feat(auth): Enhance non-interactive gcp auth (#4811)

packages/cli/src/utils/sandbox.ts

@@ -525,6 +525,14 @@ export async function start_sandbox(
     );
   }
 
+  // copy GOOGLE_GENAI_USE_GCA
+  if (process.env.GOOGLE_GENAI_USE_GCA) {
+    args.push(
+      '--env',
+      `GOOGLE_GENAI_USE_GCA=${process.env.GOOGLE_GENAI_USE_GCA}`,
+    );
+  }
+
   // copy GOOGLE_CLOUD_PROJECT
   if (process.env.GOOGLE_CLOUD_PROJECT) {
     args.push(

packages/cli/src/validateNonInterActiveAuth.test.ts

@@ -14,6 +14,7 @@ import { AuthType } from '@google/gemini-cli-core';
 describe('validateNonInterActiveAuth', () => {
   let originalEnvGeminiApiKey: string | undefined;
   let originalEnvVertexAi: string | undefined;
+  let originalEnvGcp: string | undefined;
   let consoleErrorSpy: ReturnType<typeof vi.spyOn>;
   let processExitSpy: ReturnType<typeof vi.spyOn>;
   let refreshAuthMock: jest.MockedFunction<
@@ -23,8 +24,10 @@ describe('validateNonInterActiveAuth', () => {
   beforeEach(() => {
     originalEnvGeminiApiKey = process.env.GEMINI_API_KEY;
     originalEnvVertexAi = process.env.GOOGLE_GENAI_USE_VERTEXAI;
+    originalEnvGcp = process.env.GOOGLE_GENAI_USE_GCA;
     delete process.env.GEMINI_API_KEY;
     delete process.env.GOOGLE_GENAI_USE_VERTEXAI;
+    delete process.env.GOOGLE_GENAI_USE_GCA;
     consoleErrorSpy = vi.spyOn(console, 'error').mockImplementation(() => {});
     processExitSpy = vi.spyOn(process, 'exit').mockImplementation((code) => {
       throw new Error(`process.exit(${code}) called`);
@@ -43,6 +46,11 @@ describe('validateNonInterActiveAuth', () => {
     } else {
       delete process.env.GOOGLE_GENAI_USE_VERTEXAI;
     }
+    if (originalEnvGcp !== undefined) {
+      process.env.GOOGLE_GENAI_USE_GCA = originalEnvGcp;
+    } else {
+      delete process.env.GOOGLE_GENAI_USE_GCA;
+    }
     vi.restoreAllMocks();
   });
 
@@ -62,6 +70,15 @@ describe('validateNonInterActiveAuth', () => {
     expect(processExitSpy).toHaveBeenCalledWith(1);
   });
 
+  it('uses LOGIN_WITH_GOOGLE if GOOGLE_GENAI_USE_GCA is set', async () => {
+    process.env.GOOGLE_GENAI_USE_GCA = 'true';
+    const nonInteractiveConfig: NonInteractiveConfig = {
+      refreshAuth: refreshAuthMock,
+    };
+    await validateNonInteractiveAuth(undefined, nonInteractiveConfig);
+    expect(refreshAuthMock).toHaveBeenCalledWith(AuthType.LOGIN_WITH_GOOGLE);
+  });
+
   it('uses USE_GEMINI if GEMINI_API_KEY is set', async () => {
     process.env.GEMINI_API_KEY = 'fake-key';
     const nonInteractiveConfig: NonInteractiveConfig = {
@@ -92,6 +109,19 @@ describe('validateNonInterActiveAuth', () => {
     expect(refreshAuthMock).toHaveBeenCalledWith(AuthType.USE_VERTEX_AI);
   });
 
+  it('uses LOGIN_WITH_GOOGLE if GOOGLE_GENAI_USE_GCA is set, even with other env vars', async () => {
+    process.env.GOOGLE_GENAI_USE_GCA = 'true';
+    process.env.GEMINI_API_KEY = 'fake-key';
+    process.env.GOOGLE_GENAI_USE_VERTEXAI = 'true';
+    process.env.GOOGLE_CLOUD_PROJECT = 'test-project';
+    process.env.GOOGLE_CLOUD_LOCATION = 'us-central1';
+    const nonInteractiveConfig: NonInteractiveConfig = {
+      refreshAuth: refreshAuthMock,
+    };
+    await validateNonInteractiveAuth(undefined, nonInteractiveConfig);
+    expect(refreshAuthMock).toHaveBeenCalledWith(AuthType.LOGIN_WITH_GOOGLE);
+  });
+
   it('uses USE_VERTEX_AI if both GEMINI_API_KEY and GOOGLE_GENAI_USE_VERTEXAI are set', async () => {
     process.env.GEMINI_API_KEY = 'fake-key';
     process.env.GOOGLE_GENAI_USE_VERTEXAI = 'true';

packages/cli/src/validateNonInterActiveAuth.ts

@@ -8,21 +8,28 @@ import { AuthType, Config } from '@google/gemini-cli-core';
 import { USER_SETTINGS_PATH } from './config/settings.js';
 import { validateAuthMethod } from './config/auth.js';
 
+function getAuthTypeFromEnv(): AuthType | undefined {
+  if (process.env.GOOGLE_GENAI_USE_GCA === 'true') {
+    return AuthType.LOGIN_WITH_GOOGLE;
+  }
+  if (process.env.GOOGLE_GENAI_USE_VERTEXAI === 'true') {
+    return AuthType.USE_VERTEX_AI;
+  }
+  if (process.env.GEMINI_API_KEY) {
+    return AuthType.USE_GEMINI;
+  }
+  return undefined;
+}
+
 export async function validateNonInteractiveAuth(
   configuredAuthType: AuthType | undefined,
   nonInteractiveConfig: Config,
 ) {
-  const effectiveAuthType =
-    configuredAuthType ||
-    (process.env.GOOGLE_GENAI_USE_VERTEXAI === 'true'
-      ? AuthType.USE_VERTEX_AI
-      : process.env.GEMINI_API_KEY
-        ? AuthType.USE_GEMINI
-        : undefined);
+  const effectiveAuthType = configuredAuthType || getAuthTypeFromEnv();
 
   if (!effectiveAuthType) {
     console.error(
-      `Please set an Auth method in your ${USER_SETTINGS_PATH} or specify either the GEMINI_API_KEY or GOOGLE_GENAI_USE_VERTEXAI environment variables before running`,
+      `Please set an Auth method in your ${USER_SETTINGS_PATH} or specify one of the following environment variables before running: GEMINI_API_KEY, GOOGLE_GENAI_USE_VERTEXAI, GOOGLE_GENAI_USE_GCA`,
     );
     process.exit(1);
   }

packages/core/src/code_assist/oauth2.test.ts

@@ -57,6 +57,8 @@ describe('oauth2', () => {
     fs.rmSync(tempHomeDir, { recursive: true, force: true });
     vi.clearAllMocks();
     delete process.env.CLOUD_SHELL;
+    delete process.env.GOOGLE_GENAI_USE_GCA;
+    delete process.env.GOOGLE_CLOUD_ACCESS_TOKEN;
   });
 
   it('should perform a web login', async () => {
@@ -332,4 +334,138 @@ describe('oauth2', () => {
       );
     });
   });
+
+  describe('with GCP environment variables', () => {
+    it('should use GOOGLE_CLOUD_ACCESS_TOKEN when GOOGLE_GENAI_USE_GCA is true', async () => {
+      process.env.GOOGLE_GENAI_USE_GCA = 'true';
+      process.env.GOOGLE_CLOUD_ACCESS_TOKEN = 'gcp-access-token';
+
+      const mockSetCredentials = vi.fn();
+      const mockGetAccessToken = vi
+        .fn()
+        .mockResolvedValue({ token: 'gcp-access-token' });
+      const mockOAuth2Client = {
+        setCredentials: mockSetCredentials,
+        getAccessToken: mockGetAccessToken,
+        on: vi.fn(),
+      } as unknown as OAuth2Client;
+      (OAuth2Client as unknown as Mock).mockImplementation(
+        () => mockOAuth2Client,
+      );
+
+      // Mock the UserInfo API response for fetchAndCacheUserInfo
+      (global.fetch as Mock).mockResolvedValue({
+        ok: true,
+        json: vi
+          .fn()
+          .mockResolvedValue({ email: 'test-gcp-account@gmail.com' }),
+      } as unknown as Response);
+
+      const writeFileSpy = vi
+        .spyOn(fs.promises, 'writeFile')
+        .mockResolvedValue(undefined);
+
+      const client = await getOauthClient(
+        AuthType.LOGIN_WITH_GOOGLE,
+        mockConfig,
+      );
+
+      expect(client).toBe(mockOAuth2Client);
+      expect(mockSetCredentials).toHaveBeenCalledWith({
+        access_token: 'gcp-access-token',
+      });
+
+      // Verify fetchAndCacheUserInfo was effectively called
+      expect(mockGetAccessToken).toHaveBeenCalled();
+      expect(global.fetch).toHaveBeenCalledWith(
+        'https://www.googleapis.com/oauth2/v2/userinfo',
+        {
+          headers: {
+            Authorization: 'Bearer gcp-access-token',
+          },
+        },
+      );
+
+      // Verify Google Account was cached
+      const googleAccountPath = path.join(
+        tempHomeDir,
+        '.gemini',
+        'google_accounts.json',
+      );
+      expect(writeFileSpy).toHaveBeenCalledWith(
+        googleAccountPath,
+        JSON.stringify(
+          {
+            active: 'test-gcp-account@gmail.com',
+            old: [],
+          },
+          null,
+          2,
+        ),
+        'utf-8',
+      );
+    });
+
+    it('should not use GCP token if GOOGLE_CLOUD_ACCESS_TOKEN is not set', async () => {
+      process.env.GOOGLE_GENAI_USE_GCA = 'true';
+
+      const mockSetCredentials = vi.fn();
+      const mockGetAccessToken = vi
+        .fn()
+        .mockResolvedValue({ token: 'cached-access-token' });
+      const mockGetTokenInfo = vi.fn().mockResolvedValue({});
+      const mockOAuth2Client = {
+        setCredentials: mockSetCredentials,
+        getAccessToken: mockGetAccessToken,
+        getTokenInfo: mockGetTokenInfo,
+        on: vi.fn(),
+      } as unknown as OAuth2Client;
+      (OAuth2Client as unknown as Mock).mockImplementation(
+        () => mockOAuth2Client,
+      );
+
+      // Make it fall through to cached credentials path
+      const cachedCreds = { refresh_token: 'cached-token' };
+      vi.spyOn(fs.promises, 'readFile').mockResolvedValue(
+        JSON.stringify(cachedCreds),
+      );
+
+      await getOauthClient(AuthType.LOGIN_WITH_GOOGLE, mockConfig);
+
+      // It should be called with the cached credentials, not the GCP access token.
+      expect(mockSetCredentials).toHaveBeenCalledTimes(1);
+      expect(mockSetCredentials).toHaveBeenCalledWith(cachedCreds);
+    });
+
+    it('should not use GCP token if GOOGLE_GENAI_USE_GCA is not set', async () => {
+      process.env.GOOGLE_CLOUD_ACCESS_TOKEN = 'gcp-access-token';
+
+      const mockSetCredentials = vi.fn();
+      const mockGetAccessToken = vi
+        .fn()
+        .mockResolvedValue({ token: 'cached-access-token' });
+      const mockGetTokenInfo = vi.fn().mockResolvedValue({});
+      const mockOAuth2Client = {
+        setCredentials: mockSetCredentials,
+        getAccessToken: mockGetAccessToken,
+        getTokenInfo: mockGetTokenInfo,
+        on: vi.fn(),
+      } as unknown as OAuth2Client;
+      (OAuth2Client as unknown as Mock).mockImplementation(
+        () => mockOAuth2Client,
+      );
+
+      // Make it fall through to cached credentials path
+      const cachedCreds = { refresh_token: 'cached-token' };
+      vi.spyOn(fs.promises, 'readFile').mockResolvedValue(
+        JSON.stringify(cachedCreds),
+      );
+
+      await getOauthClient(AuthType.LOGIN_WITH_GOOGLE, mockConfig);
+
+      // It should be called with the cached credentials, not the GCP access token.
+      expect(mockSetCredentials).toHaveBeenCalledTimes(1);
+      expect(mockSetCredentials).toHaveBeenCalledWith(cachedCreds);
+    });
+  });
 });

packages/core/src/code_assist/oauth2.ts

@@ -78,6 +78,17 @@ export async function getOauthClient(
     },
   });
 
+  if (
+    process.env.GOOGLE_GENAI_USE_GCA &&
+    process.env.GOOGLE_CLOUD_ACCESS_TOKEN
+  ) {
+    client.setCredentials({
+      access_token: process.env.GOOGLE_CLOUD_ACCESS_TOKEN,
+    });
+    await fetchAndCacheUserInfo(client);
+    return client;
+  }
+
   client.on('tokens', async (tokens: Credentials) => {
     await cacheCredentials(tokens);
   });