Not able to upload a compressed S3 file using close()/without context manager

[jbarragan-bridge]

Problem description

• What are you trying to achieve?

We are using smart_open to compress and upload files to s3 without a context manager:
e.g.

hook = S3Hook()
s3_params = {
    'client': hook.get_session().client('s3'),
}
f = smart_open.open('s3://bucket/file.gz', 'w', transport_params=s3_params)
f.write('Some content')
f.close()

• What is the expected result?
  The expected result (and the result previous version 7.0.0) is to have the MultipartWriter.close() been called to perform a S3 complete multipart upload and see the file uploaded into s3

• What are you seeing instead?
  The file is not uploaded and MultipartWriter.close() is not called.

Steps/code to reproduce the problem

Adding the following tests to test_s3.py (class MultipartWriterTest) shows our problem:

    def test_write_gz_using_context_manager(self):
        """Does s3 multipart upload create a compressed file using context manager?"""
        contents = b'get ready for a surprise'
        with smart_open.open(
                f's3://{BUCKET_NAME}/{WRITE_KEY_NAME}.gz',
                mode="wb",
                transport_params={
                    "multipart_upload": True,
                    "min_part_size": 10,
                }
        ) as fout:
            fout.write(contents)

        with smart_open.open(f's3://{BUCKET_NAME}/{WRITE_KEY_NAME}.gz', 'rb') as fin:
            actual = fin.read()

        assert actual == contents

    def test_write_gz_not_using_context_manager(self):
        """Does s3 multipart upload create a compressed file not using context manager but close()?"""
        contents = b'get ready for a surprise'
        fout = smart_open.open(
            f's3://{BUCKET_NAME}/{WRITE_KEY_NAME}.gz',
            mode="wb",
            transport_params={
                "multipart_upload": True,
                "min_part_size": 10,
            }
        )
        fout.write(contents)
        fout.close()

        with smart_open.open(f's3://{BUCKET_NAME}/{WRITE_KEY_NAME}.gz', 'rb') as fin:
            actual = fin.read()

        assert actual == contents

Versions

This looks to be affecting from v7.0.0 to current version

Please provide the output of:

Linux-6.5.7-arch1-1-x86_64-with-glibc2.38
Python 3.11.5 (main, Sep  2 2023, 14:16:33) [GCC 13.2.1 20230801]
smart_open 7.0.4

Probably related to this PR #786 here:

https://github.com/piskvorky/smart_open/pull/786/files#diff-ba9d790d5607c344a97e86f15b3706586deb24d52d52cdf70b9776e3f3412b69L103

Recommendation

Probably closing both, outer and inner in FileLikeProxy will help:

class FileLikeProxy(wrapt.ObjectProxy):
    __inner = ...  # initialized before wrapt disallows __setattr__ on certain objects
...
    def __next__(self):
        return self.__wrapped__.__next__()

    def close(self):
        try:
            self.__wrapped__.close()
        finally:
            self.__inner.close()

I can open a PR if that helps.

Thanks for reading!!

Checklist

Before you create the issue, please make sure you have:

• [ x ] Described the problem clearly
• [ x ] Provided a minimal reproducible example, including any required data
• [ x ] Provided the version numbers of the relevant software

[ddelange]

Sounds like indeed this case was not covered. Can you open a PR?

[jbarragan-bridge]

Thanks @ddelange , I created PR #838 to address the issue

I am NOT sure if that is a good solution; please let me know if I should consider another approach. Thanks for all the help!!

[ddelange]

@jbarragan-bridge @mpenkov this issue can be closed with 7.0.5 released

[jbarragan-bridge]

Yes, thank you!!