InvalidAccessKeyId - mocking no longer works

Versions

• boto==2.49.0
• boto3==1.9.225
• botocore==1.12.225
• moto==1.3.13

This issue has been raised many times before it appears, however after reading through all the reports and changing versions up and down to no avail, I’ve decided to raise another issue. When I try to mock out AWS using moto, I am getting the following error:

(InvalidAccessKeyId) when calling the GetObject operation: The AWS Access Key Id you provided does not exist in our records.

I’ve tried setting fake credentials using os.environ, I’ve tried deleting my credentials from the cli configuration, I’ve tried downgrading botocore/boto3 versions, I’ve tried re-arranging imports. None of this has helped unfortunately. Hopefully I’m missing something, but if not, there is something wrong.

The code

@mock_sqs
@mock_s3
@mock_sns
def test_bad_data(self):
    ...
    response = function.lambda_handler(
        None,
        None
    )
    ...

Calling the lambda_handler from the test is what lead us to the error:

def lambda_handler(event, context):
    ...
    try:
        ...
        s3 = boto3.resource('s3', region_name="eu-west-2")
        sqs = boto3.client('sqs', region_name="eu-west-2")
        lambda_client = boto3.client('lambda', region_name="eu-west-2")
        ...
        input_file = read_from_s3(s3, config['bucket_name'], config['file_name'])
        ...

It is where the read_from_s3 function is called that it tells me I have invalid credentials, which is the first instance of connecting to AWS. For reference, here is the read_from_s3 function:

def read_from_s3(s3, bucket_name, file_name):
    # Read from S3
    object = s3.Object(bucket_name, file_name)
    input_file = object.get()['Body'].read()

    return input_file

What was expected to happen Successfully mock AWS in tests.

What actually happens InvalidAccessKeyId error, suggesting that moto mocking isn’t working.

If I’ve missed any important details please let me know so I can update.