tartar.js

"use strict";

const Tar = require("tar");
const Path = require("path");
const Fs = require("fs");
const Promise = require("bluebird");
const logger = require("./logger");
const defer = require("./util/defer");
const { fork } = require("child_process");

class Tartar {
  constructor() {
    this._max = 3;
    this._workers = {};
    this._count = 0;
    this._busy = 0;
    this._workQ = [];
    process.once("exit", () => {
      this.shutdown();
    });
  }

  shutdown() {
    if (this._count === 0) return;
    for (let id in this._workers) {
      const worker = this._workers[id];
      worker.child.send({ action: "kill" });
    }
  }

  addWorker() {
    if (this._count < this._max) {
      this._count++;
      const id = `${this._count}`;
      const child = fork(Path.join(__dirname, "tarter.js"), [id], { silent: true });
      this._workers[id] = { child, busy: false };
    }
  }

  extract(data) {
    const d = defer();
    this._workQ.push({ defer: d, data });
    process.nextTick(() => this.process());
    return d.promise;
  }

  process() {
    if (this._workQ.length < 1) return;
    if (this._count === this._busy) return;

    this._busy++;
    const workload = this._workQ.shift();
    for (let id in this._workers) {
      const worker = this._workers[id];
      if (!worker.busy) {
        const handler = resp => {
          if (resp.action !== "extract") {
            return worker.child.once("message", handler);
          }
          worker.busy = false;
          this._busy--;
          if (resp.err) {
            workload.defer.reject(new Error(resp.err.message));
          } else {
            workload.defer.resolve(workload.data);
          }
          process.nextTick(() => this.process());
        };
        worker.busy = true;
        worker.child.once("message", handler);
        worker.child.send(workload.data);
        break;
      }
    }
  }
}

module.exports = Tartar;

// const tt = new Tartar();
// tt.addWorker();
// tt
//   .extract({
//     action: "extract",
//     file: Path.resolve("blah.tgz"),
//     strip: 0,
//     strict: true,
//     outDir: Path.resolve("o")
//   })
//   .then(x => {
//     console.log("done", x);
//     process.exit();
//   });

tarter.js

"use strict";

const Tar = require("tar");
const id = process.argv[2];

process.on("message", data => {
  if (data.action === "extract") {
    Tar.x({
      file: data.file,
      strip: data.strip,
      strict: data.strict,
      C: data.outDir
    })
      .catch(err => {
        data.err = {
          message: err.message
        };
      })
      .then(() => {
        data.$ = id;
        process.send(data);
      });
  } else if (data.action === "kill") {
    process.send({ id, action: "bye" });
    process.nextTick(() => process.exit());
  }
});