Enabling IAP for App Engine

This page explains how to secure an App Engine instance with Identity-Aware Proxy (IAP).

Before you begin

To enable IAP for App Engine, do the following:

1. Use a Google Cloud console project with billing enabled.

2. Make sure that the project belongs to a Google Cloud organization if you want to use the default Google-managed OAuth client. If you don't have an organization, you can create one. To learn about the benefits of using a custom OAuth client, see Configure custom OAuth clients for App Engine. The Google-managed OAuth client only allows access to internal users.

   Important: If your project doesn't belong to an organization or you want to allow access to users who are outside of your organization, you must use a custom OAuth configuration. Enabling IAP on a project without an organization or custom credentials causes requests to fail with an HTTP 502: Empty Google Account OAuth client ID(s)/secret(s) error.

3. Set up your App Engine instance, if you haven't already. For a complete walkthrough, see Deploying to App Engine.

Enable IAP

Console

If your project does not belong to an organization, you must use custom OAuth credentials.

If you haven't configured your project's OAuth consent screen, you'll be prompted to do so. To configure your OAuth consent screen, see Setting up your OAuth consent screen.

Setting up IAP access

1. Go to the Identity-Aware Proxy page.
   Go to the Identity-Aware Proxy page
2. Select the project you want to secure with IAP.
3. Select the checkbox next to the resource you want to grant access to.
4. On the right side panel, click Add principal.
5. In the Add principals dialog that appears, enter the email addresses of groups or individuals who should have the IAP-secured Web App User role for the project.

   The following kinds of principals can have this role:

   • Google Account: [e-mail]
   • Google Group: [e-mail]
   • Service account: server@example.
   • Google Workspace domain: example.com

   Make sure to add a Google Account that you have access to.

6. Select Cloud IAP > IAP-secured Web App User from the Roles drop-down list.
7. Click Save.

Turning on IAP

1. On the Identity-Aware Proxy page, under Applications, find the application you want to restrict access to. To turn on IAP for a resource, toggle the on/off switch in the IAP column.
   
2. In the Turn on IAP window that appears, click Turn On to confirm that you want IAP to secure your resource. After you turn on IAP, it requires login credentials for all connections to your load balancer. Only principals with the IAP-Secured Web App User (roles/iap.httpsResourceAccessor) role on the project will be given access.

gcloud

在设置项目和 IAP 之前，您需要最新版本的 gcloud CLI。如需了解如何安装 gcloud CLI，请参阅安装 gcloud CLI。

1. 如需进行身份验证，请使用 Google Cloud CLI 并运行以下命令。

   gcloud auth login

2. 点击显示的网址并登录。
3. 登录后，复制显示的验证码并将其粘贴到命令行中。
4. 运行以下命令，指定包含您要使用 IAP 保护的应用的项目。

   gcloud config set project PROJECT_ID

5. 如需启用 IAP，请运行以下命令。

   gcloud iap web enable --resource-type=app-engine --versions=version

6. 向项目添加应具有“IAP-secured Web 应用 User”角色的主体。

   gcloud projects add-iam-policy-binding PROJECT_ID \
          --member=PRINCIPAL_IDENTIFIER \
          --role=roles/iap.httpsResourceAccessor

   • 将 PROJECT_ID 替换为您的项目 ID。
   • 将 PRINCIPAL_IDENTIFIER 替换为必需的主账号。可以是网域、群组、服务账号或用户类型。例如， user:[e-mail]。

启用 IAP 后，您可以使用 gcloud CLI 通过 IAM 角色 roles/iap.httpsResourceAccessor 修改 IAP 访问权限政策。详细了解如何管理角色和权限。

API

1. Run the following command to prepare a settings.json file.

   cat << EOF > settings.json
   {
   "iap":
     {
       "enabled":true
     }
   }
   EOF
   

2. Run the following command to enable IAP.

   curl -X PATCH \
   -H "Authorization: Bearer $(gcloud auth print-access-token)" \
   -H "Accept: application/json" \
   -H "Content-Type: application/json" \
   -d @settings.json \
   "https://appengine.googleapis.com/v1/apps/PROJECT_ID?updateMask=iap"
   

After you enable IAP, you can use the Google Cloud CLI to modify the IAP access policy using the IAM role roles/iap.httpsResourceAccessor. Learn more about managing roles and permissions.

You can enable IAP on a App Engine service within your project. To make some services publicly accessible and require authentication for others, you can use different access levels across services. To learn more, see Manage access with IAP. To make services publicly accessible, grant the IAP-secured Web App User role to allAuthenticatedUsers.

Role-based access: Only principals with the IAP-secured Web App User (roles/iap.httpsResourceAccessor) role on this project are given access. Access to IAP-protected applications is not automatically granted, even to roles with extensive permissions, such as Owner or Editor.

Test user authentication

1. After the role is granted, principals can access the app by authenticating with IAP. Access the app URL from a Google Account that was granted the IAP-secured Web App User (roles/iap.httpsResourceAccessor) role.

2. To test access, open an Incognito window in Chrome, access the app URL, and sign in when prompted. Users who are granted the IAP-secured Web App User (roles/iap.httpsResourceAccessor) role and have successfully authenticated can access the app. Users who aren't granted the required role or fail to authenticate cannot access the app.