Initial plugin design

[simonw]

This will use the new track_events() plugin hook to write events to a database.

Can't release an alpha of this until Datasette 1.0a8 is out.

• track_event() mechanism for analytics simonw/datasette#2240

[simonw]

Got the most basic version working:

[simonw]

Surprising test failure:

    def get_database(self, name=None, route=None):
        if route is not None:
            matches = [db for db in self.databases.values() if db.route == route]
            if not matches:
                raise KeyError
            return matches[0]
        if name is None:
            name = [key for key in self.databases.keys()][0]
>       return self.databases[name]
E       KeyError: '_internal'

Works fine on my laptop!

[simonw]

Relevant code in the test:

datasette-events-db/tests/test_events_db.py

Lines 17 to 24 in 0326df3

	datasette = Datasette(
	memory=True,
	config=config,
	)
	db = datasette.add_memory_database("demo")
	await datasette.invoke_startup()
	# Drop table if it exists
	await db.execute_write("drop table if exists new_table")

Could it be that the plugin hook is executing and trying to create a table in _internal before the Datasette code that populates _internal has run?

[simonw]

That looks likely:

https://github.com/simonw/datasette/blob/569aacd39bcc5529b2f463c89c616e3ada21c560/datasette/app.py#L475-L479

    async def _refresh_schemas(self):
        internal_db = self.get_internal_database()
        if not self.internal_db_created:
            await init_internal_db(internal_db)
            self.internal_db_created = True

And refresh_schemas() is called by the various view functions. So if a view hasn't been processed yet the database won't exist!

[simonw]

Actually no it isn't that at all - you need to call datasette.get_internal_database() instead of get_database("_internal").

The only reason it worked on my local machine is that I had installed the https://github.com/datasette/datasette-visible-internal-db plugin as a debugging aid!

[simonw]

Released: https://pypi.org/project/datasette-events-db/