added sample unicorn config

added utility to measure real memory usage
don't require thin by default

Gemfile

@@ -66,7 +66,7 @@ gem 'sinatra', require: nil
 gem 'slim'  # required for sidekiq-web
 gem 'strong_parameters' # remove when we upgrade to Rails 4
 gem 'therubyracer', require: 'v8'
-gem 'thin'
+gem 'thin', require: false
 gem 'diffy', require: false
 gem 'highline', require: false
 
@@ -146,8 +146,8 @@ gem 'rack-mini-profiler', '0.1.27', require: false  # require: false #, git: 'gi
 # https://github.com/jodosha/redis-store/pull/183
 gem 'redis-rack-cache', git: 'https://github.com/SamSaffron/redis-rack-cache.git', require: false
 gem 'rack-cache', require: false
-
 gem 'rack-cors', require: false
+gem 'unicorn', require: false
 
 # perftools only works on 1.9 atm
 group :profile do

Gemfile.lock

@@ -230,6 +230,7 @@ GEM
     json (1.7.7)
     jwt (0.1.8)
       multi_json (>= 1.5)
+    kgio (2.8.0)
     librarian (0.1.0)
       highline
       thor (~> 0.15)
@@ -334,6 +335,7 @@ GEM
       rake (>= 0.8.7)
       rdoc (~> 3.4)
       thor (>= 0.14.6, < 2.0)
+    raindrops (0.11.0)
     rake (10.0.4)
     rake-compiler (0.8.3)
       rake
@@ -455,6 +457,10 @@ GEM
     uglifier (2.0.1)
       execjs (>= 0.3.0)
       multi_json (~> 1.0, >= 1.0.2)
+    unicorn (4.6.3)
+      kgio (~> 2.6)
+      rack
+      raindrops (~> 0.7)
 
 PLATFORMS
   ruby
@@ -549,4 +555,5 @@ DEPENDENCIES
   timecop
   turbo-sprockets-rails3
   uglifier
+  unicorn
   vestal_versions!

config/unicorn.sample.conf.rb

@@ -0,0 +1,80 @@
+# See http://unicorn.bogomips.org/Unicorn/Configurator.html
+
+discourse_path = File.expand_path(File.expand_path(File.dirname(__FILE__)) + "/../")
+
+# tune down if not enough ram
+worker_processes 2
+
+working_directory discourse_path
+
+listen 8080, :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 "#{discourse_path}/tmp/pids/unicorn.pid"
+
+# By default, the Unicorn logger will write to stderr.
+# Additionally, some applications/frameworks log to stderr or stdout,
+# so prevent them from going to /dev/null when daemonized here:
+stderr_path "#{discourse_path}/log/unicorn.stderr.log"
+stdout_path "#{discourse_path}/log/unicorn.stdout.log"
+
+# important for Ruby 2.0
+preload_app true
+
+# Enable this flag to have unicorn test client connections by writing the
+# beginning of the HTTP headers before calling the application.  This
+# prevents calling the application for connections that have disconnected
+# while queued.  This is only guaranteed to detect clients on the same
+# host unicorn runs on, and unlikely to detect disconnects even on a
+# fast LAN.
+check_client_connection false
+
+initialized = false
+before_fork do |server, worker|
+  unless initialized
+    # load up the yaml for the localization bits, in master process
+    I18n.t(:posts)
+    # get rid of rubbish so we don't share it
+    GC.start
+  end
+  ActiveRecord::Base.connection.disconnect!
+  $redis.client.disconnect
+
+
+  #TODO
+  # at this point we want to fork out sidekiq, it will let us reuse the shared memory
+
+  # 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
+end
+
+after_fork do |server, worker|
+  ActiveRecord::Base.establish_connection
+  $redis.client.reconnect
+  Rails.cache.reconnect
+  MessageBus.after_fork
+end

script/memstats.rb

@@ -0,0 +1,136 @@
+#!/usr/bin/env ruby
+# from: https://gist.github.com/kenn/5105061/raw/ac7ebc6be7008c35b72560cc4e05b7cc14eb4919/memstats.rb
+
+#------------------------------------------------------------------------------
+# Aggregate Print useful information from /proc/[pid]/smaps
+#
+# pss  - Roughly the amount of memory that is "really" being used by the pid
+# swap - Amount of swap this process is currently using
+#
+# Reference:
+#  http://www.mjmwired.net/kernel/Documentation/filesystems/proc.txt#361
+#
+# Example:
+#   # ./memstats.rb 4386
+#   Process:             4386
+#   Command Line:        /usr/bin/mongod -f /etc/mongo/mongod.conf
+#   Memory Summary:
+#     private_clean             107,132 kB
+#     private_dirty           2,020,676 kB
+#     pss                     2,127,860 kB
+#     rss                     2,128,536 kB
+#     shared_clean                  728 kB
+#     shared_dirty                    0 kB
+#     size                  149,281,668 kB
+#     swap                    1,719,792 kB
+#------------------------------------------------------------------------------
+
+class Mapping
+  FIELDS = %w[ size rss shared_clean shared_dirty private_clean private_dirty swap pss ]
+  attr_reader :address_start
+  attr_reader :address_end
+  attr_reader :perms
+  attr_reader :offset
+  attr_reader :device_major
+  attr_reader :device_minor
+  attr_reader :inode
+  attr_reader :region
+
+  attr_accessor :size
+  attr_accessor :rss
+  attr_accessor :shared_clean
+  attr_accessor :shared_dirty
+  attr_accessor :private_dirty
+  attr_accessor :private_clean
+  attr_accessor :swap
+  attr_accessor :pss
+
+  def initialize( lines )
+
+    FIELDS.each do |field|
+      self.send("#{field}=", 0)
+    end
+
+    parse_first_line( lines.shift )
+    lines.each do |l|
+      parse_field_line(l)
+    end
+  end
+
+  def parse_first_line( line )
+    parts = line.strip.split
+    @address_start, @address_end = parts[0].split("-")
+    @perms = parts[1]
+    @offset = parts[2]
+    @device_major, @device_minor = parts[3].split(":")
+    @inode = parts[4]
+    @region = parts[5] || "anonymous"
+  end
+
+  def parse_field_line( line )
+    parts = line.strip.split
+    field = parts[0].downcase.sub(':','')
+    if respond_to? "#{field}="
+      value = Float(parts[1]).to_i
+      self.send( "#{field}=", value )
+    end
+  end
+end
+
+def consume_mapping( map_lines, totals )
+  m = Mapping.new( map_lines )
+
+  Mapping::FIELDS.each do |field|
+    totals[field] += m.send( field )
+  end
+  return m
+end
+
+abort 'usage: memstats [pid]' unless ARGV.first
+pid = ARGV.shift.to_i
+totals = Hash.new(0)
+mappings = []
+
+File.open( "/proc/#{pid}/smaps" ) do |smaps|
+
+  map_lines = []
+
+  loop do
+    break if smaps.eof?
+    line = smaps.readline.strip
+    case line
+    when /\w+:\s+/
+      map_lines << line
+    when /[0-9a-f]+:[0-9a-f]+\s+/
+      if map_lines.size > 0 then
+        mappings << consume_mapping( map_lines, totals )
+      end
+      map_lines.clear
+      map_lines << line
+    else
+      break
+    end
+  end
+end
+
+# http://rubyforge.org/snippet/download.php?type=snippet&id=511
+def format_number( n )
+  n.to_s.gsub(/(\d)(?=\d{3}+(?:\.|$))(\d{3}\..*)?/,'\1,\2')
+end
+
+def get_commandline( pid )
+  commandline = IO.read( "/proc/#{pid}/cmdline" ).split("\0")
+  if commandline.first =~ /java$/ then
+    loop { break if commandline.shift == "-jar" }
+    return "[java] #{commandline.shift}"
+  end
+  return commandline.join(' ')
+end
+
+
+puts "#{"Process:".ljust(20)} #{pid}"
+puts "#{"Command Line:".ljust(20)} #{get_commandline(pid)}"
+puts "Memory Summary:"
+totals.keys.sort.each do |k|
+  puts "  #{k.ljust(20)} #{format_number( totals[k] ).rjust(12)} kB"
+end