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Deploy your projects with zero downtime

22-05-2015

Deploying your project is an important part of our workflow as web developers. There are multiple solutions to this.

Up until now I've been using Laravel Forge. It does more then deployment though, it sets up the server with everything you need (PHP, Nginx, Redis, Postgres, MySQL, Beanstalk) for laravel and general PHP applications.

The deployment part of Laravel Forge is quite simple, it's a push-to-deploy. Push to the branch you specified in Forge and it'll get deployed to your server.

This ok, but while your app is deploying it is not available as Forge needs to update composer dependencies and so on. This is why Taylor Otwell, creator of the Laravel framework and Laravel Forge, created Envoyer.io. The tagline is pretty straightforward: "Zero Downtime PHP Deployment". For this, you'll have to drop another $10 a month (Forge is also $10/mo).

We're going to go over how to do this, for free.

Free alternative, deployer.org

For this we're going to use an opensource package called deployer. This package lets you do the exact same thing as other paid services, but for free and you keep control over your deployments.

Deployer lets you easily create deployments scripts per environment, add custom tasks, run functions and more, all of this with zero downtime of your precious application.

So how does this work ?

Install deployer

You have 2 options on how to install deployer. Either you download the php archive (phar) directly, or you install it globally with composer.

Using deployer.phar

  • Download the deployer.phar file,
  • move to the directory you downlaoded that file,
  • run: mv deployer.phar /usr/local/bin/dep,
  • and finally run: chmod +x /usr/local/bin/dep.

You're good to go.

Using composer

  • Run: composer global require deployer/deployer:~3.0,
  • if you have the composer path in your PATH you're already good to go.

Check the Installation docs on how to update deployer.

Usage

We're now ready to use deployer in our projects. First thing we need to do is add a deploy.php file at the root of our project. This file will be used to setup servers, environments and tasks.

I'm going to assume now that we're on a laravel project, but if you're not, keep reading as this will give you inspiration on how to make this work in your project too.

First thing we need to do is setup our server. You can setup multiple servers, but for this example we'll just go with one.

Setting up server

Setting up a server is easy:

server('staging', 'yoursite.com', 22)
    ->user('forge')
    ->identityFile()
    ->stage('staging')
    ->env('branch', 'develop')
    ->env('deploy_path', '/home/forge/yoursite.com');

As you can see we can name this server (staging), and we give it the host url or ip. ->identityFile() is used to login on our server using or ssh key. Given no arguments this will use the default names: ->identityFile('~/.ssh/id_rsa.pub', '~/.ssh/id_rsa', ''), you can overwrite this by giving those arguments.

As you can see I've also specified which branch to use on the repository we'll use in the next step.

You can also login with a username and password:

->user('name', 'password')

Read more options on how to setup servers on the server documentation page.

Setup your git repository

Next we need to tell deployer which repository to use:

set('repository', 'git@github.com:vendor/yoursite.git');

Deployer will use the branch we site earlier in the server configuration.

Setting up environment file

In laravel we have a .env file which is read by vlucas/phpdotenv package. Since this is not laravel specific your project may quite possibly also use this.

It is important to know how deployer can deploy with zero downtime. What it does is creating 3 folders in the specified folder in the server configuration.

  1. releases: This will contain the latest 3 (by default) releases of your application. A release is created everytime you deploy your application.
  2. current: This is a symlink to the latest release of your application.
  3. shared: This is a folder that's kept in between releases. A storage folder could be placed inside here.

As your .env file is not in version controll how do we create it ? We're going to take advantage of the shared folder. Create a .env file in this shared folder (for this you'll have to deploy at least once), and add all your required environment variables for your project.

Next you're going to create a custom task to add this environment file to the current release.

task('environment', function () {
    run('cp /home/forge/yourwebsite.com/shared/.env {{release_path}}/.env');
})->desc('Environment setup');

This task will copy this .env file from the shared folder to the current release path.

Set writable directories

Next we need to specify which directories are going to be writable:

set('writable_dirs', ['storage', 'vendor']);

Deploy task

And finally we're going to create our deploy task, which is a collection of other tasks.

task('deploy', [
    'deploy:prepare',
    'deploy:release',
    'deploy:update_code',
    'deploy:vendors',
    'deploy:symlink',
    'cleanup',
    'environment',
])->desc('Deploy your project');

To know what each one does, check out the common.php file. This file needs to be included at the start of our deploy.php file.

Putting it all together

This is what our deploy.php file looks like:

<?php

require_once 'recipe/common.php';

set('keep_releases', 5);

server('staging', 'yoursite.com', 22)
    ->user('forge')
    ->identityFile()
    ->stage('staging')
    ->env('branch', 'develop')
    ->env('deploy_path', '/home/forge/yoursite.com');

set('repository', 'git@github.com:vendor/yoursite.git');

/**
 * Setup the environment file in the new release
 */
task('environment', function () {
    run('cp /home/forge/yoursite.com/shared/.env {{release_path}}/.env');
})->desc('Environment setup');

// Laravel writable dirs
set('writable_dirs', ['storage', 'vendor']);

/**
 * Main task
 */
task('deploy', [
    'deploy:prepare',
    'deploy:release',
    'deploy:update_code',
    'deploy:vendors',
    'deploy:symlink',
    'cleanup',
    'environment',
])->desc('Deploy your project');

after('deploy', 'success');

I've added an option to keep the latest 5 releases, this defaults to 3.

Deploy!

You can now run the deployment script using dep deploy staging.

Nginx

Your nginx configuration should be modified sliglty. First you'll need to change the document root to the current directory, which is a symlink to the latest release of your application. For laravel projects this would be current/public

/home/forge/yoursite.com/current/public

Because this is a symlink, you also need to add the following in the server block:

disable_symlinks off;

Nice to haves

If something goes wrong with your latest release simply rollback:

dep rollback staging

Don't trust this yet ? Run the verbose mode to see what will be run on the server:

dep deploy staging -vvv

Optimisation

One caviat of this technique is that creating new release folders will reset realpath cache and opcode cache. One way around this is to add this to your location block in your nginx virtual host:

fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name; 
fastcgi_param DOCUMENT_ROOT $realpath_root;

Todo

To make this even better, we could add the laravel's storage folder on the shared folder, so that we keep our logs (and sessions/cache if you use file based sessions/cache, you shouldn't.)

To do this, it's quite simple:

set('shared_dirs', ['storage']);

The hard part is to change this path for laravel, this is what I haven't figured out yet. In laravel 4 this was a simple configuration file to modify. Though in Laravel 5 we actually need to extend the Application class to overwrite this.

Alternatives

Let me know how you handle your deployments !

I'm available to work on new projects starting August 2018! Get in touch!

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