refactor(docs-infra): use mockable logger (#25671)

Related discussion:
https://github.com/angular/angular/pull/23576#discussion_r187925949.

PR Close #25671

aio/aio-builds-setup/dockerbuild/scripts-js/lib/clean-up/build-cleaner.ts

@@ -5,12 +5,12 @@ import * as shell from 'shelljs';
 import {HIDDEN_DIR_PREFIX} from '../common/constants';
 import {GithubApi} from '../common/github-api';
 import {GithubPullRequests} from '../common/github-pull-requests';
-import {assertNotMissingOrEmpty, createLogger, getPrInfoFromDownloadPath} from '../common/utils';
+import {assertNotMissingOrEmpty, getPrInfoFromDownloadPath, Logger} from '../common/utils';
 
 // Classes
 export class BuildCleaner {
 
-  private logger = createLogger('BuildCleaner');
+  private logger = new Logger('BuildCleaner');
 
   // Constructor
   constructor(protected buildsDir: string, protected githubOrg: string, protected githubRepo: string,

aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/utils.ts

@@ -74,12 +74,25 @@ export const getEnvVar = (name: string, isOptional = false): string => {
   return value || '';
 };
 
-export function createLogger(scope: string) {
-  const padding = ' '.repeat(20 - scope.length);
-  return {
-    error: (...args: any[]) => console.error(`[${new Date()}]`, `${scope}:${padding}`, ...args),
-    info: (...args: any[]) => console.info(`[${new Date()}]`, `${scope}:${padding}`, ...args),
-    log: (...args: any[]) => console.log(`[${new Date()}]`, `${scope}:${padding}`, ...args),
-    warn: (...args: any[]) => console.warn(`[${new Date()}]`, `${scope}:${padding}`, ...args),
-  };
+/**
+ * A basic logger implementation.
+ * Delegates to `console`, but prepends each message with the current date and specified scope (i.e caller).
+ */
+export class Logger {
+  private padding = ' '.repeat(20 - this.scope.length);
+
+  /**
+   * Create a new `Logger` instance for the specified `scope`.
+   * @param scope The logger's scope (added to all messages).
+   */
+  constructor(private scope: string) {}
+
+  public error(...args: any[]) { this.callMethod('error', args); }
+  public info(...args: any[]) { this.callMethod('info', args); }
+  public log(...args: any[]) { this.callMethod('log', args); }
+  public warn(...args: any[]) { this.callMethod('warn', args); }
+
+  private callMethod(method: 'error' | 'info' | 'log' | 'warn', args: any[]) {
+    console[method](`[${new Date()}]`, `${this.scope}:${this.padding}`, ...args);
+  }
 }

aio/aio-builds-setup/dockerbuild/scripts-js/lib/preview-server/build-creator.ts

@@ -5,14 +5,14 @@ import * as fs from 'fs';
 import * as path from 'path';
 import * as shell from 'shelljs';
 import {HIDDEN_DIR_PREFIX} from '../common/constants';
-import {assertNotMissingOrEmpty, computeShortSha, createLogger} from '../common/utils';
+import {assertNotMissingOrEmpty, computeShortSha, Logger} from '../common/utils';
 import {ChangedPrVisibilityEvent, CreatedBuildEvent} from './build-events';
 import {PreviewServerError} from './preview-error';
 
 // Classes
 export class BuildCreator extends EventEmitter {
 
-  private logger = createLogger('BuildCreator');
+  private logger = new Logger('BuildCreator');
 
   // Constructor
   constructor(protected buildsDir: string) {

aio/aio-builds-setup/dockerbuild/scripts-js/lib/preview-server/build-retriever.ts

@@ -4,7 +4,7 @@ import {dirname} from 'path';
 import {mkdir} from 'shelljs';
 import {promisify} from 'util';
 import {CircleCiApi} from '../common/circle-ci-api';
-import {assert, assertNotMissingOrEmpty, computeArtifactDownloadPath, createLogger} from '../common/utils';
+import {assert, assertNotMissingOrEmpty, computeArtifactDownloadPath, Logger} from '../common/utils';
 import {PreviewServerError} from './preview-error';
 
 export interface GithubInfo {
@@ -19,7 +19,7 @@ export interface GithubInfo {
  * A helper that can get information about builds and download build artifacts.
  */
 export class BuildRetriever {
-  private logger = createLogger('BuildRetriever');
+  private logger = new Logger('BuildRetriever');
   constructor(private api: CircleCiApi, private downloadSizeLimit: number, private downloadDir: string) {
     assert(downloadSizeLimit > 0, 'Invalid parameter "downloadSizeLimit" should be a number greater than 0.');
     assertNotMissingOrEmpty('downloadDir', downloadDir);

aio/aio-builds-setup/dockerbuild/scripts-js/lib/preview-server/preview-server-factory.ts

@@ -7,7 +7,7 @@ import {CircleCiApi} from '../common/circle-ci-api';
 import {GithubApi} from '../common/github-api';
 import {GithubPullRequests} from '../common/github-pull-requests';
 import {GithubTeams} from '../common/github-teams';
-import {assert, assertNotMissingOrEmpty, createLogger} from '../common/utils';
+import {assert, assertNotMissingOrEmpty, Logger} from '../common/utils';
 import {BuildCreator} from './build-creator';
 import {ChangedPrVisibilityEvent, CreatedBuildEvent} from './build-events';
 import {BuildRetriever} from './build-retriever';
@@ -32,7 +32,7 @@ export interface PreviewServerConfig {
   trustedPrLabel: string;
 }
 
-const logger = createLogger('PreviewServer');
+const logger = new Logger('PreviewServer');
 
 // Classes
 export class PreviewServerFactory {

aio/aio-builds-setup/dockerbuild/scripts-js/lib/verify-setup/helper.ts

@@ -11,7 +11,7 @@ import {
   AIO_NGINX_PORT_HTTPS,
   AIO_WWW_USER,
 } from '../common/env-variables';
-import {computeShortSha, createLogger} from '../common/utils';
+import {computeShortSha, Logger} from '../common/utils';
 
 // Interfaces - Types
 export interface CmdResult { success: boolean; err: Error | null; stdout: string; stderr: string; }
@@ -31,7 +31,7 @@ class Helper {
     https: AIO_NGINX_PORT_HTTPS,
   };
 
-  private logger = createLogger('TestHelper');
+  private logger = new Logger('TestHelper');
 
   // Constructor
   constructor() {

aio/aio-builds-setup/dockerbuild/scripts-js/lib/verify-setup/mock-external-apis.ts

@@ -2,7 +2,7 @@
 import * as nock from 'nock';
 import * as tar from 'tar-stream';
 import {gzipSync} from 'zlib';
-import {createLogger, getEnvVar} from '../common/utils';
+import {getEnvVar, Logger} from '../common/utils';
 import {BuildNums, PrNums, SHA} from './constants';
 
 // We are using the `nock` library to fake responses from REST requests, when testing.
@@ -14,7 +14,7 @@ import {BuildNums, PrNums, SHA} from './constants';
 // below and return a suitable response. This is quite complicated to setup since the
 // response from, say, CircleCI will affect what request is made to, say, Github.
 
-const logger = createLogger('NOCK');
+const logger = new Logger('mock-external-apis');
 
 const log = (...args: any[]) => {
   // Filter out non-matching URL checks