Now, let's create the API by using the CloudFormation template. We will not discuss the components that were already discussed in previous recipes, nor will we discuss the theory for commands that were already discussed within the CLI commands section. The complete code is available in the code files:

1. Start by defining the template version, Description, RestApi, and a path-part lambdagreeting.
2. Create a model for request validation, as follows:

MyRequestValidationModel:
  Type: AWS::ApiGateway::Model
  Properties:
    ContentType: application/json
    Description: Greeting Request Model
    Name: GreetingRequestModel
    RestApiId: !Ref MyRestAPI
    Schema: '{"$schema": "http://json-schema.org/draft-04/schema#",
              "title": "greetingModel",
              "type": "object",
              "properties": {
                "user" : {"type": "object",
                  "properties": {
                    "name" : {"type" : "string"}
                  }
                },
                "greeting" : {"type": "object",
                  "properties" : {
                    "time" : {"type" : "string"}
                  }
                }
              },
              "required" : ["user", "greeting"]
            }'

3. Create a request validator, as follows:

MyRequestValidator:
  Type: AWS::ApiGateway::RequestValidator
  Properties:
    Name: GreetingRequestValidator
    RestApiId: !Ref MyRestAPI
    ValidateRequestBody: true
    ValidateRequestParameters: false

4. Use the model and validator within the AWS::ApiGateway::Method resource, as follows:

MyMethod:
  Type: AWS::ApiGateway::Method
  Properties:
    AuthorizationType: NONE
    HttpMethod: POST
    Integration:
      Type: AWS
      IntegrationHttpMethod: POST
      PassthroughBehavior: WHEN_NO_TEMPLATES
      RequestTemplates:
        application/json: "{ "name" : $input.json('$.user.name'), "time": $input.json('$.greeting.time') }"
      IntegrationResponses:
      - StatusCode: 200
        ResponseTemplates:
          application/json: "{ "greeting" : $input.json('$.message')}"
      Uri:
        !Sub
          - 'arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:${AWS::AccountId}:function:${LAMBDA_NAME}/invocations'
          - LAMBDA_NAME: !ImportValue LambdaForApiGateway
    RequestModels:
      application/json: !Ref MyRequestValidationModel
    RequestValidatorId: !Ref MyRequestValidator
    ResourceId: !Ref GreetingResource
    RestApiId: !Ref MyRestAPI
    MethodResponses:
    - StatusCode: 200

5. Add deployment, add Lambda permissions, and add an Outputs section, similar to the previous recipes.