sample-serverless.yml

service: my-api-gateway

provider:
  name: aws
  runtime: nodejs6.10
  region: sa-east-1
  stage: v1
  deploymentBucket: ${env:DEPLOYMENT_BUCKET}
  iamRoleStatements:
    - Effect: Allow
      Action: 
        - cloudwatch:*
        - logs:*
        - xray:*
        - dynamodb:*
      Resource: "*"

functions:
  get:
    name: my-api-gateway-get-${self:provider.stage}
    handler: handler.get
    description: Function to get
    memorySize: 512
    timeout: 30
    events:
      - http:
          method: GET
          path: service
          cors: true
  post:
    name: my-api-gateway-post-${self:provider.stage}
    handler: handler.get
    description: Function to post
    memorySize: 512
    timeout: 30
    events:
      - http:
          method: POST
          path: service
          cors: true
    environment:
      MY_ENV: ${env:MY_ENV}

custom:
  stage: "${opt:stage, self:provider.stage}"

resources:
  Resources:
    ApiGatewayRestApi:
      Type: AWS::ApiGateway::RestApi
      Properties:
        Name: ${self:service}-${self:custom.stage}
    #### Gateway Response INIT
    GatewayResponseDefault400:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: DEFAULT_4XX
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-4XX-generic\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseDefault500:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: DEFAULT_5XX
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-5XX-generic\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseAccessDeied:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: ACCESS_DENIED
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-403-access-denied\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseApiConfigurationError:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: API_CONFIGURATION_ERROR
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-500-api-configuration-error\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseAuthorizerConfigurationError:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: AUTHORIZER_CONFIGURATION_ERROR
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-500-authorizer-configuration-error\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseAuthorizerFailure:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: AUTHORIZER_FAILURE
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-500-authorizer-failure\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseBadRequestBody:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: BAD_REQUEST_BODY
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-400-bad-request-body\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseBadRequestParameters:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: BAD_REQUEST_PARAMETERS
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-400-bad-request-parameters\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseExpiredToken:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: EXPIRED_TOKEN
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-403-expired-token\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseIntegrationFailure:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: INTEGRATION_FAILURE
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-504-integration-failure\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseIntegrationTimeout:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: INTEGRATION_TIMEOUT
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-504-integration-timeout\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseInvalidApiKey:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: INVALID_API_KEY
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-403-invalid-api-key\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseInvalidSignature:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: INVALID_SIGNATURE
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-403-invalid-signature\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseMissingAuthenticationToken:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: MISSING_AUTHENTICATION_TOKEN
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-403-missing-authentication-token\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseQuotaExceeded:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: QUOTA_EXCEEDED
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-429-quota-exceeded\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseRequestTooLarge:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: REQUEST_TOO_LARGE
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-413-request-too-large\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseResourceNotFound:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: RESOURCE_NOT_FOUND
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-404-resource-not-found\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseThrottled:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: THROTTLED
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-429-throttled\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseUnauthorized:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: UNAUTHORIZED
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-401-unauthorized\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    GatewayResponseUnauthorizedMediType:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
        ResponseType: UNSUPPORTED_MEDIA_TYPE
        ResponseTemplates:
          application/json: "{\"error\":{\"code\":\"custom-415-unsupported-media-type\",\"message\":$context.error.messageString},\"requestId\":\"$context.requestId\"}"
    #### Gateway Response END
    DynamoDbTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: service-db
        AttributeDefinitions:
          - AttributeName: accessToken
            AttributeType: S
        KeySchema:
          - AttributeName: accessToken
            KeyType: HASH
        TimeToLiveSpecification:
          AttributeName: expires
          Enabled: true
        ProvisionedThroughput:
          ReadCapacityUnits: 5
          WriteCapacityUnits: 5

Hi @xflahertyx, did you find an answer to that? I'm struggling with the same problem

No. We only needed the custom authorizer because API Gateway uses the Content-MD5 header for it's own purposes and we needed to pass that header forward as context. Letting that lambda return the http response was simpler than trying to manage it with the authorizer configuration.