wct-sauce/scripts/postinstall.js

WCT plugin that enables support for sauce browsers via Sauce Labs

/**
 * @license
 * Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at
 * http://polymer.github.io/LICENSE.txt The complete set of authors may be found
 * at http://polymer.github.io/AUTHORS.txt The complete set of contributors may
 * be found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by
 * Google as part of the polymer project is also subject to an additional IP
 * rights grant found at http://polymer.github.io/PATENTS.txt
 */
// People frequently sudo install web-component-tester, and we have to be a
// little careful about file permissions.
//
// sauce-connect-launcher downloads and caches the sc binary into its package
// directory the first time you try to connect. If WCT is installed via sudo,
// sauce-connect-launcher will be unable to write to its directory, and fail.
//
// So, we prefetch it during install ourselves.

// Unfortunately, this process runs up against a npm race condition:
// https://github.com/npm/npm/issues/6624
//
// As a workaround, our best bet is to retry with backoff.
function requireSauceConnectLauncher(done, attempt) {
  attempt = attempt || 0;
  var sauceConnectLauncher;
  try {
    sauceConnectLauncher = require('sauce-connect-launcher');
  } catch (error) {
    if (attempt > 3) {
      throw error;
    }
    setTimeout(
        requireSauceConnectLauncher.bind(null, done, attempt + 1),
        Math.pow(2, attempt)  // Exponential backoff to play it safe.
    );
  }
  // All is well.
  done(sauceConnectLauncher);
}

var travis = require('../lib/travis');

// don't download our own sauce connect binary if travis is running the
// sauce_connect addon, or they explicitly opt out via an environment variable
if (!(travis.isTravisSauceConnectRunning() ||
      process.env.SKIP_WCT_SAUCE_POSTINSTALL_DOWNLOAD)) {
  console.log('Prefetching the Sauce Connect binary.');

  requireSauceConnectLauncher(function(sauceConnectLauncher) {
    sauceConnectLauncher.download(
        {
          logger: console.log.bind(console),
        },
        function(error) {
          if (error) {
            console.log('Failed to download sauce connect binary:', error);
            console.log(
                'sauce-connect-launcher will attempt to re-download next time it is run.');
            // We explicitly do not fail the install process if this happens;
            // the user can still recover, unless their permissions are
            // completely screwey.
          }
        });
  });
}