DM-26526: Can't run RawIngestTask with processes != 1 #294
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TallJimbo
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Sep 9, 2020
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Looks great!
I don't think I had any line comments. The fact that multiprocessing can't handle local callables is not surprising in retrospect, but it still makes me sad about how really fundamental functional programming elements are sort of only halfway supported in Python. But I've got no complaints about your workaround.
kfindeisen
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Multiprocessing does not work with local callables (because they can't be pickled), and well-performing frameworks like imap_unordered require unary callables. I used private wrapper methods to satisfy both requirements.
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This PR fixes two issues that were preventing the use of the
processesargument withRawIngestTaskandDefineVisitsTask: support for pickling task instances, and use of local (i.e., non-picklable) callables to implement processing steps.Unfortunately, this functionality cannot be checked through unit tests, because calling either
RawIngestTask.runorDefineVisitsTask.runrequires aCameraobject, which the hypothetical "DummyCam" doesn't have.