Sachi xuboso

Golang — Understanding channel, buffer, blocking, deadlock and happy groutines.

I was so confused to understand behaviior of Golang channels, buffer, blocking, deadlocking and groutines.

I read Go by Example topics.

Install HomeBrew first

brew update
brew tap caskroom/cask
brew install brew-cask

If you get the error "already installed", follow the instructions to unlink it, then install again:

Update: https://www.cyanhall.com/posts/notes/7.homebrew-cheatsheet/#java

on El Capitan, after installing the brew...

$ brew update
$ brew tap caskroom/cask
$ brew install Caskroom/cask/java

And Java 8 will be installed at /Library/Java/JavaVirtualMachines/jdk1.8.xxx.jdk/

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

How to set up stress-free SSL on an OS X development machine

One of the best ways to reduce complexity (read: stress) in web development is to minimize the differences between your development and production environments. After being frustrated by attempts to unify the approach to SSL on my local machine and in production, I searched for a workflow that would make the protocol invisible to me between all environments.

Most workflows make the following compromises:

Use HTTPS in production but HTTP locally. This is annoying because it makes the environments inconsistent, and the protocol choices leak up into the stack. For example, your web application needs to understand the underlying protocol when using the secure flag for cookies. If you don't get this right, your HTTP development server won't be able to read the cookies it writes, or worse, your HTTPS production server could pass sensitive cookies over an insecure connection.
Use production SSL certificates locally. This is annoying

[alias]
    lg = log --graph --pretty=format:'%C(yellow)%d%Creset %C(cyan)%h%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --date=short --all

This alias is going to generate an output like this:

	package main

	import (
	"context"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"

	var (
	concurrency = 5
	semaChan = make(chan struct{}, concurrency)
	)

	func doWork(item int) {
	semaChan <- struct{}{} // block while full
	go func() {
	defer func() {
	<-semaChan // read releases a slot

	// --- Compiling ---
	$ wget http://download.redis.io/releases/redis-2.8.3.tar.gz
	$ tar xzvf redis-2.8.3.tar.gz
	$ cd redis-2.8.3
	$ make
	$ make install

	// --- or using yum ---
	$ rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
	$ rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm

	# to generate your dhparam.pem file, run in the terminal
	openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048