feat!: Improve AuthClient Compatibility

gax/src/fallback.ts

@@ -20,15 +20,7 @@ import * as protobuf from 'protobufjs';
 import * as gax from './gax';
 import * as routingHeader from './routingHeader';
 import {Status} from './status';
-import {
-  GoogleAuth,
-  OAuth2Client,
-  Compute,
-  JWT,
-  UserRefreshClient,
-  GoogleAuthOptions,
-  BaseExternalAccountClient,
-} from 'google-auth-library';
+import {GoogleAuth, AuthClient} from 'google-auth-library';
 import {OperationsClientBuilder} from './operationsClient';
 import type {GrpcClientOptions, ClientStubOptions} from './grpc';
 import {GaxCall, GRPCCall} from './apitypes';
@@ -85,15 +77,8 @@ export interface ServiceMethods {
   [name: string]: protobuf.Method;
 }
 
-export type AuthClient =
-  | OAuth2Client
-  | Compute
-  | JWT
-  | UserRefreshClient
-  | BaseExternalAccountClient;
-
 export class GrpcClient {
-  auth?: OAuth2Client | GoogleAuth;
+  auth?: AuthClient | GoogleAuth;
   authClient?: AuthClient;
   fallback: boolean;
   grpcVersion: string;
@@ -113,33 +98,33 @@ export class GrpcClient {
    * gRPC-fallback version of GrpcClient
    * Implements GrpcClient API for a browser using grpc-fallback protocol (sends serialized protobuf to HTTP/1 $rpc endpoint).
    *
-   * @param {Object=} options.auth - An instance of OAuth2Client to use in browser, or an instance of GoogleAuth from google-auth-library
+   * @param {Object=} options.auth - An instance of AuthClient to use in browser, or an instance of GoogleAuth from google-auth-library
    *  to use in Node.js. Required for browser, optional for Node.js.
    * @constructor
    */
 
   constructor(
-    options: (GrpcClientOptions | {auth: OAuth2Client}) & {
+    options: (GrpcClientOptions | {auth: AuthClient}) & {
       /**
        * Fallback mode to use instead of gRPC.
        * A string is accepted for compatibility, all non-empty string values enable the HTTP REST fallback.
        */
       fallback?: boolean | string;
     } = {}
   ) {
-    if (!isNodeJS()) {
-      if (!options.auth) {
-        throw new Error(
-          JSON.stringify(options) +
-            'You need to pass auth instance to use gRPC-fallback client in browser or other non-Node.js environments. Use OAuth2Client from google-auth-library.'
-        );
-      }
-      this.auth = options.auth as OAuth2Client;
+    if (options.auth) {
+      this.auth = options.auth;
+    } else if ('authClient' in options) {
+      this.auth = options.authClient;
+    } else if (!isNodeJS()) {
+      throw new Error(
+        JSON.stringify(options) +
+          'You need to pass auth instance to use gRPC-fallback client in browser or other non-Node.js environments. Provide a `GoogleAuth` or `AuthClient` instance from `google-auth-library`.'
+      );
     } else {
-      this.auth =
-        (options.auth as GoogleAuth) ||
-        new GoogleAuth(options as GoogleAuthOptions);
+      this.auth = new GoogleAuth(options as GrpcClientOptions);
     }
+
     this.fallback = options.fallback ? true : false;
     this.grpcVersion = require('../../package.json').version;
     this.httpRules = (options as GrpcClientOptions).httpRules;
@@ -264,7 +249,7 @@ export class GrpcClient {
 
   /**
    * gRPC-fallback version of createStub
-   * Creates a gRPC-fallback stub with authentication headers built from supplied OAuth2Client instance
+   * Creates a gRPC-fallback stub with authentication headers built from supplied AuthClient instance
    *
    * @param {function} CreateStub - The constructor function of the stub.
    * @param {Object} service - A protobufjs Service object (as returned by lookupService)

gax/src/fallbackServiceStub.ts

@@ -20,9 +20,9 @@
 import nodeFetch from 'node-fetch';
 import {Response as NodeFetchResponse} from 'node-fetch';
 import {AbortController as NodeAbortController} from 'abort-controller';
+import {AuthClient} from 'google-auth-library';
 
 import {hasWindowFetch, hasAbortController} from './featureDetection';
-import {AuthClient} from './fallback';
 import {StreamArrayParser} from './streamArrayParser';
 import {pipeline, PipelineSource} from 'stream';
 

gax/src/iamService.ts

@@ -20,7 +20,7 @@ import * as gax from './gax';
 import type {GrpcClient, ClientStubOptions} from './grpc';
 import type {GrpcClient as FallbackGrpcClient} from './fallback';
 import {createApiCall} from './createApiCall';
-import {GoogleAuth, OAuth2Client} from 'google-auth-library';
+import {GoogleAuth, AuthClient} from 'google-auth-library';
 import {ProjectIdCallback} from 'google-auth-library/build/src/auth/googleauth';
 import * as routingHeader from './routingHeader';
 import * as gapicConfig from './iam_policy_service_client_config.json';
@@ -40,7 +40,7 @@ export class IamClient {
   private _defaults: {[method: string]: gax.CallSettings};
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   private _protos: any;
-  auth?: GoogleAuth | OAuth2Client;
+  auth?: GoogleAuth | AuthClient;
   descriptors: Descriptors = {page: {}, stream: {}, longrunning: {}};
   innerApiCalls: {[name: string]: Function} = {};
   iamPolicyStub?: Promise<{[name: string]: Function}>;

gax/src/operationsClient.ts

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import type {GoogleAuth, OAuth2Client} from 'google-auth-library';
+import {GoogleAuth, AuthClient} from 'google-auth-library';
 import {ProjectIdCallback} from 'google-auth-library/build/src/auth/googleauth';
 import type {ClientOptions, Callback} from './clientInterface';
 
@@ -62,7 +62,7 @@ export const ALL_SCOPES: string[] = [];
  * @class
  */
 export class OperationsClient {
-  auth?: GoogleAuth | OAuth2Client;
+  auth?: GoogleAuth | AuthClient;
   innerApiCalls: {[name: string]: Function};
   descriptor: {[method: string]: PageDescriptor};
   operationsStub: Promise<{[method: string]: Function}>;

gax/test/unit/regapic.ts

@@ -24,27 +24,12 @@ import * as stream from 'stream';
 import echoProtoJson = require('../fixtures/echo.json');
 import {GrpcClient} from '../../src/fallback';
 import * as transcoding from '../../src/transcoding';
-import {OAuth2Client} from 'google-auth-library';
-import {GrpcClientOptions} from '../../src';
+import {PassThroughClient} from 'google-auth-library';
 import {StreamArrayParser} from '../../src/streamArrayParser';
 
-const authClient = {
-  async getRequestHeaders() {
-    return {Authorization: 'Bearer SOME_TOKEN'};
-  },
-};
-
-const authStub = {
-  async getClient() {
-    return authClient;
-  },
-};
-
 const opts = {
-  auth: authStub,
+  authClient: new PassThroughClient(),
   fallback: 'rest', // enabling REGAPIC
-} as unknown as (GrpcClientOptions | {auth: OAuth2Client}) & {
-  fallback?: boolean | 'rest' | 'proto';
 };
 
 describe('REGAPIC', () => {