ankur-anand

// Channels-driven concurrency with Go
// Code examples from Rob Pike's talk on Google I/O 2012:
// http://www.youtube.com/watch?v=f6kdp27TYZs&feature=youtu.be
//
// Concurrency is the key to designing high performance network services. 
// Go's concurrency primitives (goroutines and channels) provide a simple and efficient means 
// of expressing concurrent execution. In this talk we see how tricky concurrency 
// problems can be solved gracefully with simple Go code.

// (1) Generator: function that returns the channel

ankur-anand

Channels Are Not Enough

... or Why Pipelining Is Not That Easy

Golang Concurrency Patterns for brave and smart.

By @kachayev

Intro

ankur-anand

• Binary Search
• Selection Sort
• Quick Sort (first index)
• Quick Sort (middle index)
• Quick Sort (random index)
• Breadth First Search
• Dijkstra's Algorithm

ankur-anand

var express = require('express');
var cookieParser = require('cookie-parser');
var session = require('express-session');
var flash = require('express-flash');
var handlebars = require('express-handlebars')

var app = express();
var sessionStore = new session.MemoryStore;

// View Engines

ankur-anand

Part 1: Why bubbling is good

We start with the following code

function startListening(server, cb) {
  server.listen(99999, 'localhost', cb)
}

ankur-anand

Post Mortem Debugging in NodeJS in the Light of Promises

Context:

we're discussing how we can safely abort on unhandled rejections and obtain meaningful debugging information. Related reading: https://gist.github.com/misterdjules/2969aa1b5e6440a7e401#file-post-mortem-debugging-with-promises-md.

In particular, we're discussing https://gist.github.com/misterdjules/2969aa1b5e6440a7e401#removing-implicit-trycatch-blocks-from-v8s-promises-implementation

Othe recommended reading: On unhandledRejection https://gist.github.com/benjamingr/0237932cee84712951a2

ankur-anand

Possibly Unhandled Rejection NodeJS Promise Hook

###Unhandled Rejection Tracking

Several promise libraries such as bluebird and when as well as some native promise implementations offer potentially unhandled rejection tracking. This means that the following:

Promise.reject(new Error("err")); // never attach a `catch`

ankur-anand

Promise Error Handling Hooks

Problem

A common desire in web programming is to log any uncaught exceptions back to the server. The typical method for doing this is

window.onerror = (message, url, line, column, error) => {
  // log `error` back to the server
};

ankur-anand

The Ultimate Unit Testing Cheat-sheet

For Mocha, Chai and Sinon

using mocha/chai/sinon for node.js unit-tests? check out my utility: mocha-stirrer to easily reuse test components and mock require dependencies

---

• Sinon Chai
• Chai
• Sinon
• Mocha

ankur-anand

var os = require("os");

//Create function to get CPU information
function cpuAverage() {

  //Initialise sum of idle and time of cores and fetch CPU info
  var totalIdle = 0, totalTick = 0;
  var cpus = os.cpus();

  //Loop through CPU cores