Getting Started with Endpoints on App Engine Flexible Environment (.NET)

This tutorial shows you how to configure, deploy, and send requests to a sample .NET core API 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 the request to the API.

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

Task List

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 Cloud Platform project, install required software, and create an App Engine app. 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 a Cloud Endpoints service. See Deploying the Endpoints configuration.
  5. Create a backend to serve the API and deploy the API. 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 Platform account. See Clean 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. Select or create a Cloud Platform project.

    Go to the Manage resources page

  3. Enable billing for your project.

    Enable billing

  4. Note the project ID, because you'll need it later.
  5. Install cURL for testing purposes. On Windows, this tutorial uses PowerShell's built in WebRequest support.
  6. Download the Google Cloud SDK.
  7. Update the Cloud SDK and install the Endpoints components.
    gcloud components update
  8. Make sure that Cloud SDK (gcloud) is authorized to access your data and services on Google Cloud Platform:
    gcloud auth login
    A new browser tab opens and you are prompted to choose an account.
  9. Set the default project to your project ID.
    gcloud config set project [YOUR_PROJECT_ID]

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

  10. Select the region where you want to create your App Engine app. See App Engine Locations for a list of regions.
  11. Create an App Engine app using the following command. Replace [YOUR_PROJECT_ID] with your Cloud project ID and [YOUR_REGION] with the region that you want the App Engine app created in.
      gcloud app create \
      --project=[YOUR_PROJECT_ID] \
  12. Install .NET Core SDK.

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: ""

  2. On the line with the host field, replace YOUR-PROJECT-ID with your Cloud project ID. For example:
    host: ""

Cloud 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.

Note: The configuration sample above displays lines near the host field, which you need to modify. To run Cloud Endpoints, the complete configuration file is required.

Deploying the Endpoints configuration

To deploy the Endpoints configuration, you use Google Service Management, an infrastructure service of Google Cloud Platform that manages other APIs and services, including services created using Cloud Endpoints.

To deploy the Endpoints configuration:
  1. Make sure you are in the endpoints/getting-started directory.
  2. Invoke the following command:
    gcloud endpoints services deploy openapi-appengine.yaml

    This creates a new Cloud Endpoints service with the name that you specified in the host field of the openapi-appengine.yaml file (if it does not already exist). The service is updated according to your OpenAPI configuration file. No matter what the Endpoints service name is, when you deploy the API on App Engine, a DNS record is created using the name format, which is the FQDN that you use when you send requests to the API.

    As it is creating and configuring the service, Service Management outputs a great deal of information to the terminal. You can safely ignore the warnings about the paths in openapi-appengine.yaml not requiring an API key. On successful completion, you will see a line like the following that displays the service configuration ID and the service name:

    Service Configuration [2017-02-13-r2] uploaded for service []

In the above example, 2017-02-13-r2 is the service configuration ID and is the service name. If you get an error message, see Troubleshooting configuration deployment errors.

See gcloud endpoints services deploy in the Cloud SDK Reference documentation for more information.

Deploying the API backend

So far you have deployed the OpenAPI configuration to Service Management, but you have not yet deployed the code that will serve the API backend. This section walks you through deploying the sample API to App Engine.

To deploy the API backend:

  1. Display the service configuration ID, by entering the following:
    gcloud endpoints configs list --service=[YOUR-PROJECT-ID]
    In the above command, replace [YOUR-PROJECT-ID] with your project ID. Do not include the square brackets. For example:
    gcloud endpoints configs list
  2. Open endpoints/getting-started/src/IO.Swagger/app.yaml, and add your service name and service configuration ID:
  3. 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.
      config_id: ENDPOINTS-CONFIG-ID

    • Replace ENDPOINTS-SERVICE-NAME with your Endpoints service name.
    • Replace ENDPOINTS-CONFIG-ID with the service configuration ID displayed in the first step. For example:
      name: ""
      config_id: "2017-02-13-r2"
  4. Save the app.yaml file.
  5. Make sure you are in the endpoints/getting-starteddirectory, which is where your openapi-appengine.yaml configuration file is located.
  6. Run the following commands to deploy the sample API to App Engine:
  7.     dotnet restore
        dotnet publish
        gcloud app deploy src\IO.Swagger\bin\Debug\netcoreapp2.0\publish\app.yaml

    We recommend that you wait a few minutes before sending requests to your API while App Engine completely initializes.

Note: Anytime you make changes to your OpenAPI configuration file, you will need to update the service configuration ID in the app.yaml file and redploy it to App Engine.

Sending requests to the API

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

  1. In PowerShell, set a variable for your App Engine project URL:


    Replace [YOUR_PROJECT_ID] with your Cloud project ID.

  2. In the same GCP project that you used for your API, create an API key on the API credentials page. (See Enabling an API in Your Cloud Project if you want to create an API key in a different GCP project.)

    Create an API key

    1. Click Create credentials, then select API key.
    2. Copy the key to the clipboard.
    3. Click Close.
    4. On the Credentials page, click Save.
  3. Paste the key into the following PowerShell export statement:

  4. Test an HTTP request using the Invoke-WebRequest cmdlet and the ENDPOINTS_HOST and ENDPOINTS_KEY environment variables set previously:

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

Note: App Engine may take a few minutes to respond successfully to requests. If you send a request and get back an HTTP 502, 503, or some other server error, wait a minute and try the request again.

You just deployed and tested an API in Cloud Endpoints!

Tracking API activity

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

Clean up

To avoid incurring charges to your Google Cloud Platform account for the resources used in this quickstart:

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

What's next

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Cloud Endpoints with OpenAPI