HttpAPI properties are ignored when CorsConfiguration is not specified

[kwojcik-blockether]

Description:

Let's take as an example the following template.yml:

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Parameters:
  Timeout:
    Type: Number
    Default: 40
  MemorySize:
    Type: Number
    Default: 2048
  Environment:
    Type: String
    Default: staging

Globals:
  Function:
    Timeout: !Ref Timeout
    MemorySize: !Ref MemorySize

Resources:
  ExampleOfHttpApi:
    Type: AWS::Serverless::HttpApi
    Properties:
      StageName: prod
      Description: "Some description"
      DisableExecuteApiEndpoint: True

  LambdaFunctionExample:
    Type: AWS::Serverless::Function
    Properties:
      Policies:
        - Version: "2012-10-17"
          Statement:
          - Effect: "Allow"
            Action:
              - "ec2:CreateNetworkInterface"
              - "ec2:DeleteNetworkInterface"
              - "ec2:DescribeNetworkInterfaces"
              - "ec2:DetachNetworkInterface"
            Resource: "*"
      VpcConfig:
        SecurityGroupIds:
          - "sg-0022f72578ac5b373"
        SubnetIds:
          - "subnet-09e403ca9d13578df"
          - "subnet-00eb630443da8fc42"
          - "subnet-0833fa017fa879075"
      FunctionName: !Sub "LambdaFunctionExample-${Environment}"
      PackageType: Image
      Events:
        HttpProxyEvent:
          Type: HttpApi
          Properties:
            ApiId: !Ref ExampleOfHttpApi
            Path: /{proxy+}
            Method: ANY
    Metadata:
      DockerTag: v1
      DockerContext: .
      Dockerfile: Dockerfile

This is perfectly valid template. What I found surprising is that the following properties are ignored:

• HttpApi::Description
• HttpApi::StageName
• HttpApi::DisableExecuteApiEndpoint

Hovewer after adding CorsConfiguration the above specified properties works.

Steps to reproduce:

1. Modify the template

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Parameters:
  Timeout:
    Type: Number
    Default: 40
  MemorySize:
    Type: Number
    Default: 2048
  Environment:
    Type: String
    Default: staging

Globals:
  Function:
    Timeout: !Ref Timeout
    MemorySize: !Ref MemorySize

Resources:
  ExampleOfHttpApi:
    Type: AWS::Serverless::HttpApi
    Properties:
      StageName: prod
      Description: "Some description"
      DisableExecuteApiEndpoint: True

  LambdaFunctionExample:
    Type: AWS::Serverless::Function
    Properties:
      Policies:
        - Version: "2012-10-17"
          Statement:
          - Effect: "Allow"
            Action:
              - "ec2:CreateNetworkInterface"
              - "ec2:DeleteNetworkInterface"
              - "ec2:DescribeNetworkInterfaces"
              - "ec2:DetachNetworkInterface"
            Resource: "*"
      VpcConfig:
        SecurityGroupIds:
          - "sg-0022f72578ac5b373"
        SubnetIds:
          - "subnet-09e403ca9d13578df"
          - "subnet-00eb630443da8fc42"
          - "subnet-0833fa017fa879075"
      FunctionName: !Sub "LambdaFunctionExample-${Environment}"
      PackageType: Image
      Events:
        HttpProxyEvent:
          Type: HttpApi
          Properties:
            ApiId: !Ref ExampleOfHttpApi
            Path: /{proxy+}
            Method: ANY
    Metadata:
      DockerTag: v1
      DockerContext: .
      Dockerfile: Dockerfile

2. Run sam build
3. Run sam deploy --guided

Expected result:

I would expect that CorsConfiguration would not be required as it's specified in the documentation.
https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-httpapi.html#sam-httpapi-corsconfiguration

Additional environment details (Ex: Windows, Mac, Amazon Linux etc)

1. OS: Linux
2. sam --version: 1.31.0
3. AWS region: eu-central-1

[hoffa]

I've been unable to reproduce (i.e. the expected API configuration is deployed) so far with the following template:

AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31

Parameters:
  Timeout:
    Type: Number
    Default: 40
  MemorySize:
    Type: Number
    Default: 2048
  Environment:
    Type: String
    Default: staging

Globals:
  Function:
    Timeout: !Ref Timeout
    MemorySize: !Ref MemorySize

Resources:
  ExampleOfHttpApi:
    Type: AWS::Serverless::HttpApi
    Properties:
      StageName: prod
      Description: "Some description"
      DisableExecuteApiEndpoint: True

  LambdaFunctionExample:
    Type: AWS::Serverless::Function
    Properties:
      Runtime: python3.9
      Handler: index.handler
      InlineCode: |
        def handler(event, context):
            return {'foo': 'bar'}
      Policies:
        - Version: "2012-10-17"
          Statement:
            - Effect: "Allow"
              Action:
                - "ec2:CreateNetworkInterface"
                - "ec2:DeleteNetworkInterface"
                - "ec2:DescribeNetworkInterfaces"
                - "ec2:DetachNetworkInterface"
              Resource: "*"
      FunctionName: !Sub "LambdaFunctionExample-${Environment}"
      Events:
        HttpProxyEvent:
          Type: HttpApi
          Properties:
            ApiId: !Ref ExampleOfHttpApi
            Path: /{proxy+}
            Method: ANY

[hoffa]

Can't reproduce with PackageType: Image either:

sam init --name sam-app --package-type Image --base-image amazon/nodejs14.x-base
cd sam-app

With following template:

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Parameters:
  Timeout:
    Type: Number
    Default: 40
  MemorySize:
    Type: Number
    Default: 2048
  Environment:
    Type: String
    Default: staging

Globals:
  Function:
    Timeout: !Ref Timeout
    MemorySize: !Ref MemorySize

Resources:
  ExampleOfHttpApi:
    Type: AWS::Serverless::HttpApi
    Properties:
      StageName: prod
      Description: "Some description"
      DisableExecuteApiEndpoint: True

  LambdaFunctionExample:
    Type: AWS::Serverless::Function
    Properties:
      Policies:
        - Version: "2012-10-17"
          Statement:
          - Effect: "Allow"
            Action:
              - "ec2:CreateNetworkInterface"
              - "ec2:DeleteNetworkInterface"
              - "ec2:DescribeNetworkInterfaces"
              - "ec2:DetachNetworkInterface"
            Resource: "*"
      FunctionName: !Sub "LambdaFunctionExample-${Environment}"
      PackageType: Image
      Events:
        HttpProxyEvent:
          Type: HttpApi
          Properties:
            ApiId: !Ref ExampleOfHttpApi
            Path: /{proxy+}
            Method: ANY
    Metadata:
      DockerTag: v1
      DockerContext: ./hello-world
      Dockerfile: Dockerfile

Only differences with your template is the lack of VpcConfig, and using ./hello-world for DockerContext.

Just to clarify, by

the following properties are ignored

do you mean that the default values are used?

[kwojcik-blockether]

@hoffa My bad. Please try this:

sam init --name sam-app --package-type Image --base-image amazon/nodejs14.x-base
cd sam-app

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  sam-app

  Sample SAM Template for sam-app
  
Parameters:
  Timeout:
    Type: Number
    Default: 40
  MemorySize:
    Type: Number
    Default: 2048
  Environment:
    Type: String
    Default: staging

Globals:
  Function:
    Timeout: !Ref Timeout
    MemorySize: !Ref MemorySize

Resources:
  ServerlessHttpApi:
    Type: AWS::Serverless::HttpApi
    Properties:
      StageName: prod
      Description: "Some description"
      DisableExecuteApiEndpoint: True

  LambdaFunctionExample:
    Type: AWS::Serverless::Function
    Properties:
      Policies:
        - Version: "2012-10-17"
          Statement:
          - Effect: "Allow"
            Action:
              - "ec2:CreateNetworkInterface"
              - "ec2:DeleteNetworkInterface"
              - "ec2:DescribeNetworkInterfaces"
              - "ec2:DetachNetworkInterface"
            Resource: "*"
      FunctionName: !Sub "LambdaFunctionExample-${Environment}"
      PackageType: Image
      Events:
        HttpProxyEvent:
          Type: HttpApi
          Properties:
            ApiId: !Ref ServerlessHttpApi
            Path: /{proxy+}
            Method: ANY
    Metadata:
      DockerTag: v1
      DockerContext: ./hello-world
      Dockerfile: Dockerfile

Edit: it seems that it's not about CorsConfiguration but the ServerlessHttpApi resource.

[hoffa]

Thanks! Starting from what you gave, I was able to reproduce with a minimal example:

sam init --name sam-app --runtime python3.8 --dependency-manager pip --app-template hello-world
cd sam-app

Replace template.yaml:

Transform: AWS::Serverless-2016-10-31
Resources:
  ServerlessHttpApi:
    Type: AWS::Serverless::HttpApi
    Properties:
      StageName: prod
      Description: "Some description"
      DisableExecuteApiEndpoint: True

  LambdaFunctionExample:
    Type: AWS::Serverless::Function
    Properties:
      Runtime: python3.8
      Handler: index.handler
      InlineCode: |
        def handler(event, context):
            return {'foo': 'bar'}
      Events:
        HttpProxyEvent:
          Type: HttpApi
          Properties:
            ApiId: !Ref ServerlessHttpApi
            Path: /{proxy+}
            Method: ANY

Which deploys an API with default stage name, no description and execute API enabled.

Furthermore, removing Events altogether generates the expected CloudFormation (observed by running sam validate --debug, which outputs a translated template).

[CoshUS]

This is caused by overriding the generated implicit ServerlessHttpApi resource. If you change the logical ID to something else, description will be added to the body.

"ServerlessHttpApi2": {
      "Type": "AWS::ApiGatewayV2::Api", 
      "Properties": {
        "Body": {
          "info": {
            "version": "1.0", 
            "description": "Some description", 
            "title": {
              "Ref": "AWS::StackName"
            }
          }, 

[CoshUS]

FYI: Overriding ServerlessHttpApi is not recommended. We will be adding a warning on this use case: aws/aws-sam-cli#2907

[kwojcik-blockether]

Please make it an error. This mistake cost me few hours of dev.

[CoshUS]

Please make it an error. This mistake cost me few hours of dev.

We can't make this an error as it will create regressions on existing use cases. However, once we have the warnings added, it should be a lot easier to find where the root cause is.