Cannot access ApiGatewayRestApi in resources

Serverless Framework
1

I’m trying to deploy CloudFront together with my function to have the CDN capabilities in front of my API. I do this by adding Cloudfront as a resource to my serverless.yml, and referencing the Origin via the API Gateway Domain:

frameworkVersion: '3'

provider:
  name: aws

resources:
  Resources:
    CloudFrontDistribution:
      Type: AWS::CloudFront::Distribution
      Properties:
        DistributionConfig:
          Origins:
            - Id: ApiGateway
              DomainName:
                Fn::Join:
                  - "."
                  - - Ref: ApiGatewayRestApi
                    - execute-api
                    - Ref: AWS::Region
                    - amazonaws.com
     ...

functions:
  hello:
    handler: handler.hello
    events:
      - httpApi:
          path: /
          method: get

The problem is that Ref: ApiGatewayRestApi doesn’t work. All I get is an error:

The CloudFormation template is invalid: Template format error: Unresolved resource dependencies [ApiGatewayRestApi] in the Resources block of the template

If I hardcode the ID, the deployment works. How can I access the API Gateway ID within the resources? AFAIK the variable is defined here Serverless Framework - AWS Lambda Guide - AWS Infrastructure Resources and should be available, right?

2

Hey there. This page in the docs does not directly answer your question but may be what you need to get you in the right direction: Serverless Framework - AWS Lambda Events - API Gateway

3

Thanks for the hint!

I tried to define the API Gateway as a resource and link it to the provider.apiGateway, but the result is that CloudFront links to the API Gatway I defined in resources and the serverless function still has it’s own API Gateway. How can I make serverless uses also the API Gateway that I defined in resoucers?

service: learning-caching-headers
frameworkVersion: '3'

provider:
  name: aws
  runtime: nodejs12.x
  apiGateway:
    restApiId:
      'Fn::ImportValue': MyApiGateway-restApiId
    restApiRootResourceId:
      'Fn::ImportValue': MyApiGateway-rootResourceId

resources:
  Resources:
    MyApiGatewayRestApi:
      Type: AWS::ApiGateway::RestApi
      Properties:
        Name: ApiGatewayRestApiName
    CloudFrontDistribution:
      Type: AWS::CloudFront::Distribution
      Properties:
        DistributionConfig:
          Origins:
            - Id: ApiGateway
              DomainName:
                Fn::Join:
                  - "."
                  - - Ref: MyApiGatewayRestApi
                    - execute-api
                    - Ref: AWS::Region
                    - amazonaws.com
         ...
  Outputs:
    apiGatewayRestApiId:
      Value:
        Ref: MyApiGatewayRestApi
      Export:
        Name: MyApiGateway-restApiId
    apiGatewayRestApiRootResourceId:
      Value:
        Fn::GetAtt:
          - MyApiGatewayRestApi
          - RootResourceId
      Export:
        Name: MyApiGateway-rootResourceId

functions:
  hello:
    handler: handler.hello
    memorySize: 128
    events:
      - httpApi:
          path: /
          method: get

Also, why can’t I just reference to the API ID that is generated by serverless? My serverless.yml feels quite complicated.

4

I got the error! I was using the new HTTP API instead of the REST API. Changing httpApi to http in my function declaration made it work.

service: learning-caching-headers
frameworkVersion: '3'

provider:
  name: aws
  runtime: nodejs12.x

resources:
  Description: "CloudFormation template for ${self:service}"
  Resources:
    CloudFrontDistribution:
      Type: AWS::CloudFront::Distribution
      Properties:
        DistributionConfig:
          Origins:
            - Id: ApiGateway
              DomainName:
                Fn::Join:
                  - "."
                  - - Ref: ApiGatewayRestApi
                    - execute-api
                    - Ref: AWS::Region
                    - amazonaws.com
    ...

functions:
  hello:
    handler: handler.hello
    memorySize: 128
    events:
      - http:
          path: /
          method: GET

One last question: Is it possible to also reference the httpApi ID in the Cloudformation resource? I tried Ref: AWS::ApiGatewayV2::Api but it didn’t work. I also couldn’t find any reference here Serverless Framework - AWS Lambda Guide - AWS Infrastructure Resources

5

Also got the HTTP API reference resolved.

resources:
  Resources:
    CloudFrontDistribution:
      Type: AWS::CloudFront::Distribution
      Properties:
        DistributionConfig:
          Origins:
            - Id: ApiGateway
              DomainName:
                Fn::Join:
                  - "."
                  - - Ref: HttpApi
                    - execute-api
                    - Ref: AWS::Region
                    - Ref: AWS::URLSuffix

functions:
  hello:
    handler: handler.hello
    memorySize: 128
    events:
      - httpApi:
          path: /
          method: GET