boto3 uses incorrect EMR service endpoint

Here is the error thrown when attempting to use any boto3.client('emr') command in us-west-2:

Traceback (most recent call last):
  File...botocore/httpsession.py", line 287, in send
    raise ConnectTimeoutError(endpoint_url=request.url, error=e)
botocore.exceptions.ConnectTimeoutError: Connect timeout on endpoint URL: "https://us-west-2.elasticmapreduce.amazonaws.com/"

I was trying to add a step to an EMR in us-west-2 from another EMR in the same region when I began running into the botocore.exceptions.ConnectTimeoutError.

The service endpoint listed by the error message is https://us-west-2.elasticmapreduce.amazonaws.com/

AWS docs say it should be: elasticmapreduce.us-west-2.amazonaws.com doc

Here are the contents of my virtual environment:

boto3==1.12.20
botocore==1.15.20
docutils==0.15.2
fsspec==0.6.2
jmespath==0.9.5
python-dateutil==2.8.1
s3fs==0.4.0
s3transfer==0.3.3
six==1.14.0
urllib3==1.25.8

[swetashre]

@zking1219 - Thank for your post. Can you please provide me the exact code you are running ? It would be helpful if you could provide me full debug logs. You can enable log by adding boto3.set_stream_logger('') to your code.

[bitbier]

In case anyone stumbles upon this, it’s actually a configuration issue in Botocore (https://github.com/boto/botocore/issues/2376). Basically, if you want to use private VPC endpoints, you’ll need to pass in the endpoint_url to use it.

>>> import boto3
>>> session = boto3.Session()
>>> endpoints = session._session.get_component("endpoint_resolver")
>>> endpoints.construct_endpoint("elasticmapreduce", "us-west-2")
OrderedDict([('partition', 'aws'), ('endpointName', 'us-west-2'), ('protocols', ['https']), ('sslCommonName', 'us-west-2.elasticmapreduce.amazonaws.com'), ('hostname', 'elasticmapreduce.us-west-2.amazonaws.com'), ('signatureVersions', ['v4']), ('dnsSuffix', 'amazonaws.com')])

The sslCommonName has the inverted region and service name.

However, it’s correct for us-east-1:

>>> endpoints.construct_endpoint("elasticmapreduce", "us-east-1")
OrderedDict([('sslCommonName', 'elasticmapreduce.us-east-1.amazonaws.com'), ('partition', 'aws'), ('endpointName', 'us-east-1'), ('protocols', ['https']), ('hostname', 'elasticmapreduce.us-east-1.amazonaws.com'), ('signatureVersions', ['v4']), ('dnsSuffix', 'amazonaws.com')])

See: https://github.com/boto/botocore/blob/develop/botocore/data/endpoints.json#L2605-L2607