SignatureDoesNotMatch when calling PutObject

[sleibrock]

Hi, I'm currently using django-storages in conjunction with Amazon S3 to upload images from a Django application running on Heroku. I added the setting vars as per the docpage here, which leads to an error saying to use AWS4-HMAC-SHA256 when trying to do python manage.py collectstatic.

Using sdeleeuw's instructions here changes the request to use v4 authentication, but now it's giving me a SignatureDoesNotMatch error. However, I can perfectly upload files with boto3 with my current credentials and with v4 authentication in a script like this:

from sys import argv
import boto3
from botocore.client import Config

def main(fname):
    s3 = boto3.client('s3', 'us-west-2', config=Config(s3={"addressing_style":" path"}, signature_version="s3v4"))
    s3.upload_file(fname, "my-bucket", fname)

if __name__ == "__main__":
    if len(argv) > 1:
        for f in argv[1:]:
            main(f)

Here is my output log which doesn't really tell much of a story

  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\boto3\s3\inject.py", line 509, in object_upload_fileobj
    ExtraArgs=ExtraArgs, Callback=Callback, Config=Config)
  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\boto3\s3\inject.py", line 427, in upload_fileobj
    return future.result()
  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\s3transfer\futures.py", line 73, in result
    return self._coordinator.result()
  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\s3transfer\futures.py", line 233, in result
    raise self._exception
  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\s3transfer\tasks.py", line 126, in __call__
    return self._execute_main(kwargs)
  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\s3transfer\tasks.py", line 150, in _execute_main
    return_value = self._main(**kwargs)
  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\s3transfer\upload.py", line 679, in _main
    client.put_object(Bucket=bucket, Key=key, Body=body, **extra_args)
  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\botocore\client.py", line 253, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "C:\Users\sleibrock\AppData\Local\Programs\Python\Python35\lib\site-packages\botocore\client.py", line 543, in _make_api_call
    raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (SignatureDoesNotMatch) when calling the PutObject operation: The request signature we calculated does not match the signature you provided. Check your key and signing method.

Has anyone run into this problem with Heroku/S3/Django before and have a solution? Are there any settings that can be changed to fix this issue? I can post more info as needed, thank you.

[ghost]

If you solved it, would you care to share how?

[sleibrock]

It's stupidity on my part. In my Django project I had a blank file to keep a folder in my Git tracker to run the project. You can't generate a signature for a blank file that has no bytes written to it, so I wrote one character to the file, saved it and it worked without an issue.