AWS::Serverless::Api Models removing keys from schema

[ldhbsg]

Hi. I am having some issues with the models section when deploying my API. Everything is deploying, but there seems to be a check that removes certain keys in the schema. Main ones I am having issues with adding are minProperties and maxProperties. Everything deploys but that those key value pairs are missing.

I have tried the exact same schema with the AWS::ApiGateway::Model and it works fine. It seems to be an issue when the requested resources in the SAM template get converted to CloudFormation. Can someone please help? minLength and maxLength do work on strings also I tried.

Also if I am doing it in the wrong way in SAM please do let me know. Although I do not think that is the issue as min and max Length do work as they should on the api model.

This is an example of the schema tried in both AWS::Serverless::Api and AWS::ApiGateway::Model:

required:
  - property1
  - property2
  - property3
  - property4
type: object
minProperties: 4
maxProperties: 4
properties:
  property1:
      type: string
      enum:
        - option1
        - option2
        - option3
  property2:
      type: string
      enum:
        - a
        - b
  property3:
      type: string
      pattern: ^[a-zA-Z0-9]+$
  property4:
      required:
        - test
      type: object
      maxProperties: 1
      properties:
        test:
            type: string
            enum:
              - small
              - medium
              - large

I have also tried additionalProperties and that one is being removed too.

[hoffa]

No solutions yet, but might be tangentially related: #1559.

[hoffa]

Meanwhile, could you provide a reproducible template to speed up investigations?

[ldhbsg]

Hi @hoffa ,
Please find below an example of the deployment. With both SAM and CFN created models. The models if you can see are the same in the template but maxProperties, minProperties and additionalProperties keys are removed from the SAM created ones when you look in the API Gateway section on the AWS Console. In the outputs section you will find an example off a passable and a failable API call (for SAM methods it works though due to the models missing keys on creation). All you have to do is place the relevant resource at the end of the API call.

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Globals:
  Function:
    Timeout: 30
    MemorySize: 256
    Runtime: python3.9
Resources:
  APIGateway:
    Type: AWS::Serverless::Api
    Properties:
      EndpointConfiguration: 
        Type: REGIONAL
      Description: API Gateway to test models
      Name: test-api
      StageName: test-api
      Models:
        model1a:
          required:
            - property1
            - property2
            - property3
            - property4
          type: object
          minProperties: 4
          maxProperties: 4
          properties:
            property1:
              type: string
              enum:
                - option1
                - option2
                - option3
            property2:
              type: string
              enum:
                - a
                - b
            property3:
              type: string
              pattern: ^[a-zA-Z0-9]+$
            property4:
              required:
                - test
              type: object
              minProperties: 1
              maxProperties: 1
              properties:
                test:
                  type: string
                  enum:
                    - small
                    - medium
                    - large
        model2a:
          required:
            - property1
            - property2
            - property3
            - property4
          type: object
          additionalProperties: false
          properties:
            property1:
              type: string
              enum:
                - option1
                - option2
                - option3
            property2:
              type: string
              enum:
                - a
                - b
            property3:
              type: string
              pattern: ^[a-zA-Z0-9]+$
            property4:
              required:
                - test
              type: object
              additionalProperties: false
              properties:
                test:
                  type: string
                  enum:
                    - small
                    - medium
                    - large
  Model1b:
    Type: AWS::ApiGateway::Model
    Properties:
      RestApiId: !Ref APIGateway
      ContentType: application/json
      Description: model 1 not with SAM
      Name: model1b
      Schema:
        required:
          - property1
          - property2
          - property3
          - property4
        type: object
        minProperties: 4
        maxProperties: 4
        properties:
          property1:
            type: string
            enum:
              - option1
              - option2
              - option3
          property2:
            type: string
            enum:
              - a
              - b
          property3:
            type: string
            pattern: ^[a-zA-Z0-9]+$
          property4:
            required:
              - test
            type: object
            minProperties: 1
            maxProperties: 1
            properties:
              test:
                type: string
                enum:
                  - small
                  - medium
                  - large
  Model2b:
    Type: AWS::ApiGateway::Model
    Properties:
      RestApiId: !Ref APIGateway
      ContentType: application/json
      Description: model 2 not with SAM
      Name: model2b
      Schema:
        required:
          - property1
          - property2
          - property3
          - property4
        type: object
        additionalProperties: false
        properties:
          property1:
            type: string
            enum:
              - option1
              - option2
              - option3
          property2:
            type: string
            enum:
              - a
              - b
          property3:
            type: string
            pattern: ^[a-zA-Z0-9]+$
          property4:
            required:
              - test
            type: object
            additionalProperties: false
            properties:
              test:
                type: string
                enum:
                  - small
                  - medium
                  - large
  Function:
    Type: AWS::Serverless::Function
    Properties:
      InlineCode: |
        import json
        def lambda_handler(event, context):
          return {
            'statusCode': 200,
            'body': json.dumps({
                'result': 'successful', 
            }),
          }
      Events:
        Model1aEvent:
          Type: Api
          Properties:
            Path: /model1a
            Method: POST
            RestApiId: !Ref APIGateway
            RequestModel:
              Model: model1a
              Required: true
              ValidateBody: true
        Model2aEvent:
          Type: Api
          Properties:
            Path: /model2a
            Method: POST
            RestApiId: !Ref APIGateway
            RequestModel:
              Model: model2a
              Required: true
              ValidateBody: true
      FunctionName: test-api
      Handler: index.lambda_handler
  Model1bAPIResource:
    Type: AWS::ApiGateway::Resource
    Properties:
      ParentId: !GetAtt APIGateway.RootResourceId
      PathPart: model1b
      RestApiId: !Ref APIGateway
  Model1bValidator:
    Type: AWS::ApiGateway::RequestValidator
    Properties: 
      Name: Model1b
      RestApiId: !Ref APIGateway
      ValidateRequestBody: true
  Model1bAPIMethod:
    DependsOn: Model1b
    Type: AWS::ApiGateway::Method
    Properties:
      AuthorizationType: NONE
      HttpMethod: POST
      Integration:
        IntegrationHttpMethod: POST
        Type: AWS_PROXY
        Uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${Function.Arn}/invocations
      ResourceId: !Ref Model1bAPIResource
      RestApiId: !Ref APIGateway
      RequestValidatorId: !Ref Model1bValidator
      RequestModels:
        application/json: model1b
  Model1bAPIFunctionPermission:
    Type: AWS::Lambda::Permission
    Properties:
      Action: lambda:InvokeFunction
      FunctionName: !Ref Function
      Principal: apigateway.amazonaws.com
      SourceArn: !Sub arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${APIGateway}/*/*/model1b
  Model2bAPIResource:
    Type: AWS::ApiGateway::Resource
    Properties:
      ParentId: !GetAtt APIGateway.RootResourceId
      PathPart: model2b
      RestApiId: !Ref APIGateway
  Model2bValidator:
    Type: AWS::ApiGateway::RequestValidator
    Properties: 
      Name: Model2b
      RestApiId: !Ref APIGateway
      ValidateRequestBody: true
  Model2bAPIMethod:
    DependsOn: Model2b
    Type: AWS::ApiGateway::Method
    Properties:
      AuthorizationType: NONE
      HttpMethod: POST
      Integration:
        IntegrationHttpMethod: POST
        Type: AWS_PROXY
        Uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${Function.Arn}/invocations
      ResourceId: !Ref Model2bAPIResource
      RestApiId: !Ref APIGateway
      RequestValidatorId: !Ref Model2bValidator
      RequestModels:
        application/json: model2b
  Model2bAPIFunctionPermission:
    Type: AWS::Lambda::Permission
    Properties:
      Action: lambda:InvokeFunction
      FunctionName: !Ref Function
      Principal: apigateway.amazonaws.com
      SourceArn: !Sub arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${APIGateway}/*/*/model2b
  Deployment:
    DependsOn: 
      - Model1bAPIMethod
      - Model2bAPIMethod
    Type: AWS::ApiGateway::Deployment
    Properties:
      RestApiId: !Ref APIGateway
      Description: test api models
      StageName: test-api
Outputs:
  WorkingBody:
    Description: This body should pass validation
    Value: !Sub 'curl -X POST -H "Content-Type: application/json" -d "{\"property1\" : \"option1\", \"property2\" : \"b\", \"property3\" : \"test\", \"property4\" : {\"test\" : \"medium\"} }" https://${APIGateway}.execute-api.${AWS::Region}.amazonaws.com/test-api/'
  NonWorkingBody:
    Description: This body should fail validation
    Value: !Sub 'curl -X POST -H "Content-Type: application/json" -d "{\"property1\" : \"option1\", \"property2\" : \"b\", \"property3\" : \"test\", \"property4\" : {\"test\" : \"medium\"}, \"property5\" : \"deny\"}" https://${APIGateway}.execute-api.${AWS::Region}.amazonaws.com/test-api/'

[ldhbsg]

You should get an Invalid Request Body response on model1b and model2b when you use the 'NonWorkingBody' call in the Outputs as they are created using CFN. Although they should all return that response.

[hoffa]

Thanks a lot for the example.

First, I checked the transform output, and compared the one using AWS::ApiGateway::Model and the Models from AWS::Serverless::Api. I didn't find any difference, so SAM isn't removing the properties.

However, I tried with this minimal template using raw CloudFormation:

Resources:
  MyRestApi:
    Type: AWS::ApiGateway::RestApi
    Properties:
      Body:
        swagger: "2.0"
        definitions:
          MyModel:
            additionalProperties: false
            type: object
            properties:
              someProperty:
                type: string

And deployed with:

sam deploy --region us-west-2 --resolve-s3 --capabilities CAPABILITY_IAM --stack-name test-2708 --template template.yaml

If I then look at the model in API Gateway, I see this:

{
  "type" : "object",
  "properties" : {
    "someProperty" : {
      "type" : "string"
    }
  }
}

It's missing additionalProperties. So it looks like an issue with API Gateway. Doesn't affect AWS::ApiGateway::Model.

I'll check whether this is documented; if not, I'll route this issue internally. Thanks for reporting it!

[hoffa]

Behavior arising from API Gateway; see #2708 (reply in thread). I've routed this issue internally.