AWS Api Gateway to SQS integration (request.body to SQS)

template.yaml

# POST endpoint /update with a JSON payload like {"products": ["123", "456"]}.
# Api Gateway will send this payload to an SQS Queue.

AWSTemplateFormatVersion: 2010-09-09
Description: >-
  Api Gateway as a proxy to SQS.

Transform:
- AWS::Serverless-2016-10-31

Resources:
  SimpleQueue:
    Type: AWS::SQS::Queue

  ApiRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - apigateway.amazonaws.com
            Action:
              - sts:AssumeRole
      Policies:
        - PolicyName: SendMessageToSQSPolicy
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              Effect: Allow
              Action: sqs:SendMessage
              Resource: !GetAtt SimpleQueue.Arn
  
  Api:
    Type: "AWS::Serverless::Api"
    DependsOn:
      - ApiRole
    Properties:
      StageName: Prod
      DefinitionBody:
        swagger: "2.0"
        info:
          title: My app
          description: My app again
          version: 1.0
        paths:
          "/update":
            post:
              consumes:
                - application/json
              produces:
                - application/json
              parameters:
                - in: body
                  required: true
                  name: payload
                  description: The list of product codes to trigger
                  schema:
                    type: object
                    properties:
                      products:
                        type: array
                        items:
                          type: string
                    required:
                      - "products"
                    additionalProperties: false
              x-amazon-apigateway-request-validator: "ValidateBody"
              responses:
                "202":
                  description: on success
                "400":
                  description: invalid request body
              x-amazon-apigateway-integration:
                type: AWS
                httpMethod: POST
                passthroughBehavior: NEVER
                requestParameters:
                  integration.request.header.Content-Type: "'application/x-www-form-urlencoded'"
                requestTemplates:
                  "application/json": "Action=SendMessage&MessageBody=$input.body"
                credentials: !GetAtt ApiRole.Arn
                uri:
                  !Sub "arn:aws:apigateway:${AWS::Region}:sqs:path/${AWS::AccountId}/${SimpleQueue.QueueName}"
                responses:
                  default:
                    statusCode: "202"
                    responseTemplates:
                      application/json: '{"message": "Products sent for processing"}'
        x-amazon-apigateway-request-validators:
          ValidateBody:
            validateRequestParameters: false
            validateRequestBody: true
        x-amazon-apigateway-gateway-responses:
          BAD_REQUEST_BODY:
            responseTemplates:
              application/json: '{"error":{"message":"$context.error.messageString","errors":"$context.error.validationErrorString"}}'