Tasty Recipes for Capistrano

Sean Cribbs

Chicken Soup for
the Deployed Application

a.k.a. Log analysis

A pinch of tail

task :tail_log, :roles => :app do
  sudo "tail -f #{shared_path}/log/#{rails_env}.log"
end

3T ground syslog

1. Install gem:

   $ sudo gem install -y production_log_analyzer

2. Add to config/environments/production.rb:

   require 'syslog_logger'
   config.logger = SyslogLogger.new("my_app")

3. Add to /etc/syslog.conf

   !my_app *.* /path/to/your/app/shared/log/production.log

Don't grind it yourself!

task :install_syslog_gems, :roles => :app do
  sudo 'gem install -y production_log_analyzer'
end

task :install_syslog_filter, :roles => :app do
  sudo %{echo "!#{application} *.* #{shared_path}/log/#{rails_env}.log" \
>> /etc/syslog.conf}
  sudo "/etc/init.d/sysklogd restart" # works for Ubuntu
end

Stir frequently with logrotate

task :install_log_rotate_script, :roles => :app do
  rotate_script = %Q{#{shared_path}/log/#{rails_env}.log {
  daily
  rotate 14
  size 5M
  compress
  create 640 #{user} #{group}
  missingok
}}
  put rotate_script, "#{shared_path}/logrotate_script"
  sudo "cp #{shared_path}/logrotate_script /etc/logrotate.d/#{application}"
  delete "#{shared_path}/logrotate_script"
end

Rails tastebud:
pl_analyze

set :log_email_recipient, "you@example.com"

task :analyze_logs, :roles => :app do
  sudo %Q{chmod a+r #{shared_path}/log/*.gz}
  run %Q{for file in #{shared_path}/log/*.gz; \
         do gzip -dc "$file" | \
         pl_analyze /dev/stdin -e #{log_email_recipient}; \
         done}
end 

I can't believe it's not syslog

1. Download Hodel3000CompliantLogger
2. Save it to your lib/ directory.
3. Change config/environments/production.rb:

   require 'hodel_3000_compliant_logger'
   config.logger = Hodel3000CompliantLogger.new(config.log_path)

4. No more spurious system messages!

Rake: hard on dirt, soft on hands

set :rake_cmd, (ENV['RAKE_CMD'] || nil)

task :rake_exec do
  if rake_cmd
    run "cd #{current_path} && #{rake} #{rake_cmd} RAILS_ENV=#{rails_env}"
  end
end

Rake: a streak-free shine

# Using database sessions?
task :clear_sessions do
  set :rake_cmd, "db:sessions:clear"
  rake_exec
end

# Clear file-based fragment and/or page cache
task :clear_cache do
  # I usually make a custom Rake task for this
  set :rake_cmd, "tmp:cache:clear" 
  rake_exec
end

Assets Lite, Slow-Churned Style

set :stylesheets, ['reset', 'shared', 'main']
set :javascripts, ['prototype', 'effects', 'application']
task :package_stylesheets, :roles => :web do
  sudo %{rm -f #{current_path}/public/stylesheets/all.css}
  stylesheets.each do |stylesheet|
    run %{cat #{current_path}/public/stylesheets/#{stylesheet}.css >> \
          #{current_path}/public/stylesheets/all.css}
  end
end
task :package_javascripts, :roles => :web do
  sudo %{rm -f #{current_path}/public/javascripts/all.js}
  javascripts.each do |javascript|
    run %{/usr/bin/ruby #{current_path}/lib/jsmin.rb < \
          #{current_path}/public/javascripts/#{javascript}.js >> \
          #{current_path}/public/javascripts/all.js}
  end
end

Nouveau cuisine

• Automate your web server config
• Restart the whole server or individual services
• Dump/backup your database
• Move your assets to S3

Chef's specials

• Capistrano: capify.org
• Google group: http://groups.google.com/group/capistrano
• errtheblog.com
• Ezra Z's blog: brainspl.at
• Peepcode.com
• deprec.org