Fix a bug that too many file are being watched when using hot-reloading

[haixuanTao]

Currently there is an issue that the hot-reloading file watcher does not automatically notify the OS to stop watching files when the dataflow stop.

The error was as follows: https://stackoverflow.com/questions/53930305/nodemon-error-system-limit-for-number-of-file-watchers-reached

[phil-opp]

I'm not sure whether I understand this issue. The watcher doesn't unwatch the files automatically when it's dropped?

Also, the watching seems to happen in our CLI process, which should exit when a dataflow finishes. Doesn't the OS clean up the file watchers when the corresponding process exits?

[haixuanTao]

Ok, I can't reproduce the error at the moment. Can we leave this open, and if I ever encounter the error again, i'll try to see if this fixes it. :)

Thanks for double checking

[haixuanTao]

Ok, so i double checked the number of files being watched and indeed. Inotify closes it normally without having to unsubscribe it.

If other people face the same issue:

OS file watch limit reached. about ["/home/dora/workspace/simulate/team_code/dora-drives/operators/obstacle_location_op.py"]

What fixed it for me was: https://stackoverflow.com/questions/53930305/nodemon-error-system-limit-for-number-of-file-watchers-reached