ci(docs-infra): change AIO preview server stuff to pull builds from CircleCI

Previously, Travis pushed the build artitfacts to the preview server.
This required us to use JWT to secure the POST request from Travis, to
ensure we couldn't receive malicious builds.

JWT has been deprecated and we are moving our builds to CircleCI.

This commit rewrites the TypeScript part of the preview server that
handles converting build artifact into hosted previews of the docs.

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

@@ -3,29 +3,51 @@ import * as fs from 'fs';
 import * as path from 'path';
 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} from '../common/utils';
+import {assertNotMissingOrEmpty, getPrInfoFromDownloadPath} from '../common/utils';
 
 // Classes
 export class BuildCleaner {
+
   // Constructor
-  constructor(protected buildsDir: string, protected repoSlug: string, protected githubToken: string) {
+  constructor(protected buildsDir: string, protected githubOrg: string, protected githubRepo: string,
+              protected githubToken: string, protected downloadsDir: string, protected artifactPath: string) {
     assertNotMissingOrEmpty('buildsDir', buildsDir);
-    assertNotMissingOrEmpty('repoSlug', repoSlug);
+    assertNotMissingOrEmpty('githubOrg', githubOrg);
+    assertNotMissingOrEmpty('githubRepo', githubRepo);
     assertNotMissingOrEmpty('githubToken', githubToken);
+    assertNotMissingOrEmpty('downloadsDir', downloadsDir);
+    assertNotMissingOrEmpty('artifactPath', artifactPath);
   }
 
   // Methods - Public
-  public cleanUp(): Promise<void> {
-    return Promise.all([
-      this.getExistingBuildNumbers(),
-      this.getOpenPrNumbers(),
-    ]).then(([existingBuilds, openPrs]) => this.removeUnnecessaryBuilds(existingBuilds, openPrs));
+  public async cleanUp() {
+    try {
+      this.logger.log('Cleaning up builds and downloads');
+      const openPrs = await this.getOpenPrNumbers();
+      this.logger.log(`Open pull requests: ${openPrs.length}`);
+      await Promise.all([
+        this.cleanBuilds(openPrs),
+        this.cleanDownloads(openPrs),
+      ]);
+    } catch (error) {
+      this.logger.error('ERROR:', error);
+    }
   }
 
-  // Methods - Protected
-  protected getExistingBuildNumbers(): Promise<number[]> {
-    return new Promise((resolve, reject) => {
+  public async cleanBuilds(openPrs: number[]) {
+    const existingBuilds = await this.getExistingBuildNumbers();
+    await this.removeUnnecessaryBuilds(existingBuilds, openPrs);
+  }
+
+  public async cleanDownloads(openPrs: number[]) {
+    const existingDownloads = await this.getExistingDownloads();
+    await this.removeUnnecessaryDownloads(existingDownloads, openPrs);
+  }
+
+  public getExistingBuildNumbers() {
+    return new Promise<number[]>((resolve, reject) => {
       fs.readdir(this.buildsDir, (err, files) => {
         if (err) {
           return reject(err);
@@ -41,15 +63,14 @@ export class BuildCleaner {
     });
   }
 
-  protected getOpenPrNumbers(): Promise<number[]> {
-    const githubPullRequests = new GithubPullRequests(this.githubToken, this.repoSlug);
-
-    return githubPullRequests.
-      fetchAll('open').
-      then(prs => prs.map(pr => pr.number));
+  public async getOpenPrNumbers() {
+    const api = new GithubApi(this.githubToken);
+    const githubPullRequests = new GithubPullRequests(api, this.githubOrg, this.githubRepo);
+    const prs = await githubPullRequests.fetchAll('open');
+    return prs.map(pr => pr.number);
   }
 
-  protected removeDir(dir: string) {
+  public removeDir(dir: string) {
     try {
       if (shell.test('-d', dir)) {
         shell.chmod('-R', 'a+w', dir);
@@ -60,11 +81,10 @@ export class BuildCleaner {
     }
   }
 
-  protected removeUnnecessaryBuilds(existingBuildNumbers: number[], openPrNumbers: number[]) {
+  public removeUnnecessaryBuilds(existingBuildNumbers: number[], openPrNumbers: number[]) {
     const toRemove = existingBuildNumbers.filter(num => !openPrNumbers.includes(num));
 
     console.log(`Existing builds: ${existingBuildNumbers.length}`);
-    console.log(`Open pull requests: ${openPrNumbers.length}`);
     console.log(`Removing ${toRemove.length} build(s): ${toRemove.join(', ')}`);
 
     // Try removing public dirs.
@@ -77,4 +97,29 @@ export class BuildCleaner {
       map(num => path.join(this.buildsDir, HIDDEN_DIR_PREFIX + String(num))).
       forEach(dir => this.removeDir(dir));
   }
+
+  public getExistingDownloads() {
+    const artifactFile = path.basename(this.artifactPath);
+    return new Promise<string[]>((resolve, reject) => {
+      fs.readdir(this.downloadsDir, (err, files) => {
+        if (err) {
+          return reject(err);
+        }
+        files = files.filter(file => file.endsWith(artifactFile));
+        resolve(files);
+      });
+    });
+  }
+
+  public removeUnnecessaryDownloads(existingDownloads: string[], openPrNumbers: number[]) {
+    const toRemove = existingDownloads.filter(filePath => {
+      const {pr} = getPrInfoFromDownloadPath(filePath);
+      return !openPrNumbers.includes(pr);
+    });
+
+    console.log(`Existing downloads: ${existingDownloads.length}`);
+    console.log(`Removing ${toRemove.length} download(s): ${toRemove.join(', ')}`);
+
+    toRemove.forEach(filePath => shell.rm(filePath));
+  }
 }