如何在无服务器框架的“serverless.yml”文件中获取 URL 端点详细信息作为变量？

Question

Using Serverless Framework to deploy AWS Lambda functions, Serverless creates (or receives) the specific URL endpoint string. I want to use that string (as a variable) in another section of the serverless.yml specification file.

Is that URL endpoint available as a variable in serverless.yml ? The Serverless Framework documentation on AWS-related variables does not seem to answer that case.

---

Details: my serverless.yml contains a provider: specification similar to:

provider:
  name: aws
  runtime: python3.6
  memorySize: 512
  region: ${opt:region, 'eu-west-1'}
  profile: ${opt:profile, 'default'}
  stage: ${opt:stage, 'staging'}

and a functions: section starting with:

functions:
  round-control:
    name: ${self:provider.stage}-round-control
    runtime: nodejs8.10
    handler: round/control/app.lambdaHandler
    events:
      - http:
          path: round/control
          method: get

After a

serverless deploy --profile [my-aws-profile]

the Lambda function sample-experiments-staging-round-control is reported to be available at endpoint https://1a234bc5de.execute-api.eu-west-1.amazonaws.com/staging/round/control .

Question: is there a variable in Serverless available that contains that 1a234bc5de , or 1a234bc5de.execute-api or perhaps even 1a234bc5de.execute-api.eu-west-1.amazonaws.com ? (Obviously, I can also construct the last two if I know the first.)

With that variable, I can construct the full URL endpoint, which I need in another place in the serverless.yml file.

NB That 1a234bc5de isn't a dynamically generated random string - my current project is (per stage, per region) 'fixed' to the same string. Perhaps that string is generated at AWS Lambda or AWS API Gateway?

Answer 1

I was able to pass the URL and unique ID for the API Gateway endpoint to a Lambda function as environment variables as follows:

  mylambda:
    handler: mylambda.handler
    runtime: python3.7
    events:
    - http:
        path: id
        cors: true
    environment:
      APIG_UID: !Ref "ApiGatewayRestApi"
      APIG_URL:
        !Join
          - ''
          - - 'https://'
            - !Ref ApiGatewayRestApi
            - '.execute-api.'
            - ${opt:region, self:provider.region}
            - '.amazonaws.com/'
            - ${opt:stage, self:provider.stage}

Thanks to goingserverless .

Answer 2

Here is a simpler and more modern alternative:

provider:
  environment:
    API_URL: !Sub 'https://${ApiGatewayRestApi}.execute-api.${aws:region}.amazonaws.com/${sls:stage}'

Note: ask asked in the question, this applies for REST API , not HTTP API .