Fix for SQS Sensor when configured credentials are 'None'

[kylestewart]

Purpose

We are using an IAM Role on the node running StackStorm and despite the documentation saying None can be specified for the aws_access_key_id and aws_secret_access_key, we were not able to get this to work. Upon registering the sensor we would see this traceback in our logs:

2021-05-19 19:40:27,714 WARNING [-] Sensor "AWSSQSSensor" run method raised an exception: An error occurred (InvalidClientTokenId) when calling the GetCallerIdentity operation: The security token included in the request is invalid..
Traceback (most recent call last):
File "/opt/stackstorm/st2/lib/python3.6/site-packages/st2reactor/container/sensor_wrapper.py", line 240, in run
self._sensor_instance.run()
File "/opt/stackstorm/st2/lib/python3.6/site-packages/st2reactor/sensor/base.py", line 122, in run
self.poll()
File "/opt/stackstorm/packs/aws/sensors/sqs_sensor.py", line 69, in poll
self._may_setup_sqs()
File "/opt/stackstorm/packs/aws/sensors/sqs_sensor.py", line 131, in _may_setup_sqs
self._setup_session()
File "/opt/stackstorm/packs/aws/sensors/sqs_sensor.py", line 179, in _setup_session
self.account_id = session.client('sts').get_caller_identity().get('Account')
File "/opt/stackstorm/virtualenvs/aws/lib/python3.6/site-packages/botocore/client.py", line 251, in _api_call
return self._make_api_call(operation_name, kwargs)
File "/opt/stackstorm/virtualenvs/aws/lib/python3.6/site-packages/botocore/client.py", line 537, in _make_api_call
raise ClientError(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (InvalidClientTokenId) when calling the GetCallerIdentity operation: The security token included in the request is invalid.

The sensor would then shut down and our messages would not get handled.

Approach

Adding a simple IF statement to help translate the string value of 'None' in the config to the null Python object None resolved the issue for us.

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✅ kylestewart
❌ Kyle Stewart

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