
Jackson Newhouse