title: AWS SAM template with API gateway only?
body: <p>We're planning to use API Gateway as REST API HTTP proxy only initially - as we have existing REST service and we wish to split it into smaller parts under covers without changing client interface (possibly later replacing some of those parts with lambda functions).</p>
  <p>Before we do that, I wish to see if we will have any support running such scenario locally, hence I've configured API gateway in AWS management console and exported OpenAPI definition.</p>
  <p>So my template.yaml looks like</p>
  <pre><code>AWSTemplateFormatVersion: '2010-09-09'
  Transform: 'AWS::Serverless-2016-10-31'
  Description: Demo SAM API
  Resources:
    MyApi:
      Type: AWS::Serverless::Api
      Properties:
        StageName: test
        DefinitionBody:
          'Fn::Transform':
            Name: AWS::Include
            Parameters:
              Location: swagger.yaml
  </code></pre>
  <p>and swagger.yaml looks following:</p>
  <pre><code>openapi: &quot;3.0.1&quot;
  info:
    title: &quot;Test.API&quot;
    description: &quot;Test.API&quot;
    version: &quot;2020-09-14T07:49:45Z&quot;
  servers:
  - url: &quot;https://dummydomain.com&quot;
  paths:
    /api/v3/Client:
      get:
        x-amazon-apigateway-integration:
          type: &quot;http_proxy&quot;
          uri: &quot;https://dummydommain.com/api/v3/client&quot;
          passthroughBehavior: &quot;when_no_match&quot;
          httpMethod: &quot;GET&quot;
          timeoutInMillis: 29000
  components: {}
  </code></pre>
  <p>And running <code>sam local start-api --debug</code> this gives error:</p>
  <pre><code>Error: Template does not have any APIs connected to Lambda functions
  </code></pre>
  <p>I've added dummy lambda function just to pass through the error, but still no luck - it had message in debug output:</p>
  <pre><code>Lambda function integration not found in Swagger document at path='/api/v3/client' method='get'
  </code></pre>
  <p>and responded to `http://localhost:3000/api/v3/client' with:</p>
  <pre><code>{&quot;message&quot;:&quot;Missing Authentication Token&quot;}
  </code></pre>
  <p>Does this mean, that SAM is very very coupled to lambda's and it won't run API gateway as proxy locally or I'm doing something stupid?</p>