Gluttonous: Really Simple Git Deployment with Vlad

Really Simple Git Deployment with Vlad

kev — Sat, 05 Apr 2008 19:13:00 -0500

Just drop this in your Rakefile. This is slightly modified from something I’m using in production.

Disect! Enjoy! Explanation (read: spoilers) after the jump.

##############################################################################
# Deploy
##############################################################################

begin
  require 'rake_remote_task'

  APP_NAME = "someapp"
  DEPLOY_ROOT = "/usr/local/share/applications/#{APP_NAME}"
  ON_DEPLOY_RESTART = ["someappd"]

  role :app_server, "myserver.com"

  def archive
    commit = `git-rev-list --max-count=1 --abbrev=10 --abbrev-commit HEAD`.chomp
    file = "#{APP_NAME}-#{commit}.tar.gz"
  end

  def restart_daemons
    ON_DEPLOY_RESTART.each do |app|
      run "sudo god restart #{app}"
    end
  end

  namespace :deploy do
    task :build do
      sh "git archive --format=tar HEAD | gzip > #{archive}"
    end

    remote_task :push => :build do
      rsync archive, "/tmp"
    end

    desc "Install a release from the latest commit"
    remote_task :install => :push do
      date_stamp = Time.now.strftime("%Y%m%d")
      last_release = run("ls #{DEPLOY_ROOT}/rels | sort -r | head -n 1").chomp

      if last_release =~ /#{date_stamp}\-(\d+)/
        serial = $1.to_i + 1
      else
        serial = 0 
      end

      rel = ("%d-%02d" % [date_stamp, serial])
      rel_dir = "#{DEPLOY_ROOT}/rels/#{rel}"

      run "sudo mkdir -p #{rel_dir}"
      run "sudo tar -xzvf /tmp/#{archive} -C #{rel_dir} && rm -rf /tmp/#{archive}"
      run "sudo ln -s -f -T #{rel_dir} #{DEPLOY_ROOT}/current"
      restart_daemons
    end

    desc "Rollback to the previous release"
    remote_task :rollback do
      current_link = run("ls -alF #{DEPLOY_ROOT} | awk '/current -> .*/ { print $NF }'").chomp
      current = File.basename(current_link)
      releases = run("ls #{DEPLOY_ROOT}/rels | sort -r").split("\n")
      previous = releases.find {|rel| current > rel}
      raise "No previous release" if previous.nil?
      run "sudo ln -s -f -T #{DEPLOY_ROOT}/rels/#{previous} #{DEPLOY_ROOT}/current"
      restart_daemons
      puts "Moved to #{previous}"
    end

    desc "Rollforward to the next release"
    remote_task :rollforward do
      current_link = run("ls -alF #{DEPLOY_ROOT} | awk '/current -> .*/ { print $NF }'").chomp
      current = File.basename(current_link)
      releases = run("ls #{DEPLOY_ROOT}/rels | sort -r").split("\n")
      next_rel = releases.find {|rel| current < rel}
      raise "No next release" if next_rel.nil?
      run "sudo ln -s -f -T #{DEPLOY_ROOT}/rels/#{next_rel} #{DEPLOY_ROOT}/current"
      restart_daemons
      puts "Moved to #{next_rel}"
    end
  end
rescue LoadError => e
  puts "NOTE: Install vlad to get Kevin's awesome deployment tasks"
end

"Really Simple Git Deployment with Vlad" by Kevin Clark

Fri, 18 Apr 2008 14:05:08 -0400

Hi Tim, The difference is in the magic. Mine doesn’t have any. Maybe I’m just a curmudgeon, but I like understanding what my code is doing. Your code looks like a rake task, but there’s actually lots more going on. That’s great. It’s really powerful and a good choice for many, but frankly I find it obscure and confusing.

I think that fact that my tasks are specifically defined as something other than a normal rake task is a feature. I think that the only code that’s being executed I can’t see are methods I’m explicitly calling is a feature. Most importantly, I think the fact that I’m doing deploy, but just as easily could be doing other remote tasks, clearly, without understanding how a framework works, is a feature. In a technical sense, mine is the less complex code, if not in the number of lines sense.

Just consider that I’ve replaced your framework with a couple of helpers and some version logic. After that, I can hide code however I’d like.

"Really Simple Git Deployment with Vlad" by Tim Dysinger

Thu, 17 Apr 2008 21:50:14 -0400

Sorry but how is that simple? Here’s the capistrano version:

set :application, "website" 
set :scm, :git
set :ssh_options, { :forward_agent => true }
set :repository, "git@github.com:user/#{application}.git" 
set :repository_cache, "git-cache" 
set :deploy_via, :remote_cache

role :web, "dev.server.com" 
role :app, "dev.server.com" 
role :db,  "dev.server.com", :primary => true

namespace :deploy do
  task :start, :roles => :app do
    deploy.mongrel.start
  end

  task :stop, :roles => :app do
    deploy.mongrel.stop
  end

  task :restart, :roles => :app, :except => { :no_release => true } do
    deploy.mongrel.restart
  end

  namespace :mongrel do
    [ :stop, :start, :restart ].each do |t|
      task t, :roles => :app do
        run "umask 02 && cd #{current_path} && mongrel_rails cluster::#{t}" 
      end
    end
  end
end

"Really Simple Git Deployment with Vlad" by Kevin Clark

Sun, 06 Apr 2008 17:55:37 -0400

@Sebastian: I don’t see why not. You might need to tweak it slightly to restart the right services. If you’re doing Rails apps Vlad’s built in recipes may do the job for you as well.

"Really Simple Git Deployment with Vlad" by Sebastian

Sun, 06 Apr 2008 14:42:21 -0400

can I use it with Ror 1.2 ?