Psycopg2Instrumentor doesn't work for cursors with non-default cursor_factory

[r-daysleeper]

opentelemetry-python-contrib/instrumentation/opentelemetry-instrumentation-psycopg2/src/opentelemetry/instrumentation/psycopg2/__init__.py

Lines 126 to 141 in 2ee2cf3

	class DatabaseApiIntegration(dbapi.DatabaseApiIntegration):
	def wrapped_connection(
	self,
	connect_method: typing.Callable[..., typing.Any],
	args: typing.Tuple[typing.Any, typing.Any],
	kwargs: typing.Dict[typing.Any, typing.Any],
	):
	"""Add object proxy to connection object."""
	base_cursor_factory = kwargs.pop("cursor_factory", None)
	new_factory_kwargs = {"db_api": self}
	if base_cursor_factory:
	new_factory_kwargs["base_factory"] = base_cursor_factory
	kwargs["cursor_factory"] = _new_cursor_factory(**new_factory_kwargs)
	connection = connect_method(*args, **kwargs)
	self.get_connection_attributes(connection)
	return connection

When wrapping the connection, the default cursor_factory is set for the connection, but the connection is returned as is rather than a proxy. Therefore, when a cursor is created with the connection_factory argument passed, the instrumentation does not happen.

Steps to reproduce
Set up the Psycopg2Instrumentor, create a cursor passing the cursor_factory argument, and run a query.

What is the expected behavior?
Spans produced/exported

What is the actual behavior?
No spans produced/exported

[github-actions]

This issue was marked stale due to lack of activity. It will be closed in 30 days.

[raguramgopi]

Is there a fix for this issue?

[AlexanderLW]

I am also facing this same issue but for creating a cursor using the RealDictCursos cursor factory.
cur = client.cursor(cursor_factory=psycopg2.extras.RealDictCursor)

No tracing is being submitted, but when I turn this off for the whole app (and comment out the breaking code now that it's getting tuples) I start seeing my traces appear.

Is there any fix for this or can anyone comment on this issue?

[raguramgopi]

@AlexanderLW, @srikanthccv I have gone through the code. We have to add the {'cursor_factory': psycopg2.extras.RealDictCursor} in connection params.

you must have had conn_params in your code like below.
self._conn_parms = {'host': host, 'post': port, 'username': username, 'password': password, 'cursor_factory': psycopg2.extras.RealDictCursor}

It will fix the issue.

For more details, understand wrapped_connection method in python3.9/site-packages/opentelemetry/instrumentation/psycopg2/init.py

[AlexanderLW]

Thanks @RaguRamG !

For anyone else that runs into this, I moved the cursor_factory to the connection, and then I had to remove the cursor_factory from any and all cursor declarations. Doing that allowed my traces to appear as I would expect.