netj

#!/usr/bin/env bash
# memusg -- Measure memory usage of processes
# Usage: memusg COMMAND [ARGS]...
#
# Author: Jaeho Shin <netj@sparcs.org>
# Created: 2010-08-16
############################################################################
# Copyright 2010 Jaeho Shin.                                               #
#                                                                          #
# Licensed under the Apache License, Version 2.0 (the "License");          #

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

0xjjpa

#Introduction

Developing Chrome Extensions is REALLY fun if you are a Front End engineer. If you, however, struggle with visualizing the architecture of an application, then developing a Chrome Extension is going to bite your butt multiple times due the amount of excessive components the extension works with. Here are some pointers in how to start, what problems I encounter and how to avoid them.

Note: I'm not covering chrome package apps, which although similar, work in a different way. I also won't cover the page options api neither the new brand event pages. What I explain covers most basic chrome applications and should be enough to get you started.

Table of Contents

1. Understand the Chrome Architecture
2. Understand the Tabs-Extension Relationship
3. Picking the right interface for the job

Raynos

Virtual DOM and diffing algorithm

There was a [great article][1] about how react implements it's virtual DOM. There are some really interesting ideas in there but they are deeply buried in the implementation of the React framework.

However, it's possible to implement just the virtual DOM and diff algorithm on it's own as a set of independent modules.

krasnoukhov

My largest Sidekiq application had a memory leak and I was able to find and fix it in just few hours spent on analyzing Ruby's heap. In this post I'll show my profiling setup.

As you might know Ruby 2.1 introduced a few great changes to ObjectSpace, so now it's much easier to find a line of code that is allocating too many objects. Here is great post explaining how it's working.

I was too lazy to set up some seeding and run it locally, so I checked that test suite passes when profiling is enabled and pushed debugging to production. Production environment also suited me better since my jobs data can't be fully random generated.

So, in order to profile your worker, add this to your Sidekiq configuration:

if ENV["PROFILE"]

kevcha

When writing a rails app, we often have to deal with multiple namespaces. The most common case is having classic actions and some others in an admin namespace. Some actions may have same views between namespaces.

For exemple, you could have a ProjectsController with an action index :

class ProjectsController < ApplicationController
  def index
    # do something
  end
end

henrik

defmodule HttpRequester do
  use GenServer

  def start_link(_) do
    GenServer.start_link(__MODULE__, nil, [])
  end

  def fetch(server, url) do
    # Don't use cast: http://blog.elixirsips.com/2014/07/16/errata-dont-use-cast-in-a-poolboy-transaction/
    timeout_ms = 10_000

moklett

# This demonstrates that, when using async/await, a crash in the task will crash the caller
defmodule Tasker do
  def good(message) do
    IO.puts message
  end

  def bad(message) do
    IO.puts message
    raise "I'm BAD!"
  end

cecilemuller

How to setup Let's Encrypt for Nginx on Ubuntu 18.04 (including IPv6, HTTP/2 and A+ SLL rating)

---

Virtual hosts

Let's say you want to host domains first.com and second.com.

Create folders for their files:

andriisoldatenko

Latency Comparison Numbers
--------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD