Saturday, 16 November 2013

Ballroom blitz (1)

I read this interesting article about Dancer2 deployment. I have a lot to learn about Dancer2 deployment so I thought seriously about apply this practice to my sites. However, working on it, I didn't feel so confortable with the techniques applied there, probably because of my habist more than other reasons.
So, at the end, I came to a different solution and I want to describe it here, to clarify it in my head and to demostrate, once more, that timtowtdi.
I will skip the part about the provider subscription, I want to focus just on the technical issues and I don't want to talk about a specific environment. Let us think just about you having a server, anywhere you want, and the Power of Root is in your hands.

Who's the man?

When you're young and stupid you can think that root is enough, because root is powerful, shiny, charming and has a silver armour with gold drawings on it. Uncle Ben died to teach you that with great power comes great responsibility and you're still so stupid to use root and just root, also for pron watching!

Then you grow up and you know that there're three type of users:

  • root: the boss. Period. You don't annoy the boss with stupid deployment issues.
  • human users: they have to log in on your machine and do dirty things. They need a little, walled garden (some guards on the wall, too)
  • application users: they're on the machine just to work. They're strictly linked to the processes they run.
So, you need to start your app deployment and you have to choose a user that will do it. For this issue, after years chasing not-so-writable directories and evoking the sacred chmod sevensevenseven, I chose the easy way: do all using the nginx application user (nginx or www-data, usually). It's not perfect, it's not the cleanest way, it's not the most secure, but it's tidy enough and give you a lot of space to manage things.
From now on, consider yourself logged as nginx. It's home directory will be /var/www.

Where's the man?

Just a small paragraph about directories. If you don't have a strict discipline your system will become a mess. It's its destiny, it's nature. Entropy is part of every job in the universe.
My favourite idea about how to organize different sites on the same machine is to use reverse domain as subdirectories.
So, will go under /var/www/com/evilgenius/mylittlepony and will be /var/www/org/bunny/fluffy.
This way it will be easy to find the site you're looking for and directory names will never be too long. The policy for domain names is also one of the strictest of the computer science, so you'll never have to manage UTF-256 characters or things like that.

Beam me up Scotty!

This article will speak also about the obvious. 
The easiest way to put the code of your webapp on your server is through some versioning system like git. You just have to pick up an account on github or bitbucket and then, after finishing the development, push all you did on a repository. Then, on your webserver, you just have to clone the project and then maintaining that pulling every update you push.
There's a part of me that don't like working this way. The cleanest and most clever way to deploy a software is packing it someway and then installing it on the server. Packing and installing must be done through a clean, sharp and smart suite of scripts tailored on the software you are managing.
This is the old school procedure and as a lot of old school procedure it's still good, but I have to admit that git is easier and perfect for lazy people.
But! Remember! :
  • Think about if you need a private repository. It could be that someone doesn't want that the code of the site is exposed to everyone with a google bar. I know, I know, open is better, open is good, open i what tender kittens wants, but sometimes it's not what YOU want.
  • gitignore is the most important file of your repository. Design it thinking that nothing about your server environment should be in the git repository. For two simple reasons. One: if you have on git something related to an environment it could change the environment configuration on deploy just because on your developement server something is different and making a git pull a disaster. Two: you don't want your production database password written on a public github repository... and probably you don't want it also on a private one, if you don't know all the contributors to your project.
  • Take a branch as the production branch and never touch it before deploy time. When you have to develope a feature branch from production and develope there. On deploy, merge your new branch with production and push. You have to trust in production branch. Every time you go on your server and do "git pull origin production" you have to know exactly what will happen. Nothing, in the most cases, the deploy of something you planned, on the happy release date.
    Again, if you don't trust all your contributors, there're many ways to prohibit people to push on production. Enforce them. Your contributors are not always malicious, but they're still users. They do users' things. Users things are often stupid things. Stop them.
This project about Dancer2 deployment will be quite long. I'm putting in it a lot of random things from my experience. So I stop it now and I put a number on the title. We'll be back, i hope soon.

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