feat: deferred client initialization (#359)

This PR includes changes from googleapis/gapic-generator-typescript#317 that will move the asynchronous initialization and authentication from the client constructor to an `initialize()` method. This method will be automatically called when the first RPC call is performed. The client library usage has not changed, there is no need to update any code. If you want to make sure the client is authenticated _before_ the first RPC call, you can do ```js await client.initialize(); ``` manually before calling any client method.
googleapis · Mar 6, 2020 · 518e1b0 · 518e1b0
1 parent 635c543
commit 518e1b0
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Showing 5 changed files with 148 additions and 42 deletions.
diff --git a/packages/google-cloud-texttospeech/src/v1/text_to_speech_client.ts b/packages/google-cloud-texttospeech/src/v1/text_to_speech_client.ts
@@ -40,8 +40,13 @@ export class TextToSpeechClient {
   private _descriptors: Descriptors = {page: {}, stream: {}, longrunning: {}};
   private _innerApiCalls: {[name: string]: Function};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
-  textToSpeechStub: Promise<{[name: string]: Function}>;
+  textToSpeechStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of TextToSpeechClient.
@@ -65,8 +70,6 @@ export class TextToSpeechClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -96,25 +99,28 @@ export class TextToSpeechClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof TextToSpeechClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = gaxGrpc.auth as gax.GoogleAuth;
+    this.auth = this._gaxGrpc.auth as gax.GoogleAuth;
 
     // Determine the client header string.
-    const clientHeader = [`gax/${gaxModule.version}`, `gapic/${version}`];
+    const clientHeader = [`gax/${this._gaxModule.version}`, `gapic/${version}`];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -130,12 +136,12 @@ export class TextToSpeechClient {
       'protos',
       'protos.json'
     );
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ? require('../../protos/protos.json') : nodejsProtoPath
     );
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
       'google.cloud.texttospeech.v1.TextToSpeech',
       gapicConfig as gax.ClientConfig,
       opts.clientConfig || {},
@@ -146,17 +152,35 @@ export class TextToSpeechClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.textToSpeechStub) {
+      return this.textToSpeechStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.texttospeech.v1.TextToSpeech.
-    this.textToSpeechStub = gaxGrpc.createStub(
-      opts.fallback
-        ? (protos as protobuf.Root).lookupService(
+    this.textToSpeechStub = this._gaxGrpc.createStub(
+      this._opts.fallback
+        ? (this._protos as protobuf.Root).lookupService(
             'google.cloud.texttospeech.v1.TextToSpeech'
           )
         : // tslint:disable-next-line no-any
-          (protos as any).google.cloud.texttospeech.v1.TextToSpeech,
-      opts
+          (this._protos as any).google.cloud.texttospeech.v1.TextToSpeech,
+      this._opts
     ) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
@@ -176,9 +200,9 @@ export class TextToSpeechClient {
         }
       );
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
           this._descriptors.stream[methodName] ||
           this._descriptors.longrunning[methodName]
@@ -192,6 +216,8 @@ export class TextToSpeechClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.textToSpeechStub;
   }
 
   /**
@@ -314,6 +340,7 @@ export class TextToSpeechClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.listVoices(request, options, callback);
   }
   synthesizeSpeech(
@@ -392,6 +419,7 @@ export class TextToSpeechClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.synthesizeSpeech(request, options, callback);
   }
 
@@ -401,8 +429,9 @@ export class TextToSpeechClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.textToSpeechStub.then(stub => {
+      return this.textToSpeechStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });

diff --git a/packages/google-cloud-texttospeech/src/v1beta1/text_to_speech_client.ts b/packages/google-cloud-texttospeech/src/v1beta1/text_to_speech_client.ts
@@ -40,8 +40,13 @@ export class TextToSpeechClient {
   private _descriptors: Descriptors = {page: {}, stream: {}, longrunning: {}};
   private _innerApiCalls: {[name: string]: Function};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
-  textToSpeechStub: Promise<{[name: string]: Function}>;
+  textToSpeechStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of TextToSpeechClient.
@@ -65,8 +70,6 @@ export class TextToSpeechClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -96,25 +99,28 @@ export class TextToSpeechClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof TextToSpeechClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = gaxGrpc.auth as gax.GoogleAuth;
+    this.auth = this._gaxGrpc.auth as gax.GoogleAuth;
 
     // Determine the client header string.
-    const clientHeader = [`gax/${gaxModule.version}`, `gapic/${version}`];
+    const clientHeader = [`gax/${this._gaxModule.version}`, `gapic/${version}`];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -130,12 +136,12 @@ export class TextToSpeechClient {
       'protos',
       'protos.json'
     );
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ? require('../../protos/protos.json') : nodejsProtoPath
     );
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
       'google.cloud.texttospeech.v1beta1.TextToSpeech',
       gapicConfig as gax.ClientConfig,
       opts.clientConfig || {},
@@ -146,17 +152,35 @@ export class TextToSpeechClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.textToSpeechStub) {
+      return this.textToSpeechStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.texttospeech.v1beta1.TextToSpeech.
-    this.textToSpeechStub = gaxGrpc.createStub(
-      opts.fallback
-        ? (protos as protobuf.Root).lookupService(
+    this.textToSpeechStub = this._gaxGrpc.createStub(
+      this._opts.fallback
+        ? (this._protos as protobuf.Root).lookupService(
             'google.cloud.texttospeech.v1beta1.TextToSpeech'
           )
         : // tslint:disable-next-line no-any
-          (protos as any).google.cloud.texttospeech.v1beta1.TextToSpeech,
-      opts
+          (this._protos as any).google.cloud.texttospeech.v1beta1.TextToSpeech,
+      this._opts
     ) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
@@ -176,9 +200,9 @@ export class TextToSpeechClient {
         }
       );
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
           this._descriptors.stream[methodName] ||
           this._descriptors.longrunning[methodName]
@@ -192,6 +216,8 @@ export class TextToSpeechClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.textToSpeechStub;
   }
 
   /**
@@ -322,6 +348,7 @@ export class TextToSpeechClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.listVoices(request, options, callback);
   }
   synthesizeSpeech(
@@ -400,6 +427,7 @@ export class TextToSpeechClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.synthesizeSpeech(request, options, callback);
   }
 
@@ -409,8 +437,9 @@ export class TextToSpeechClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.textToSpeechStub.then(stub => {
+      return this.textToSpeechStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });