Launching ipdb (or pdb) in steps

Hello,

Is it possible to use ipdb (or pdb) inside steps? On my code, it hangs without showing anything.

I have something like:

class MyTrain(FlowSpec):

    @step
    def start(self):
        print("Start ipdb")
        __import__("pdb").set_trace()

        self.next(self.load_dataset)

And the final output is:

$ python train.py run
...
2020-01-08 16:45:59.297 [1578512759283042/start/1 (pid 22301)] Task is starting.
2020-01-08 16:46:00.773 [1578512759283042/start/1 (pid 22301)] > /home/user521/metaflow-pytorch-example/train.py(97)start()

Thanks

[yariv]

I use vim and debug python from the command line using ipdb so these instructions won’t work for me, unfortunately. If I could submit a feature request it would be to make it so that --max-workers=1 prevents forking child processes and serializes the execution in the main process.

[ifokeev]

use https://pypi.org/project/web-pdb/, it works fine