Amplify Cloudformation Example - AppSync HTTP Datasource

CustomResources.json

{
  ...
"Resources": {
		"EmptyResource": {
			"Type": "Custom::EmptyResource",
			"Condition": "AlwaysFalse"
		},
		"MyDataSource": {
			"Type": "AWS::AppSync::DataSource",
			"Properties": {
				"ApiId": {
					"Ref": "AppSyncApiId"
				},
				"Type": "HTTP",
				"Name": "MyDataSource",
				"HttpConfig": {
					"Endpoint": "https://myapi.domain.com"
				}
			}
		},
		"QueryMyDataSourceResolver": {
			"Type": "AWS::AppSync::Resolver",
			"Properties": {
			  "ApiId": {
				  "Ref": "AppSyncApiId"
			  },
			  "DataSourceName": {
				  "Fn::GetAtt": [
            "MyDataSource",
            "Name"
          ]
			  },
			  "TypeName": "Query",
			  "FieldName": "myFieldName",
			  "RequestMappingTemplateS3Location": {
          "Fn::Sub": [
            "s3://${S3DeploymentBucket}/${S3DeploymentRootKey}/resolvers/Query.myFieldName.req.vtl",
            {
              "S3DeploymentBucket": {
                "Ref": "S3DeploymentBucket"
              },
              "S3DeploymentRootKey": {
                "Ref": "S3DeploymentRootKey"
              }
            }
          ]
			  },
			  "ResponseMappingTemplateS3Location": {
          "Fn::Sub": [
            "s3://${S3DeploymentBucket}/${S3DeploymentRootKey}/resolvers/Query.myFieldName.res.vtl",
            {
              "S3DeploymentBucket": {
                "Ref": "S3DeploymentBucket"
              },
              "S3DeploymentRootKey": {
                "Ref": "S3DeploymentRootKey"
              }
            }
          ]
			  }
			}
    }
	}
  ...
}

Query.myFieldName.req.vtl

#**
Inside folder api/apiname/resolvers
Make an arbitrary HTTP call when this field is listed in a query selection set.
The "relativePath" is the resource path relative to the root URL provided when you
created the HTTP data source. Pass a "params" object to forward headers, body,
and query parameters to the HTTP endpoint.
*#
{
  "version": "2018-05-29",
  "method": "GET",
  ## E.G. if full path is https://api.xxxxxxxxx.com/posts then resourcePath would be /posts **
  "resourcePath": "/path",
  "params": {
    "query":$util.toJson($ctx.args),
    "headers": {
        "Authorization": "$ctx.request.headers.Authorization"
    }
  }
}

Query.myFieldName.res.vtl

## Inside folder api/apiname/resolvers
## Raise a GraphQL field error in case of a datasource invocation error
#if($ctx.error)
  $util.error($ctx.error.message, $ctx.error.type)
#end
## If the response is not 200 then return an error. Else return the body **
#if($ctx.result.statusCode == 200)
    $ctx.result
#else
    $utils.appendError($ctx.result, $ctx.result.statusCode)
#end

schema.graphql

type MyModel {
  statusCode: Int!
  body: String!
}

type Query {
  myFieldName: MyModel
}