vlad snippets

How to use Vlad the Deployer with git, nginx, mongrel, mongrel_cluster and Rails

Tagged vlad, deployer, deploy, capistrano, nginx, mongrel, mongrel_cluster  Languages ruby

This is a draft...

Installing Vlad the Deployer

gem install vlad

Configuring Vlad the Deployer

Add this to the end of RakeFile:

  require 'rubygems'
  require 'vlad'
  Vlad.load :scm => :git
rescue LoadError => e
  puts "Unable to load Vlad #{e}."

Note that we're telling Vlad to use git. This snippet gives you a quick introduction on how to use git with Rails.

Creating the deployment recipe

If you're uncertain what these variables mean, have a look at the docs. This folder is also worth a look, and don't forget to take a peek at the vlad source code.

# General configuration
set :ssh_flags,             '-p 666'
set :application,           'xxx.com'
set :domain,                '127.0.01'
set :deploy_to,             '/var/www/xxx.com'
set :repository,            '/var/lib/git/repositories/xxx.com/.git/'

# Mongrel configuration
set :mongrel_clean,         true
set :mongrel_command,       'sudo mongrel_rails'
set :mongrel_group,         'www-data'
set :mongrel_port,          9000
set :mongrel_servers,       3

#set :mongrel_address,       ''
#set(:mongrel_conf)          { '#{shared_path}/mongrel_cluster.conf' }
#set :mongrel_config_script, nil
#set :mongrel_environment,   'production'
#set :mongrel_log_file,      nil
#set :mongrel_pid_file,      nil
#set :mongrel_prefix,        nil
#set :mongrel_user,          'mongrel'

# Customize Vlad to our needs
namespace :vlad do
  # Add an after_update hook
  remote_task :update do

  # The after_update hook, which is run after vlad:update
  remote_task :after_update do
  # Link to shared resources, if you have them in .gitignore
  #  run "ln -s #{deploy_to}/shared/system/database.yml #{deploy_to}/current/config/database.yml"

  # Deploys a new version of your application
  remote_task :deploy => [:update, :migrate, :start_app]

Setup the server

$ rake vlad:setup

This will create the necessary folders and mongrel_cluster configuration file.

Deploy the application

Now deploy the application with vlad:deploy, which is a custom rake task that we added to the deployment recipe:

$ rake vlad:deploy

Copying your SSH public key to the remote server

Vlad uses ssh for executing commands on the remotely, and rsync for copying the build to your server, which means you'll quickly grow tired of typing your password each time a command is run.

This problem is solved by copying your public SSH keys to the remote server, this snippet explains how to do exactly that.

"updating paths is incompatible with switching branches/forcing" error when using git branches with Vlad

Tagged vlad, git, branch, deploy, revisions, tags  Languages 

I ended up writing this snippet after I found out that deploying a git branch with vlad wasn't as easy as it should've been...

I assumed the Vlad documentation was right, so I put the branch name in the revision variable (located in config/deploy.rb):

set :revision,              'branch_name'

But then I got this error when executing rake vlad:deploy:

git checkout: updating paths is incompatible with switching branches/forcing
Did you intend to checkout 'branch_name' which can not be resolved as commit?

I managed to solve the problem by using the SHA1 hash of the branch instead of the branch name, but that only worked for the current revision:

set :revision,              'd34360870be6536992e6d45bb0aa72eca31e14443'

So after some googling I found this post at scie.nti.st, which made my day because it has the following examples of how to deploy tags and branches with git and Vlad:

# Deploy the latest code, this the default
set :revision, "HEAD" 

# Deploy branch "origin/branch_name"
set :revision, "origin/branch_name"
# Deploy tag "1.0"
set :revision, "1.0"

Note that you have to push the branch to the remote server before running rake vlad:deploy:

git push origin branch_name

Vlad deployment recipe for Phusion Passenger

Tagged vlad, phusion, passenger, apache, deployment  Languages ruby
# General configuration
#set :ssh_flags,             '-p 110000'
set :application,           'app.xxx'
set :domain,                'x.x.x.x'
set :deploy_to,             '/var/www/app.xxx'
set :revision,              'master'
set :repository,            '/var/lib/git/repositories/app.xxx/'

namespace :vlad do
  set :app_command, "/etc/init.d/apache2"
  desc 'Restart Passenger'
  remote_task :start_app, :roles => :app do
    run "touch #{current_release}/tmp/restart.txt"
  desc 'Restarts the apache servers'
  remote_task :start_web, :roles => :app do
    run "sudo #{app_command} restart"

Using thin with Vlad the Deployer

Tagged vlad, thin, git  Languages 

To get Vlad 1.2.0 to work with Thin I did the following.

First change the line where Vlad is included to this:

Vlad.load :scm => :git, :app => :thin

Now run vlad:setup:

$ rake vlad:setup
(in /Users/christian/Documents/Projects/nyhetsanka.fi)
Unable to load Vlad no such file to load -- vlad/thin
rake aborted!
Please specify the server domain via the :domain variable

(See full trace by running task with --trace)

The fix for this error:

Unable to load Vlad no such file to load -- vlad/thin

Is to run the following command:

curl -o /usr/local/lib/ruby/gems/1.8/gems/vlad-1.2.0/lib/vlad/thin.rb http://github.com/dpiddy/vlad/raw/master/lib/vlad/thin.rb