Discussion on: Configuring Serverless Framework for multiple stages

[Alaa-Mahmoud]

i have the same issue i want to deploy multi stages on the same api gateway like we can do from AWS dashboard without creating a new stack , have u found a solution for this ?

[Ken Choong]

If you want to deploy multiple stage with same API,

You can:

• Make multiple stage : dev and prod
• State stageVariable for both stage
• Create a new version for your Lambda, for example it is Version:1
• Create 2 alias of Lambda: dev and prod
• Then make dev alias point to $Latest version
• Make prod alias point to Version:1 (Created at step above)
• Then in your method -> Put/Get/Post-> Integration Request -> Lamba Function-> set the value to: your-lambda-arn:${stageVariables.lambdaAlias} (Note that lambaAlias is what you set at stageVariable above

Then you done. The idea here is,

• prod api stage with stage variable prod point to prod lambda alias which will point to version 1
• dev api stage with stage variable dev point to dev lambda alias which will always point to $Latest

So by this, prod api endpoint will always go to Version 1, which will never changed.
Then you continue the development that will always changing and test. By this, any changes only will happen in api dev stage and wont fucked up in production stage. Production will stay unchanged.

All the stuff will inside 1 stack

I done this all using CDK. You can try in console. Just my 2 cents. hope you find helpful

[kotireddy555]

Really useful, Trying to implement the same however I am struggling to pass the below configuration using serverless yaml.

Put/Get/Post-> Integration Request -> Lamba Function-> set the value to: your-lambda-arn:${stageVariables.lambdaAlias}

Can you please share your thoughts? any snippet?

[Ken Choong]

I using CDK. so I share some of the snippet, then you will get the idea, not sure about Serverless yaml, never used serverless framework.

First define a API uri like this in a CDK contrust

 `   
 class ApiIntegration(core.Construct):
   @property
   def integration(self):
       return self._integration

   def __init__(self, scope: core.Construct, id: str, function: _lambda,  ** kwargs):
      super().__init__(scope, id, **kwargs)

      api_uri = (  # this API uri
          f"arn:aws:apigateway:"
          f"{core.Aws.REGION}"
          f":lambda:path/2015-03-31/functions/"
          f"{function.function_arn}"
          f":"
          f"${{stageVariables.lambdaAlias}}"
          f"/invocations"
       )

      self._integration = apigateway.Integration(
          type=apigateway.IntegrationType.AWS_PROXY,
          integration_http_method="POST", ## here is always POST. 
          uri=api_uri
       )`

The api_uri will make a endpoint to your lambda. The idea is make a URL for your lambda, then APIgateway will call to this URL for integration.

For the URI I define above, you can look at this example (The URI part in Open 3.0) :
docs.aws.amazon.com/apigateway/lat...

And this one, read at the 6th item
docs.aws.amazon.com/apigateway/lat...

If you using CDK, then you integrate your Apigateway like this:

          api = apigateway.LambdaRestApi(
                      self, "YourApiName",
                       #.. all other stuff 
                  )

          # The contruct define above. 
          my_api_integration = ApiIntegration(self, "MyApiIntegration", function="MyFunctionLambda") 

          # pass the constuct to the method 
         my_api_method = api.add_method(
           "POST", integration=my_api_integration.integration)

So I think in your serverless.yaml, you need to define the API uri like I done above. So the process look like this

User make request -> hit your apigateway endpoint -> apigateway hit your lambda using the "API uri"

Why api_uri?

This is the only way you can pass the {stageVariable.lambdaAlias} value to the lambda. When you get this value inside the lambda, then you can do other crazy shit depends to this lambdaAlias value.

So you get the idea. And remember, grant the apigateway endpoint permission to invoke your lambda.

[Ken Choong]

Recently I answer a question about this topic in SO. If interested you can look it here. Cheers

[Ken Choong]

I have create a whole tutorial series in here using CDK about this topic as well, feel free to take a look