[type-safe-api] Inject variables in Open API spec

[valebedu]

In a scenorio with AWS CloudFormation and inline REST API spec it is possible to do the following:

openapi: 3.0.3
info:
  version: 1.0.0
  title: My API
paths:
  /hello:
    get:
      operationId: sayHello
      parameters:
        - in: query
          name: name
          schema:
            type: string
          required: true
      responses:
        '200':
          description: Successful response
          content:
            'application/json':
              schema:
                $ref: '#/components/schemas/SayHelloResponseContent'
        '400':
          description: Error response
          content:
            'application/json':
              schema:
                $ref: '#/components/schemas/ApiErrorResponseContent'
      x-amazon-apigateway-integration:
        contentHandling: CONVERT_TO_TEXT
        credentials:
          Fn::Sub: ${CacheReadS3Role.Arn} # Variable
        httpMethod: GET
        passthroughBehavior: when_no_match
        responses:
          default:
            statusCode: 200
            responseParameters:
              method.response.header.Access-Control-Allow-Headers: "'Accept,Authorization,Content-Type,X-Amz-Date,X-Amz-Security-Token,X-Api-Key,X-Forwarded-For'"
              method.response.header.Access-Control-Allow-Methods: "'GET,OPTIONS'"
              method.response.header.Access-Control-Allow-Origin: "'*'"
              method.response.header.Access-Control-Max-Age: "'600'"
          4|5\d{2}:
            statusCode: 500
            responseParameters:
              method.response.header.Access-Control-Allow-Headers: "'Accept,Authorization,Content-Type,X-Amz-Date,X-Amz-Security-Token,X-Api-Key,X-Forwarded-For'"
              method.response.header.Access-Control-Allow-Methods: "'GET,OPTIONS'"
              method.response.header.Access-Control-Allow-Origin: "'*'"
              method.response.header.Access-Control-Max-Age: "'600'"
        timeoutInMillis: 19000
        type: aws
        uri:
          Fn::Sub: arn:${AWS::Partition}:apigateway:${AWS::Region}:s3:path/${CacheS3Bucket}/types/hello-types.json # Variable
components:
  schemas:
    ApiErrorResponseContent:
      type: object
      properties:
        errorMessage:
          type: string
      required:
        - errorMessage
    SayHelloResponseContent:
      type: object
      properties:
        message:
          type: string
      required:
        - message

As AWS integration is currently not supported the only way to achieve s3 integration is by writing the integration directly in the Open API spec file.

Is there a way to fill variables in the file ?

[cogwirrel]

Hey!

TypeSafeApi uses "Integrations" to construct the x-amazon-apigateway-integration part of the OpenAPI spec through CDK, rather than through variables in your template.

You can achieve the same as your above example by implementing a "custom integration" (see docs here).

Essentially, you can extend the Integration class and implement the render method to return the x-amazon-apigateway-integration part of the spec for your specific integration. See here for how Integrations.lambda is implemented for a simple example, or here for a more complex example for a Network Load Balancer.

Hope that helps!

Cheers,
Jack

[valebedu]

Thanks a lot @cogwirrel that helps a lot!