Event Hook Teardown¶

on_teardown() is called once when the server shuts down and the hook is being unregistered. Use it to flush state to disk, close open connections, or perform any final cleanup:

import json


async def on_teardown(self) -> None:
    summary_path = self.root_directory / "last_session_summary.json"
    summary = {
        str(event_type): count
        for event_type, count in self.environment.counts.items()
    }
    with summary_path.open("w") as f:
        json.dump(summary, f, indent=2)
    self.logger.info("Session summary written to '{}'.", summary_path)

self.root_directory is a pathlib.Path pointing to the directory that contains your event hook's source files. Use it exactly like self.root_directory in plugins.

Signalling teardown failures¶

Raise EventHookTeardownError from on_teardown() to signal that cleanup failed. This aborts unloading: the event hook's handlers are not deregistered from the events service, and the registry surfaces the failure as an EventHookTeardownError (from consortium.server.exceptions.consortium_exceptions.event_hooks_consortium_exceptions) carrying your message and any structured detail you provide.

from consortium.framework.signal_exceptions.event_hooks_signal_exceptions import (
    EventHookTeardownError,
)


async def on_teardown(self) -> None:
    try:
        summary_path = self.root_directory / "last_session_summary.json"
        with summary_path.open("w") as f:
            json.dump(self.environment.counts, f, indent=2)
    except OSError as exc:
        raise EventHookTeardownError(
            message=f"Failed to write session summary: {exc}",
            detail={"exception_type": type(exc).__name__},
        ) from exc

As with on_setup() and on_triggered(), do not catch and log teardown failures internally, and do not let a bare exception escape unremarked: raise EventHookTeardownError so the failure is reported with the same structured code/message/detail shape as every other framework error.

Continue to Event Hook Conventions for guidance on structuring event hook code.