feat: Add Task Queue API (#1674)

* Add Task Queue Functions API

entrypoints.json

@@ -24,6 +24,10 @@
     "typings": "./lib/firestore/index.d.ts",
     "dist": "./lib/firestore/index.js"
   },
+  "firebase-admin/functions": {
+    "typings": "./lib/functions/index.d.ts",
+    "dist": "./lib/functions/index.js"
+  },
   "firebase-admin/installations": {
     "typings": "./lib/installations/index.d.ts",
     "dist": "./lib/installations/index.js"

etc/firebase-admin.functions.api.md

@@ -0,0 +1,56 @@
+## API Report File for "firebase-admin.functions"
+
+> Do not edit this file. It is a report generated by [API Extractor](https://api-extractor.com/).
+
+```ts
+
+/// <reference types="node" />
+
+import { Agent } from 'http';
+
+// @public
+export interface AbsoluteDelivery {
+    // @alpha (undocumented)
+    scheduleDelaySeconds?: never;
+    scheduleTime?: Date;
+}
+
+// @public
+export interface DelayDelivery {
+    scheduleDelaySeconds?: number;
+    // @alpha (undocumented)
+    scheduleTime?: never;
+}
+
+// @public
+export type DeliverySchedule = DelayDelivery | AbsoluteDelivery;
+
+// @public
+export class Functions {
+    // Warning: (ae-forgotten-export) The symbol "App" needs to be exported by the entry point index.d.ts
+    //
+    // (undocumented)
+    readonly app: App;
+    taskQueue<Args = Record<string, any>>(functionName: string, extensionId?: string): TaskQueue<Args>;
+}
+
+// @public
+export function getFunctions(app?: App): Functions;
+
+// @public
+export type TaskOptions = DeliverySchedule & TaskOptionsExperimental & {
+    dispatchDeadlineSeconds?: number;
+};
+
+// @public
+export interface TaskOptionsExperimental {
+    // @beta
+    uri?: string;
+}
+
+// @public
+export class TaskQueue<Args = Record<string, any>> {
+    enqueue(data: Args, opts?: TaskOptions): Promise<void>;
+}
+
+```

package.json

@@ -80,6 +80,9 @@
       "firestore": [
         "lib/firestore"
       ],
+      "functions": [
+        "lib/functions"
+      ],
       "installations": [
         "lib/installations"
       ],
@@ -132,6 +135,10 @@
       "require": "./lib/firestore/index.js",
       "import": "./lib/esm/firestore/index.js"
     },
+    "./functions": {
+      "require": "./lib/functions/index.js",
+      "import": "./lib/esm/functions/index.js"
+    },
     "./installations": {
       "require": "./lib/installations/index.js",
       "import": "./lib/esm/installations/index.js"

src/app/credential-internal.ts

@@ -33,6 +33,7 @@ const GOOGLE_AUTH_TOKEN_PATH = '/o/oauth2/token';
 const GOOGLE_METADATA_SERVICE_HOST = 'metadata.google.internal';
 const GOOGLE_METADATA_SERVICE_TOKEN_PATH = '/computeMetadata/v1/instance/service-accounts/default/token';
 const GOOGLE_METADATA_SERVICE_PROJECT_ID_PATH = '/computeMetadata/v1/project/project-id';
+const GOOGLE_METADATA_SERVICE_ACCOUNT_ID_PATH = '/computeMetadata/v1/instance/service-accounts/default/email';
 
 const configDir = (() => {
   // Windows has a dedicated low-rights location for apps at ~/Application Data
@@ -197,6 +198,7 @@ export class ComputeEngineCredential implements Credential {
   private readonly httpClient = new HttpClient();
   private readonly httpAgent?: Agent;
   private projectId?: string;
+  private accountId?: string;
 
   constructor(httpAgent?: Agent) {
     this.httpAgent = httpAgent;
@@ -226,6 +228,25 @@ export class ComputeEngineCredential implements Credential {
       });
   }
 
+  public getServiceAccountEmail(): Promise<string> {
+    if (this.accountId) {
+      return Promise.resolve(this.accountId);
+    }
+
+    const request = this.buildRequest(GOOGLE_METADATA_SERVICE_ACCOUNT_ID_PATH);
+    return this.httpClient.send(request)
+      .then((resp) => {
+        this.accountId = resp.text!;
+        return this.accountId;
+      })
+      .catch((err) => {
+        const detail: string = (err instanceof HttpError) ? getDetailFromResponse(err.response) : err.message;
+        throw new FirebaseAppError(
+          AppErrorCodes.INVALID_CREDENTIAL,
+          `Failed to determine service account email: ${detail}`);
+      });
+  }
+
   private buildRequest(urlPath: string): HttpRequestConfig {
     return {
       method: 'GET',