resolvers.yml

functions:
  - dataSource: none_datasource
    name: todo_one
    requestMappingTemplate: '
      #set( $event = {
        "id": "test",
        "name": "Some todo"
      } )

      {
          "version" : "2018-05-29",
          "payload": $util.toJson($event)
      }
    '
    responseMappingTemplate: $util.toJson($context.result)
  - dataSource: none_datasource
    name: todo_two
    requestMappingTemplate: '
      #set( $event = {
        "id": $context.prev.result.id,
        "name": $context.prev.result.name,
        "description": 42,
        "priority": 123
      } )

      {
          "version" : "2018-05-29",
          "payload": $util.toJson($event)
      }
    '
    responseMappingTemplate:  $util.toJson($context.result)
resolvers:    
  - dataSource: none_datasource
    typeName: Query
    fieldName: getTodos
    requestMappingTemplate: >
      \#set( $payload = {
        "bar" : $context.request.foo
      } )

      {
          "version" : "2017-02-28",
          "operation": "Invoke",
          "payload": $util.toJson($payload)
      }
    responseMappingTemplate: $util.toJson($context.result)
  - typeName: Query
    fieldName: todo
    functions:
      - todo_one
      - todo_two
    requestMappingTemplate: '{}'
    responseMappingTemplate: $util.toJson($context.result)