kibana/tasks/build/downloadNodes.js

module.exports = function (grunt) {
  let { map, fromNode, promisify } = require('bluebird');
  let { resolve } = require('path');
  let { pluck } = require('lodash');
  let { createWriteStream } = require('fs');
  let { createGunzip } = require('zlib');
  let { Extract } = require('tar');

  let mkdirp = promisify(require('mkdirp'));
  let rename = promisify(require('fs').rename);
  let get = (uri) => fromNode(cb => require('wreck').request('GET', uri, null, cb));

  let exists = (path) => fromNode(cb => {
    require('fs').stat(path, err => cb(null, !err));
  });

  let platforms = grunt.config.get('platforms');
  let nodeVersion = grunt.config.get('nodeVersion');
  let baseUri = `https://iojs.org/dist/v${nodeVersion}`;

  let writeTar = async (to, from) => {
    await fromNode(cb => {
      from
      .pipe(createGunzip())
      .on('error', cb)
      .pipe(new Extract({ path: to, strip: 1 }))
      .on('error', cb)
      .on('end', cb);
    });
  };

  let writeExe = async (to, from) => {
    let winBinDir = resolve(to, 'bin');
    await mkdirp(winBinDir);
    await fromNode(cb => {
      from
      .pipe(createWriteStream(resolve(winBinDir, 'node.exe')))
      .on('error', cb)
      .on('finish', cb);
    });
  };

  let run = () => {
    grunt.log.ok(`downloading node binaries`);

    return map(platforms, async function (platform) {
      grunt.file.mkdir(platform.nodeDir);

      let finalDir = resolve(grunt.config.get('root'), platform.nodeDir);
      let downloadDir = `${finalDir}.temp`;

      if (await exists(finalDir)) {
        grunt.log.debug(`${platform} download exists`);
        return;
      }

      let uri;
      if (platform === 'windows') {
        uri = `${baseUri}/win-x64/iojs.exe`;
      } else {
        uri = `${baseUri}/iojs-v${nodeVersion}-${platform}.tar.gz`;
      }

      let resp = await get('GET', uri);
      if (resp.statusCode !== 200) {
        throw new Error(uri + ' failed with a ' + resp.statusCode);
      }

      let write = platform === 'windows' ? writeExe : writeTar;
      await write(downloadDir, resp);
      await rename(downloadDir, finalDir);

      grunt.log.debug(`${platform} download complete`);
    });
  };

  let current = null;
  let start = () => current || (current = run());

  grunt.registerTask('build:downloadNodes:start', start);
  grunt.registerTask('build:downloadNodes:finish', function () {
    start().then(() => {
      grunt.log.ok(`node binaries for ${pluck(platforms, 'name').join(', ')} downloaded`);
    })
    .nodeify(this.async());
  });
};