added clsuter module

Author: AndiDittrich

.eslintrc.json

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+{
+    "extends": ["eslint:recommended", "aenondynamics"]
+}

.gitignore

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+node_modules/*
+.tmp/*
+.hidden/*

.travis.yml

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+language: node_js
+node_js:
+  - "8"
+  - "node"

CHANGES.md

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+### 1.0.0 ###
+Initial Public Release

CONTRIBUTING.md

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+Contribution
+------------
+
+http-magic is OpenSource and managed on [GitHub](https://github.com/) - if you like, you're welcome to contribute!
+To simplify the release and quality control process, please follow these remarks:
+
+### Notices ###
+* Related software packages are updated by the maintainer
+* If you form a concept of **larger project changes**, please [discuss]() them with the contributors **before** implementing

LICENSE.md

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+The MIT License
+
+Copyright (c) 2018 Andi Dittrich
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.

RAEDME.md

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+http-magic
+=========================================
+Summary
+
+![Screenshot](assets/screenshot.png)
+
+## Features ##
+
+
+## Install ##
+
+```bash
+$ npm install http-magic --save
+$ yarn add http-magic
+```
+
+## Usage ##
+
+## Examples ##
+
+## License ##
+http-magic is OpenSource and licensed under the Terms of [The MIT License (X11)](http://opensource.org/licenses/MIT) - your're welcome to contribute

http-magic.js

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+const _cluster = require('./lib/cluster');
+const _webserver = require('./lib/m');
+
+_cluster.init(_webserver);

lib/cluster.js

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+const _cluster = require('cluster');
+const _os = require('os');
+const _logger = require('logging-facility').getLogger('cluster');
+const _workerShutdownTimeout = 5000;
+const _numDefaultWorkers = _os.cpus().length * 2;
+
+function startWorker(){
+    // create a new child process
+    // note: this method RELOADS the entire js file/module! - it is NOT a classical process.fork() !
+    // this allows you to hot-reload your application by restarting the workers
+    return _cluster.fork();
+}
+
+// worker gracefull shutdown
+function stopWorker(worker, cb){
+    // set kill timeout
+    const killTimeout = setTimeout(() => {
+        worker.kill();
+    }, _workerShutdownTimeout);
+
+    // trigger disconnect
+    worker.disconnect();
+
+    // wait for exit + disconnect
+    worker.on('disconnect', () => {
+        // disable kill timer
+        clearTimeout(killTimeout);
+
+        cb(null);
+    });
+}
+
+// hot-restart the cluster without downtime (restart workers in a row)
+function hotReload(cb){
+
+    // get currently active workers
+    const restartList = Object.keys(_cluster.workers);
+
+    // counter of processed workers
+    let numRestartedWorkers = restartList.length;
+
+    // restart each worker
+    restartList.map((workerID) => {
+        // start new child process
+        const newWorker = startWorker();
+
+        // remove old worker when the new one is online!
+        newWorker.once('listening', () => {
+
+            // get worker by id
+            const worker = _cluster.workers[workerID];
+
+            stopWorker(worker, () => {
+                // decrement job finish counter
+                numRestartedWorkers--;
+
+                // all workers restarted ?
+                if (numRestartedWorkers<=0){
+                    cb(null, true);
+                }
+            });
+        })
+    });
+}
+
+// cluster startup
+function initializeCluster(){
+
+    // flag to indicate hot-reloading is active
+    let reloadInProgress = false;
+
+    // num workers set via env ?
+    let numWorkers = parseInt(process.env.workers + '');
+
+    // limit worker threads
+    if (isNaN(numWorkers) || numWorkers < 2 || numWorkers > 50){
+        numWorkers = _numDefaultWorkers;
+    }
+
+    // show num workers
+    _logger.info(`master process ${process.pid} online`);
+    _logger.info(`starting ${numWorkers} workers (default=${_numDefaultWorkers})`);
+
+    // gracefull cluster shutdown
+    process.on('SIGTERM', () => {
+        _logger.info(`graceful shutdown requested by SIGTERM`);
+        _cluster.disconnect(() => {
+            _logger.info(`workers disconnected`);
+            process.exit(0);
+        });
+    });
+
+    // reload event
+    process.on('SIGHUP', () => {
+        _logger.info('hot-reloading requested by SIGHUP');
+
+        // reload active ?
+        if (reloadInProgress === true){
+            _logger.warn('process reload already initialized');
+            return;
+        }
+
+        // set reload flag
+        reloadInProgress = true;
+
+        // trigger reload
+        hotReload(() => {
+            _logger.info('hot-reloading FINISHED');
+            reloadInProgress = false;
+        });
+    });
+
+    // observer workers (all instances)
+    _cluster.on('exit', (worker, code, signal) => {
+        // gracefull shutdown/disconnect ?
+        if (worker.exitedAfterDisconnect === true) {
+            _logger.info(`worker ${worker.process.pid} disconnnected`);
+            return;
+        }
+
+        // log unexpected behaviour
+        _logger.warn(`worker ${worker.process.pid} died - ${code}/${signal} - restarting..`);
+
+        // restart worker
+        startWorker()
+    });
+
+    // observe worker listening events (networking active)
+    _cluster.on('listening', (worker, address) => {
+        _logger.info(`worker ${worker.process.pid} is now connected to ${address.address}:${address.port}`);
+    });
+
+    // spawn n workers
+    for (let i = 0; i<numWorkers ; i++){
+        startWorker();
+    }
+}
+
+module.exports = {
+    init: function(application){
+        // is master process ?
+        if (_cluster.isMaster){
+            initializeCluster();
+
+        // new child process startup
+        }else{
+            application.start();
+        }
+    }
+}

lib/m.js

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+console.log("init module");
+const net = require('net');
+
+module.exports = {
+    start: function(){
+        const server = net.createServer((socket) => {
+            // connections never end
+          });
+        
+          server.listen(8000);
+    }
+}