Our company unicorn.rb sample

unicorn.rb

# Sample verbose configuration file for Unicorn (not Rack)
#
# This configuration file documents many features of Unicorn
# that may not be needed for some applications. See
# http://unicorn.bogomips.org/examples/unicorn.conf.minimal.rb
# for a much simpler configuration file.
#
# See http://unicorn.bogomips.org/Unicorn/Configurator.html for complete
# documentation.
app_name = "rename_me"
deploy_to = "/opt/#{app_name}"

current_path = "#{deploy_to}/current"
shared_path = "#{deploy_to}/shared"
shared_bundler_gems_path = "#{shared_path}/bundle"

Unicorn::HttpServer::START_CTX[0] = "#{shared_bundler_gems_path}/ruby/1.8/bin/unicorn_rails"

# Use at least one worker per core if you're on a dedicated server,
# more will usually help for _short_ waits on databases/caches.
worker_processes 2

# Since Unicorn is never exposed to outside clients, it does not need to
# run on the standard HTTP port (80), there is no reason to start Unicorn
# as root unless it's from system init scripts.
# If running the master process as root and the workers as an unprivileged
# user, do this to switch euid/egid in the workers (also chowns logs):
# user "unprivileged_user", "unprivileged_group"

# Help ensure your application will always spawn in the symlinked
# "current" directory that Capistrano sets up.
working_directory current_path # available in 0.94.0+

# listen on both a Unix domain socket and a TCP port,
# we use a shorter backlog for quicker failover when busy
listen "#{current_path}/tmp/sockets/#{app_name}.sock", :backlog => 64
#listen 8081, :tcp_nopush => true

# nuke workers after 30 seconds instead of 60 seconds (the default)
timeout 30

# feel free to point this anywhere accessible on the filesystem
pid "#{shared_path}/pids/unicorn.pid"

# By default, the Unicorn logger will write to stderr.
# Additionally, ome applications/frameworks log to stderr or stdout,
# so prevent them from going to /dev/null when daemonized here:
stderr_path "#{shared_path}/log/unicorn.stderr.log"
stdout_path "#{shared_path}/log/unicorn.stdout.log"

# combine REE with "preload_app true" for memory savings
# http://rubyenterpriseedition.com/faq.html#adapt_apps_for_cow
preload_app true
GC.respond_to?(:copy_on_write_friendly=) and
  GC.copy_on_write_friendly = true

before_fork do |server, worker|
  # the following is highly recomended for Rails + "preload_app true"
  # as there's no need for the master process to hold a connection
  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.connection.disconnect!

  # The following is only recommended for memory/DB-constrained
  # installations.  It is not needed if your system can house
  # twice as many worker_processes as you have configured.
  #
  # # This allows a new master process to incrementally
  # # phase out the old master process with SIGTTOU to avoid a
  # # thundering herd (especially in the "preload_app false" case)
  # # when doing a transparent upgrade.  The last worker spawned
  # # will then kill off the old master process with a SIGQUIT.
   old_pid = "#{server.config[:pid]}.oldbin"
   if old_pid != server.pid
     begin
       sig = (worker.nr + 1) >= server.worker_processes ? :QUIT : :TTOU
       Process.kill(sig, File.read(old_pid).to_i)
     rescue Errno::ENOENT, Errno::ESRCH
     end
   end
  #
  # Throttle the master from forking too quickly by sleeping.  Due
  # to the implementation of standard Unix signal handlers, this
  # helps (but does not completely) prevent identical, repeated signals
  # from being lost when the receiving process is busy.
  # sleep 1
  #log_env(:before_fork, server)
end

after_fork do |server, worker|
  # per-process listener ports for debugging/admin/migrations
  # addr = "127.0.0.1:#{9293 + worker.nr}"
  # server.listen(addr, :tries => -1, :delay => 5, :tcp_nopush => true)

  # the following is *required* for Rails + "preload_app true",
  defined?(ActiveRecord::Base) and
        ActiveRecord::Base.establish_connection

  # if preload_app is true, then you may also want to check and
  # restart any other shared sockets/descriptors such as Memcached,
  # and Redis.  TokyoCabinet file handles are safe to reuse
  # between any number of forked children (assuming your kernel
  # correctly implements pread()/pwrite() system calls)
end

before_exec do |server|
  paths = (ENV["PATH"] || "").split(File::PATH_SEPARATOR) 
  paths.unshift "#{shared_bundler_gems_path}/bin"
  ENV["PATH"] = paths.uniq.join(File::PATH_SEPARATOR)

  ENV['GEM_HOME'] = ENV['GEM_PATH'] = shared_bundler_gems_path
  ENV['BUNDLE_GEMFILE'] = "#{current_path}/Gemfile"
end