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

1. Start to create the template by defining AWSTemplateFormatVersion and a suitable Description.
2. Create the REST API by using AWS::ApiGateway::RestApi.
3. Create the path-part, lambdagreeting, by using AWS::ApiGateway::Resource.
4. Define the method, with the http-method as POST, as follows:

MyMethod:
  Type: AWS::ApiGateway::Method
  Properties:
    AuthorizationType: NONE
    HttpMethod: POST
    Integration:
      Type: AWS
      IntegrationHttpMethod: POST
      IntegrationResponses:
      - StatusCode: 200
      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

    ResourceId: !Ref GreetingResource
    RestApiId: !Ref MyRestAPI
    MethodResponses:
    - StatusCode: 200

5. Deploy our API to a stage, dev, by using AWS::ApiGateway::Deployment.

6. Add permission for the API to invoke the Lambda, as follows:

LambdaInvokePermission:
  Type: AWS::Lambda::Permission
  Properties:
    FunctionName: !ImportValue LambdaForApiGateway
    Action: 'lambda:InvokeFunction'
    Principal: apigateway.amazonaws.com
    SourceArn: !Sub
       - arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${API_ID}/*/POST/lambdagreeting
       - API_ID: !Ref MyRestAPI

7. Add an Outputs section with the updated URI, as follows:

Outputs:
  SampleEndpoint:
    Description: 'POST Endpoint'
    Value: !Sub
        - https://${API_ID}.execute-api.${AWS::Region}.amazonaws.com/dev/lambdagreeting
        - API_ID: !Ref MyRestAPI