Getting started with Cloud Endpoints on the App Engine flexible environment (.NET) with ESP

This tutorial shows you how to configure and deploy a sample .NET core API and the Extensible Service Proxy (ESP) running on an instance in the App Engine flexible environment. The sample code's REST API is described using the OpenAPI specification. The tutorial also shows you how to create an API key and use it in requests to the API.

For an overview of Cloud Endpoints, see About Endpoints and Endpoints architecture.


Use the following high-level task list as you work through the tutorial. All tasks are required to successfully send requests to the API.

  1. Set up a Google Cloud project, install the required software, and create an App Engine application. See Before you begin.
  2. Download the sample code. See Getting the sample code.
  3. Configure the openapi-appengine.yaml file, which is used to configure Endpoints. See Configuring Endpoints.
  4. Deploy the Endpoints configuration to create an Endpoints service. See Deploying the Endpoints configuration.
  5. Deploy the sample API and ESP to App Engine. See Deploying the API backend.
  6. Send a request to the API. See Sending a request to the API.
  7. Track API activity. See Tracking API activity.
  8. Avoid incurring charges to your Google Cloud account. See Clean up.


This tutorial uses the following billable components of Google Cloud:

To generate a cost estimate based on your projected usage, use the pricing calculator. New Google Cloud users might be eligible for a free trial.

When you finish this tutorial, you can avoid continued billing by deleting the resources you created. For more information, see Cleaning up.

Before you begin

  1. Sign in to your Google Account.

    If you don't already have one, sign up for a new account.

  2. In the Google Cloud Console, on the project selector page, select or create a Google Cloud project.

    Go to the project selector page

  3. Make sure that billing is enabled for your Cloud project. Learn how to confirm that billing is enabled for your project.

  4. Make a note of the project ID because it's needed later.
  5. This tutorial requires the .NET Core 2.x SDK, which you can use with any text editor. Although an integrated development environment (IDE) isn't required, for convenience, we recommend that you use one of the following IDEs:
  6. You need an application to send requests to the sample API. This tutorial provides an example using Invoke-WebRequest, which is supported in PowerShell 3.0 and later.

  7. Download the Cloud SDK.
  8. Update the Cloud SDK and install the Endpoints components.
    gcloud components update
  9. Make sure that the Cloud SDK (gcloud) is authorized to access your data and services on Google Cloud:
    gcloud auth login
    In the new browser tab that opens, select an account.
  10. Set the default project to your project ID.
    gcloud config set project YOUR_PROJECT_ID

    Replace YOUR_PROJECT_ID with your Google Cloud project ID. If you have other Google Cloud projects, and you want to use gcloud to manage them, see Managing Cloud SDK configurations.

  11. Select the region where you want to create your App Engine application. Run the following command to get a list of regions:
    gcloud app regions list
  12. Create an App Engine application. Replace YOUR_PROJECT_ID with your Google Cloud project ID and YOUR_REGION with the region that you want the App Engine application created in.
      gcloud app create \
      --project=YOUR_PROJECT_ID \

Getting the sample code

To download the sample API:

  1. Download the sample code as a zip file.

  2. Extract the zip file and change to the dotnet-docs-samples-master\endpoints\getting-started directory.

  3. Open GettingStarted.sln with Visual Studio, or use your favorite editor to edit the files in the endpoints\getting-started\src\IO.Swagger directory.

Configuring Endpoints

The sample code includes the OpenAPI configuration file, openapi-appengine.yaml, which is based on OpenAPI Specification v2.0.

To configure Endpoints:
  1. In the sample code directory, open the openapi-appengine.yaml configuration file.
    swagger: "2.0"
      description: "A simple Google Cloud Endpoints API example."
      title: "Endpoints Example"
      version: "1.0.0"
    host: ""

    Note the following:

    • The configuration sample displays the lines near the host field, which you need to modify. To deploy openapi-appengine.yaml to Endpoints, the complete OpenAPI document is required.
    • The example openapi-appengine.yaml contains a section for configuring authentication that isn't needed for this tutorial. You don't need to configure the lines with YOUR-SERVICE-ACCOUNT-EMAIL and YOUR-CLIENT-ID.
    • OpenAPI is a language-agnostic specification. The same openapi-appengine.yaml file is in the getting-started sample in each language GitHub repository for convenience.
  2. On the line with the host field, replace YOUR-PROJECT-ID with your Google Cloud project ID. For example:
    host: ""

Endpoints uses the text configured in the host field as the service name. When you deploy the API to the App Engine backend, a DNS entry with a name in the format is created automatically.

For information about the fields in the OpenAPI document that Endpoints requires, see Configuring Endpoints.

Deploying the Endpoints configuration

To deploy the Endpoints configuration, you use the gcloud endpoints services deploy command. This command uses Service Management to create a managed service.

To deploy the Endpoints configuration:

  1. Make sure you are in the endpoints/getting-started directory.
  2. Upload the configuration and create a managed service:
    gcloud endpoints services deploy openapi-appengine.yaml

The gcloud command then calls the Service Management API to create a managed service with the name that you specified in the host field of the openapi-appengine.yaml file. Service Management configures the service according to the settings in the openapi-appengine.yaml file. When you make changes to openapi-appengine.yaml, you must redeploy the file to update the Endpoints service.

As it is creating and configuring the service, Service Management outputs information to the terminal. You can safely ignore the warnings about the paths in the openapi-appengine.yaml file not requiring an API key. When it finishes configuring the service, Service Management displays a message with the service configuration ID and the service name, similar to the following:

Service Configuration [2017-02-13r0] uploaded for service []

In the preceding example, 2017-02-13r0 is the service configuration ID, and is the Endpoints service. The service configuration ID consists of a date stamp followed by a revision number. If you deploy the openapi-appengine.yaml file again on the same day, the revision number is incremented in the service configuration ID. You can view the Endpoints service configuration on the Endpoints > Services page in the Cloud Console.

If you get an error message, see Troubleshooting Endpoints configuration deployment.

Checking required services

At a minimum, Endpoints and ESP require the following Google services to be enabled:
Name Title Service Management API Service Control API Google Cloud Endpoints

In most cases, the gcloud endpoints services deploy command enables these required services. However, the gcloud command completes successfully but doesn't enable the required services in the following circumstances:

  • If you used a third-party application such as Terraform, and you don't include these services.

  • You deployed the Endpoints configuration to an existing Google Cloud project in which these services were explicitly disabled.

Use the following command to confirm that the required services are enabled:

gcloud services list

If you do not see the required services listed, enable them:

gcloud services enable
gcloud services enable
gcloud services enable

Also enable your Endpoints service:

gcloud services enable ENDPOINTS_SERVICE_NAME

To determine the ENDPOINTS_SERVICE_NAME you can either:

  • After deploying the Endpoints configuration, go to the Endpoints page in the Cloud Console. The list of possible ENDPOINTS_SERVICE_NAME are shown under the Service name column.

  • For OpenAPI, the ENDPOINTS_SERVICE_NAME is what you specified in the host field of your OpenAPI spec. For gRPC, the ENDPOINTS_SERVICE_NAME is what you specified in the name field of your gRPC Endpoints configuration.

For more information about the gcloud commands, see gcloud services.

Deploying the API backend

So far you have deployed the OpenAPI document to Service Management, but you haven't yet deployed the code that serves the API backend. This section walks you through deploying the sample API and ESP to App Engine.

To deploy the API backend:

  1. Open the endpoints/getting-started/src/IO.Swagger/app.yaml file, and add your service name:
  2. endpoints_api_service:
      # The following values are to be replaced by information from the output of
      # 'gcloud endpoints services deploy openapi-appengine.yaml' command. If you have
      # previously run the deploy command, you can list your existing configuration
      # ids using the 'configs list' command as follows:
      # 'gcloud endpoints configs list --service=[PROJECT-ID]'
      # where [PROJECT-ID] is your Endpoints service name.
      rollout_strategy: managed

    Replace ENDPOINTS-SERVICE-NAME with the name of your Endpoints service. This is the same name that you configured in the host field of your OpenAPI document. For example:

      rollout_strategy: managed

    The rollout_strategy: managed option configures ESP to use the latest deployed service configuration. When you specify this option, up to 5 minutes after you deploy a new service configuration, ESP detects the change and automatically begins using it. We recommend that you specify this option instead of a specific configuration ID for ESP to use.

  3. Save the app.yaml file.
  4. Because the endpoints_api_service section is included in the app.yaml file, the gcloud app deploy command deploys and configures ESP in a separate container to your App Engine flexible environment. All request traffic is routed through ESP, and it proxies requests and responses to and from the container running your backend server code.

  5. Make sure you are in the endpoints/getting-starteddirectory, which is where your openapi-appengine.yaml configuration file is located.
  6. Deploy the sample API and ESP to App Engine:
  7.     dotnet restore
        dotnet publish
        gcloud app deploy src\IO.Swagger\bin\Debug\netcoreapp2.0\publish\app.yaml

    The gcloud app deploy command creates a DNS record in the format, which you use when you send requests to the API. We recommend that you wait a few minutes before sending requests to your API while App Engine completely initializes.

If you get an error message, see Troubleshooting App Engine flexible deployment.

For more information, see Deploying the API Backend.

Sending requests to the API

After deploying the sample API, you can send requests to it.

Create an API key and set an environment variable

The sample code requires an API key. To simplify the request, you set an environment variable for the API key.

  1. In the same Google Cloud project that you used for your API, create an API key on the API credentials page. If you want to create an API key in a different Google Cloud project, see Enabling an API in your Google Cloud project.

    Go to the Credentials page

  2. Click Create credentials, and then select API key.
  3. Copy the key to the clipboard.
  4. Click Close.
  5. On your local computer, paste the API key to assign it to an environment variable: $Env:ENDPOINTS_KEY="AIza..."

Send the request

  1. In PowerShell, set an environment variable for your App Engine project URL. Replace YOUR_PROJECT_ID with your Google Cloud project ID.


  2. Test an HTTP request using the ENDPOINTS_HOST and ENDPOINTS_KEY environment variables you set previously:

    Invoke-WebRequest "$ENDPOINTS_HOST/echo?key=$ENDPOINTS_KEY" `
      -Body '{"message": "hello world"}' -Method POST `
      -ContentType "application/json"

In the previous example, the first two lines end in a backtick. When you paste the example into PowerShell, make sure there isn't a space following the backticks. For information about the options used in the example request, see Invoke-WebRequest in the Microsoft documentation.

The API echoes back the message that you send it, and responds with the following:

  "message": "hello world"

If you didn't get a successful response, see Troubleshooting response errors.

You just deployed and tested an API in Endpoints!

Tracking API activity

  1. View the activity graphs for your API in the Endpoints page.

    Go to the Endpoints Services page

    It may take a few moments for the request to be reflected in the graphs.

  2. Look at the request logs for your API in the Logs Viewer page.

    Go to the Logs Viewer page

Creating a developer portal for the API

You can use Cloud Endpoints Portal to create a developer portal, a website that you can use to interact with the sample API. To learn more, see Cloud Endpoints Portal overview.

Cleaning up

To avoid incurring charges to your Google Cloud account for the resources used in this tutorial, either delete the project that contains the resources, or keep the project and delete the individual resources.

See Deleting an API and API instances for information on stopping the services used by this tutorial.

What's next