AWS api gateway custom authorizer: access context variable in mapping template

Question

I have implemented a custom authorization module in AWS API Gateway using python. Basically it might return something like this:

access = {
    "principalId": "yyyyyyyy",
    "policyDocument" : {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Action": "execute-api:Invoke",
                "Resource": [
                    "some-arn/*/GET/organisation"
                ],
                "Effect": "Allow"
            }
        ]
    },
    "context" : {
        "organization_id": "123"
    }
}

At the backend site i want to perform a GetItem on DynamoDb. The mapping template looks like this:

{   
    "TableName":"Organisation",
    "Key":{
        "id":{
            "S":"$context.authorizer.organization_id"
        }
    }
}

However, i am receiving an error, since the context variable seems to be empty:

Mon Jul 10 19:47:16 UTC 2017 : Endpoint request body after transformations: {   ""
    "TableName":"Organisation",
    "Key":{
        "id":{
            "S":""
        }
    }
}

Mon Jul 10 19:47:16 UTC 2017 : Endpoint response body before transformations: {"__type":"com.amazon.coral.service#SerializationException"}

Any suggestions, what i am doing wrong here?

Answer 1

After a lot of testing, I found out that the problem does only appear when testing using AWS console. This issue is also covered here . Hopefully AWS will solve this issue any soon.