How do you use Boto3 download_file with AWS KMS?

Question

I have very simple script that downloads a file from a bucket. The file is leveraging KMS encrypted keys, my policies and roles are setup correctly but I still get an error.

Code

#!/usr/bin/env python
import boto3
s3_client = boto3.client('s3')
s3_client.download_file('testtesttest', 'test.txt', '/tmp/test.txt')

Error

Traceback (most recent call last):
  File "./getfile.py", line 4, in <module>
s3_client.download_file('testtesttest', 'test.txt', '/tmp/test.txt')
File "/usr/local/lib/python2.7/dist-packages/boto3/s3/inject.py", line 91, in download_file
extra_args=ExtraArgs, callback=Callback)
File "/usr/local/lib/python2.7/dist-packages/boto3/s3/transfer.py", line 659, in download_file
extra_args, callback)
File "/usr/local/lib/python2.7/dist-packages/boto3/s3/transfer.py", line 674, in _download_file
self._get_object(bucket, key, filename, extra_args, callback)
File "/usr/local/lib/python2.7/dist-packages/boto3/s3/transfer.py", line 698, in _get_object
extra_args, callback)
File "/usr/local/lib/python2.7/dist-packages/boto3/s3/transfer.py", line 712, in _do_get_object
**extra_args)
File "/usr/local/lib/python2.7/dist-packages/botocore/client.py", line 301, in _api_call
return self._make_api_call(operation_name, kwargs)
File "/usr/local/lib/python2.7/dist-packages/botocore/client.py", line 386, in _make_api_call
raise ClientError(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (InvalidArgument) when calling the GetObject operation: Requests specifying Server Side Encryption with AWS KMS managed keys require AWS Signature Version 4.

Answer 1

Figured it out

Code

#!/usr/bin/env python
import boto3
from botocore.client import Config
s3_client = boto3.client('s3', config=Config(signature_version='s3v4'))
s3_client.download_file('testtesttest', 'test.txt', '/tmp/test.txt')