How do I cloudform an API gateway resource with a lambda proxy integration - aws-lambda

Question

I've been trying to work out how to express (in cloudformation) an API Gateway Resource that has a Lambda function integration type using the Lambda Proxy integration.
This is easy to do in the AWS console as there is a check box that you can select:
However there is no corresponding field in the AWS::ApiGateway::Method CloudFormation resource (it should be in the Integration property).
How can I configure this in cloudformation?

Answer 1

The Integration type should be set to AWS_PROXY. An example snippet of a method from a working YAML CloudFormation template is below.
ProxyResourceAny:
Type: AWS::ApiGateway::Method
Properties:
AuthorizationType: NONE
HttpMethod: ANY
ResourceId:
Ref: ProxyResource
RestApiId:
Ref: API
Integration:
Type: AWS_PROXY
IntegrationHttpMethod: POST
Uri: !Sub
- arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${Arn}/invocations
- Arn:
Fn::GetAtt:
- RestorerLambda
- Arn
It's worth saying how a I figured this out...
After scratching my head for a while I examined the output of the aws apigateway get-method CLI command for a method that was configured this way using the console. That gave me the following JSON and I realised that the checkbox might be encoded into the type. I tested my assumption and came up with the CloudFormation above.
{
"apiKeyRequired": false,
"httpMethod": "ANY",
"methodIntegration": {
"integrationResponses": {
"200": {
"responseTemplates": {
"application/json": null
},
"statusCode": "200"
}
},
"passthroughBehavior": "WHEN_NO_MATCH",
"cacheKeyParameters": [],
"uri": "arn:aws:apigateway:eu-west-1:lambda:path/2015-03-31/functions/arn:aws:lambda:eu-west-1:XXXXXXXXX:function:Shildrew-Restorer-Play-Lambda/invocations",
"httpMethod": "POST",
"cacheNamespace": "64bl3tgw4g",
"type": "AWS_PROXY"
},
"requestParameters": {},
"authorizationType": "NONE"
}

Answer 2

I have solved this same issue by simple changing the
Integration:
Type: AWS_PROXY
To
Integration:
Type: AWS
The cloud formation documentation currently is scarce and the API gateway cloudformation documentation doesn't match up to what can be seen on the console which hinders anyone who is trying to resolve an issue.
Hope this helps!

Answer 3

We faced this exact issue. We are using Ansible for our Infrastructure. Could apply to CLI or Cloudformation or even the SDK
The solution to our problem was to make sure that the Lambda policy was defined in a granular manner for the endpoint verbs in API Gateway for the lambda you are attempting to use.
For instance, We had multiple routes. Each route(or sets of routes) needs its own lambda policy defined that allows lambda:InvokeFunction. This is defined in the Lambda Policy module for Ansible. With this, the lambda trigger was enabled automatically.

Answer 4

There are two ways to achieve this:
Method 1: By defining the "Lambda", "API Gateway", "API Resource" and "API Methods". Linking the Lambda using the URI statement under "API Method".
MyLambdaFunction:
Type: "AWS::Lambda::Function"
Properties:
Description: "Node.js Express REST API"
FunctionName: "get_list_function" (The name in AWS console)
Handler: lambda.handler
Runtime: nodejs12
MemorySize: 128
Role: <ROLE ARN>
Timeout: 60
apiGateway:
Type: "AWS::ApiGateway::RestApi"
Properties:
Name: "example-api-gw"
Description: "Example API"
ProxyResource:
Type: "AWS::ApiGateway::Resource"
Properties:
ParentId: !GetAtt apiGateway.RootResourceId
RestApiId: !Ref apiGateway
PathPart: '{proxy+}' OR "a simple string like "PetStore"
apiGatewayRootMethod:
Type: "AWS::ApiGateway::Method"
Properties:
AuthorizationType: NONE
HttpMethod: ANY
Integration:
IntegrationHttpMethod: POST
Type: AWS_PROXY
IntegrationResponses:
- StatusCode: 200
Uri: !Sub >-
arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${MyLambdaFunction.Arn}/invocations
ResourceId: !Ref ProxyResource
RestApiId: !Ref "apiGateway"
METHOD 2: Define "API Gateway" and "Lambda". In Lambda definitions, call Events of type API.
CoreApi:
Type: 'AWS::Serverless::Api'
Properties:
StageName: dev
Name: SaaSAPI
EndpointConfiguration: Regional
Cors:
AllowMethods: '''POST, GET, OPTIONS, PATCH, DELETE, PUT'''
AllowHeaders: '''Content-Type, X-Amz-Date, Authorization, X-Api-Key, x-requested-with'''
AllowOrigin: '''*'''
MaxAge: '''600'''
MyLambdaFunction:
Type: "AWS::Lambda::Function"
Properties:
Description: "Node.js Express REST API"
FunctionName: "get_list_function"
Handler: lambda.handler
Runtime: nodejs12
MemorySize: 128
Role: <ROLE ARN>
Timeout: 60
Events:
ProxyResourceA:
Type: Api
Properties:
Path: /Departments
Method: GET
RestApiId: !Ref CoreApi
ProxyResourceB:
Type: Api
Properties:
Path: /Departments (This becomes the resource in API Gateway)
Method: POST
RestApiId: !Ref CoreApi
(You can link multiple methods with the same lambda, provide a unique name to each event, like ProxyResoruceA & ProxyResourceB)