[SP-333] Assume Role Support

[waltaro]

SP-333

Changes

• Add CONNECTION_DATA_ROLE_KEY constant
• Add CONNECTION_DATA_FUNCTION_KEY constant
• Add CONNECTION_DATA_TENANT_KEY constant
• Add AWS_SERVICE_LAMBDA constant
• Add AWS_SERVICE_S3 constant
• Add sts client to AWSLambdaDataSource
• Add __assume_role(...) method
  • Returns credentials from response
• Add __get_aws_client(...) method
• Add __refresh_aws_clients_if_expired(...) method
• Reformat code

Notes

Assume Role

The following clients will now be instantiated with AWS credentials:

• Lambda
• S3

If the clients are nearing their expiration date (~5 minutes), we will re-assume the role for a fresh set of credentials and update the clients accordingly.

AWS Lambda Connection String

Now expects role=arn:aws:iam:{accountId}:role/{roleName}