How can I use api gateway stages via cloudformation or sam?

Question

I am using AWS SAM to deploy my lambda and api gateway. Below is my template yaml file:

AWSTemplateFormatVersion: \'2010-09-09\'
Transform: AWS:         


        

Answer 1

Typically what you would do is set the stage variable for the API in the template (maybe getting it through SSM parameter store, or just passing it through manually). Then, you would deploy the template as stage = "dev", and stage = "prod", as two separate deployments.

Here is an example (notice the "Stage" parameter, and then the !Sub ${Stage} in the API path):

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  sam-app

  Sample SAM Template for sam-app

Parameters:
  Stage:
    Type: String
    Default: Dev  #you would change this for dev/prod

# More info about Globals: https://github.com/awslabs/serverless-application-model/blob/master/docs/globals.rst
Globals:
  Function:
    Timeout: 3

Resources:
  HelloWorldFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: hello-world/
      Handler: app.lambdaHandler
      Runtime: nodejs8.10
      Events:
        HelloWorld:
          Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
          Properties:
            Path: /hello
            Method: post

Outputs:
  # ServerlessRestApi is an implicit API created out of Events key under Serverless::Function
  # Find out more about other implicit resources you can reference within SAM
  # https://github.com/awslabs/serverless-application-model/blob/master/docs/internals/generated_resources.rst#api
  HelloWorldApi:
    Description: "API Gateway endpoint URL for Prod stage for Hello World function"
    Value: !Sub "https://${ServerlessRestApi}.execute-api.${AWS::Region}.amazonaws.com/${Stage}/hello/"
  HelloWorldFunction:
    Description: "Hello World Lambda Function ARN"
    Value: !GetAtt HelloWorldFunction.Arn
  HelloWorldFunctionIamRole:
    Description: "Implicit IAM Role created for Hello World function"
    Value: !GetAtt HelloWorldFunctionRole.Arn

You can then use UsagePlans per stage, or different API keys per stage to better manage your API