AttributeError: 'mod_wsgi.Input' object has no attribute 'tell'

[sakshigupta3]

I'm running the below versions of httpd, mod_wsgi and latest google-cloud-storage code

• httpd-2.4.41-12.fc31.x86_64
• python3-mod_wsgi-4.6.6-2.fc31.x86_64
• python3.7

I'm getting the below traceback sometimes, the issue is intermittent and that's why more confusing ( Like once in an hour ). We upgraded from python2.7 to python3.7, could this be a dependency issue ? Is so, why is it intermittent ?

[2020-03-19 07:23:01,337] [ERROR] GCPStorage: PutRequest: stest.2020-03-19/DynamicPolicyRouteChangeTest.py-stest131.sjc-16045647-403435829.log.gz. Unexpected error: (<class 'AttributeError'>) 'mod_wsgi.
Input' object has no attribute 'tell'
[2020-03-19 07:23:01,340] [ERROR] Traceback (most recent call last):
File "/usr/lib/python3.7/site-packages/LogLake/Server.py", line 477, in handlePutRequest
requestBody, requestHeaders )
File "/usr/lib/python3.7/site-packages/LogLake/Storage.py", line 79, in putObject
self.bucketName( bucketName ), objectName, content, headers )
File "/usr/lib/python3.7/site-packages/LogLake/GCPStorage.py", line 221, in doPutObject
size=fileSize, client=self.gcpStorageClient )
File "/usr/local/lib/python3.7/site-packages/google/cloud/storage/blob.py", line 1261, in upload_from_file
client, file_obj, content_type, size, num_retries, predefined_acl
File "/usr/local/lib/python3.7/site-packages/google/cloud/storage/blob.py", line 1171, in _do_upload
client, stream, content_type, size, num_retries, predefined_acl
File "/usr/local/lib/python3.7/site-packages/google/cloud/storage/blob.py", line 1114, in _do_resumable_upload
predefined_acl=predefined_acl,
File "/usr/local/lib/python3.7/site-packages/google/cloud/storage/blob.py", line 1063, in _initiate_resumable_upload
stream_final=False,
File "/usr/local/lib/python3.7/site-packages/google/resumable_media/requests/upload.py", line 343, in initiate
stream_final=stream_final,
File "/usr/local/lib/python3.7/site-packages/google/resumable_media/_upload.py", line 414, in _prepare_initiate_request
if stream.tell() != 0:
AttributeError: 'mod_wsgi.Input' object has no attribute 'tell'

[sakshigupta3]

I raised this issue in mod_wsgi repo and GrahamDumpleton/mod_wsgi#545 the fix helped. FYI: We were running absolutely fine with python2.7.

[busunkim96]

@tseaver @crwilcox Could you take a look?

[IlyaFaer]

@busunkim96, @crwilcox, I've taken a look, it seems to be not a Resumable Media issue. upload() treats an uploaded object as a file-like instance, so it expects an uploaded object to support file methods, like tell(), seek(), etc.

The object caused the error is not a standard Python, nor Resumable Media object, it's a class from a third-party package, and it's not very file-like. It supports some of the file operations, but tell() and seek() are not among them, per package owner's comment they can break the expected behavior. Still, user can convert the data from this object into more file-like form and pass it into Res Media's upload().

Thus, there is just no straight way to pass data from the third-party package to Res Media, as both of them have some data requirements, which can't be ignored in any of them. But this can be solved with a data conversion in between them, so I assume the issue can be closed.