feat: support concurrent installation of browsers (#3929)

A few details on locking registry to prohibit concurrent access:
- locking is done by creating a `__dirlock` directory in the top-level
of our registry.
- since `__dirlock` directory does not match any of browser
directories, old versions of the installer will ignore it
- in case of concurrent access, installation will wait for a lock to be
released for 10 minutes, periodically trying to grab the lock. If it
fails to do so in 10 minutes, the installation will fail.

Fixes #3912

Author: aslushnikov

package-lock.json

@@ -43,6 +43,7 @@
     "mime": "^2.4.6",
     "pngjs": "^5.0.0",
     "progress": "^2.0.3",
+    "proper-lockfile": "^4.1.1",
     "proxy-from-env": "^1.1.0",
     "rimraf": "^3.0.2",
     "ws": "^7.3.1"
@@ -55,6 +56,7 @@
     "@types/node": "^10.17.28",
     "@types/pngjs": "^3.4.2",
     "@types/progress": "^2.0.3",
+    "@types/proper-lockfile": "^4.1.1",
     "@types/proxy-from-env": "^1.0.1",
     "@types/rimraf": "^3.0.0",
     "@types/ws": "7.2.6",

package.json

@@ -19,6 +19,7 @@ import * as fs from 'fs';
 import * as path from 'path';
 import * as util from 'util';
 import * as removeFolder from 'rimraf';
+import * as lockfile from 'proper-lockfile';
 import * as browserPaths from '../utils/browserPaths';
 import * as browserFetcher from './browserFetcher';
 import { getFromENV } from '../utils/utils';
@@ -32,16 +33,29 @@ const fsWriteFileAsync = util.promisify(fs.writeFile.bind(fs));
 const removeFolderAsync = util.promisify(removeFolder);
 
 export async function installBrowsersWithProgressBar(packagePath: string) {
-  const browsersPath = browserPaths.browsersPath(packagePath);
-  const linksDir = path.join(browsersPath, '.links');
-
   if (getFromENV('PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD')) {
     browserFetcher.logPolitely('Skipping browsers download because `PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD` env variable is set');
     return false;
   }
+
+  const browsersPath = browserPaths.browsersPath(packagePath);
+  await fsMkdirAsync(browsersPath, { recursive: true });
+  const releaseLock = await lockfile.lock(browsersPath, {
+    retries: {
+      retries: 10,
+      // Retry 20 times during 10 minutes with
+      // exponential back-off.
+      // See documentation at: https://www.npmjs.com/package/retry#retrytimeoutsoptions
+      factor: 1.27579,
+    },
+    lockfilePath: path.join(browsersPath, '__dirlock'),
+  });
+  const linksDir = path.join(browsersPath, '.links');
+
   await fsMkdirAsync(linksDir,  { recursive: true });
   await fsWriteFileAsync(path.join(linksDir, sha1(packagePath)), packagePath);
   await validateCache(packagePath, browsersPath, linksDir);
+  await releaseLock();
 }
 
 async function validateCache(packagePath: string, browsersPath: string, linksDir: string) {