Passing AWS region and account ID to swagger - amazon-web-services

Question

I am defining my API Gateway APIs using AWS SAM
ApiGatewayApi:
Type: AWS::Serverless::Api
Properties:
DefinitionUri: swagger.yml
StageName: prod
Variables:
Region: !Ref AWS::Region
AccountId: !Ref AWS::AccountId
Ec2Index: !Ref Ec2Index
AuthLogin: !Ref AuthLogin
Ec2Patch: !Ref Ec2Patch
AutoScalingIndex: !Ref AutoScalingIndex
AutoScalingPatch: !Ref AutoScalingPatch
AutoScalingScale: !Ref AutoScalingScale
In my swagger file:
paths:
/auth/session:
post:
produces:
- application/json
x-amazon-apigateway-integration:
uri: arn:aws:apigateway:ap-southeast-1:lambda:path/2015-03-31/functions/arn:aws:lambda:ap-southeast-1:598545985414:function:${stageVariables.AuthLogin}/invocations
passthroughBehavior: when_no_match
httpMethod: POST
type: aws_proxy
responses:
200:
description: App token
401:
description: 401
403:
description: 403
AWS CloudFormation errors saying
Errors found during import: Unable to put integration on 'POST' for resource at path '/auth/session': Lambda function ARN must be in same account Unable to put integration on 'GET' for resource at path '/autoscaling': Lambda function ARN must be in same account Unable to put integration on 'PATCH' for resource at path '/autoscaling/{groupName}': Lambda function ARN must be in same account Unable to put integration on 'POST' for resource at path '/autoscaling/{groupName}/scale': Lambda function ARN must be in same account Unable to put integration on 'GET' for resource at path '/ec2': Lambda function ARN must be in same account Unable to put integration on 'PATCH' for resource at path '/ec2/{id}': Lambda function ARN must be in same account
Seems like my ARN is invalid. This is resolved once I remove the variables. Whats wrong here?

Answer 1

As of now swagger does not allow AccountId in stage variables. It's a limitation of the API Gateway.
You can get around this by just using a stage variable for the function name only and piece the rest together like this:
//does not get passed in. This is just a placeholder for the stage variable
Parameters:
ApiFunctionName:
Type: String
Description: Function name of the api lambda function
Default: ${stageVariables.yourFunctionNameVar}
//in your gateway path
x-amazon-apigateway-integration:
httpMethod: POST
type: aws_proxy
uri:
!Sub "arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:${ApiFunctionName}/invocations"

Answer 2

Passing variables to swagger is not possible to do at this moment from a SAM template, but you can copy entire swagger file in the template file as DefinitionBody and reference variables the same way provided swagger definition is not huge.
SAM template is currently limited to 51.2 KB