CDK split API Gateway stack into 2 small stacks

Question

I\'m trying to create a CDK stack in order to create API Gateway. Everything working as excepted if I create the stack in "small pieces" (comment part of the resources

Answer 1

I think you can achieve your goal by separating resources into smaller stacks. It doesn't seem like you need cross stack references or nested stacks.

Here is an example (in Python) with 295 resources split between two stacks.

#!/usr/bin/env python3

from aws_cdk import core

from lambda_api.lambda_api_stack import APIStack
from lambda_api.lambda_api_stack import LambdasStack


app = core.App()
lambdas_stack = LambdasStack(app, 'lambdasstack')
APIStack(app, 'apistack', lambdas=lambdas_stack.lambdas)


app.synth()

from aws_cdk import (
    aws_apigateway as apigateway,
    aws_lambda as _lambda,
    aws_s3 as s3,
    core
)


class LambdasStack(core.Stack):

    @property
    def lambdas(self):
        return self._lambdas

    def __init__(self, scope: core.Construct, id: str, **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        self._lambdas = list()
        for i in range(48):
            handler = _lambda.Function(
                self, f'Handler_{i}',
                function_name=f'Handler_{i}',
                runtime=_lambda.Runtime.PYTHON_3_8,
                code=_lambda.Code.from_asset('resources'),
                handler='handler.main'
            )
            self._lambdas.append(handler)


class APIStack(core.Stack):

    def __init__(self, scope: core.Construct, id: str, lambdas: list,
            **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        api = apigateway.RestApi(
            self, 'lambdas-api',
            rest_api_name='Lambdas Service',
            description='This service serves lambdas.'
        )

        for i in range(len(lambdas)):
            get_lambda_integration = apigateway.LambdaIntegration(
                lambdas[i],
                request_templates={
                    'application/json':
                    '{ "statusCode": "200" }'
                }
            )
            model = api.root.add_resource(f'Resource_{i}')
            model.add_method('GET', get_lambda_integration)

For this example, the API resource + Lambda integrations generate the most resources. Here is an outline of the resources created.

97 resources are created in lambdasstack.

• 1 AWS::CDK::Metadata
• 48 x 2 resources
  • 1 AWS::Lambda::Function
  • 1 AWS::IAM::Role

198 resources are created in apistack.

• 1 AWS::CDK::Metadata
• 1 AWS::ApiGateway::Account
• 1 AWS::IAM::Role
• 1 AWS::ApiGateway::RestApi
• 1 AWS::ApiGateway::Deployment
• 1 AWS::ApiGateway::Stage
• 48 x 4 resources
  • 1 AWS::ApiGateway::Resource
  • 1 AWS::ApiGateway::Method
  • 2 AWS::IAM::Role