How to add lambda invoke role in custom authorizer of api gateway using serverless framework - aws-api-gateway

Question

I would like to add Lambda invoke role in custom authorizer for an api gateway using serverless framework.
events:
- http:
path: controls
method: GET
cors: ${self:custom.lambdaCORS}
authorizer:
arn: arn:aws:lambda:us-east-1:XYZ:function:SLS-XYZ
managedExternally: true
identitySource: method.request.header.x-api-key
resultTtlInSeconds: 0
type: request
Can someone help me in finding the property under authorizer to add "Lambda invoke role". I was able to do it manually from aws console. I am trying to access authorizer defined in other region. It seems API gateway needs a permission to invoke lambda authorizer in another region.

Answer 1

So the solution I was able to come up with was to add a specific permission to the generate API Gateway Cloudformation template.
The AWS docs outline what the Cloudformation template should look like to add a permission for API Gateway to access a lambda:
https://aws.amazon.com/premiumsupport/knowledge-center/api-gateway-rest-api-lambda-integrations/#To_add_Lambda_invoke_permission_to_a_REST_API_with_a_Lambda_integration_using_a_CloudFormation_template
So if you adapt that and add this block to the bottom of your serverless.yaml you should be able to access the Authorizer referenced by the FunctionName field!
resources:
Resources:
InvokeAuthorizerPermission:
Type: AWS::Lambda::Permission
Properties:
Action: "lambda:InvokeFunction"
FunctionName: ARN_OF_AUTHORIZER
Principal: "apigateway.amazonaws.com"
SourceArn: "arn:aws:execute-api:${aws:region}:${aws:accountId}:*/*/*/*"
Hope this helps another lost soul and I smashed my head up against this for a good long while!