Execution order of pytest_runtestloop hook in the controller and worker nodes.

[sashko1988]

I need to share some data between the controller and worker nodes.
That data is created on the controller node, then saved to a file and shared between workers.
Nodes (controller and worker) do that during pytest_runtestloop hook.

Sometimes, when I set a high number of workers >= 20, some of the workers attempt to open the file before the controller node has created it.

Code snippet:

    @pytest.hookimpl(wrapper=True, tryfirst=True)
    def pytest_runtestloop(self, session):
        if xdist.is_xdist_controller(session):
            create_file()
        else:
            process_file()
        return (yield)

I use file locks to prevent race conditions in create_file() and process_file(). However, it is still designed around the assumption that the controller is the first to execute pytest_runtestloop.

Also, does xdist have a built-in mechanism to share data between nodes when a worker node has already been set up?
UPD I just saw this - #1213 (comment), so I used the only mechanism.

But the question about execution order remains.