Fix avoidable S3 race condition (#693) #735
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smart_open/s3.py
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| if 'Error' in err.response and err.response['Error'].get('Code') == '404': | ||
| logger.warning( | ||
| "Encountered '404 Not Found' error for key #%i", | ||
| key_no |
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Would it perhaps make sense to log the key, rather than the key_no? If anybody does care to see the log, I'm not sure the number would be as helpful in debugging a situation.
An argument could perhaps be made that it's not actually worthy of being logged as a warning. An end-user could read this as something being wrong or broken, when this is completely valid behavior that is to be expected from time to time.
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That is a very good point. If a 404 error occurs during iter_bucket, it is almost certainly not the users fault, but rather the fault of the internal list_keys function. I agree that logging the error would just be confusing to the user. I've removed the warning in my latest commit. Let me know what you think.
RachitSharma2001
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smart_open/s3.py
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| while True: | ||
| try: | ||
| (key, content) = result_iterator.__next__() | ||
| if True or key_no % 1000 == 0: |
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Any need for the True or bit?
edit: I realize that was there before. I wonder why 🤔
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I was also wondering this while I was looking at the code. I am not sure why it is there, I can remove it if its confirmed that it is not needed.
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Perhaps @mpenkov knows more about this.
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Thank you @RachitSharma2001 ! |
Motivation
Fixes #693
As proposed by @ronkorving, it may be common for the s3
iter_bucketfunction to encounter404 not founderrors due to the s3list bucketcommand sometimes returning recently deleted keys. So a workaround of this problem is to surpress 404 errors foriter_bucket, and instead log them as warnings for the user to assess.Tests
All existing tests related to
iter_bucketwithins3.pypass. I also added two new tests:test_iter_bucket_404andtest_iter_bucket_non_404. The first test simulates the scenario withiter_bucketfor a key throws a 404 error, and expects that error to be suppressed and for computation to carry on for the rest of the keys. The latter test simulates the scenario where a non 404 error occurs, in which case it should not be suppressed.