Added convenience controls for FCGI processes (especially when managed remotely): spinner, spawner, and reaper. They reside in script/process. More details can be had by calling them with -h/--help

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1909 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 237 insertions, 0 deletions

diff --git a/railties/bin/process/reaper b/railties/bin/process/reaper
new file mode 100755
index 0000000000..a636d329c8
--- /dev/null
+++ b/railties/bin/process/reaper
@@ -0,0 +1,123 @@
+#!/usr/local/bin/ruby
+
+require 'optparse'
+require 'net/http'
+require 'uri'
+
+def nudge(url, iterations)
+  print "Nudging #{url}: "
+  iterations.times {  Net::HTTP.get_response(URI.parse(url)); print "."; STDOUT.flush }
+  puts
+end
+
+if RUBY_PLATFORM =~ /mswin32/ then abort("Reaper is only for Unix") end
+
+class ProgramProcess
+  class << self
+    def process_keywords(action, *keywords)
+      processes = keywords.collect { |keyword| find_by_keyword(keyword) }.flatten
+
+      if processes.empty?
+        puts "Couldn't find any process matching: #{keywords.join(" or ")}"
+      else
+        processes.each do |process|
+          puts "#{action.capitalize}ing #{process}"
+          process.send(action)
+        end
+      end      
+    end
+
+    def find_by_keyword(keyword)
+      process_lines_with_keyword(keyword).split("\n").collect { |line|
+        next if line.include?("inq") || line.include?("ps -ax") || line.include?("grep")
+        pid, *command = line.split
+        new(pid, command.join(" "))
+      }.compact
+    end
+
+    private
+      def process_lines_with_keyword(keyword)
+        `ps -ax -o 'pid command' | grep #{keyword}`
+      end
+  end
+
+  def initialize(pid, command)
+    @pid, @command = pid, command
+  end
+
+  def find
+  end
+
+  def reload
+    `kill -s HUP #{@pid}`
+  end
+
+  def graceful
+    `kill -s TERM #{@pid}`
+  end
+
+  def kill
+    `kill -9 #{@pid}`
+  end
+
+  def to_s
+    "[#{@pid}] #{@command}"
+  end
+end
+
+OPTIONS = {
+  :action     => "graceful",
+  :dispatcher => File.expand_path(File.dirname(__FILE__) + '/../../public/dispatch.fcgi'),
+  :iterations => 10,
+  :nudge      => false
+}
+
+ARGV.options do |opts|
+  opts.banner = "Usage: reaper [options]"
+
+  opts.separator ""
+
+  opts.on <<-EOF
+  Description:
+    The reaper is used to reload, gracefully exit, and forcefully exit FCGI processes
+    running a Rails Dispatcher. This is commonly done when a new version of the application
+    is available, so the existing processes can be updated to use the latest code.
+
+    The reaper actions are:
+
+    * reload  : Only reloads the application, but not the framework (like the development environment)
+    * graceful: Marks all of the processes for exit after the next request
+    * kill    : Forcefully exists all processes regardless of whether they're currently serving a request
+
+    Graceful exist is the most common and default action. But since the processes won't exist until after
+    their next request, it's often necessary to ensure that such a request occurs right after they've been
+    marked. That's what nudging is for. 
+
+    A nudge is simply a request to a URL where the dispatcher is serving. You should perform one nudge per
+    FCGI process you have running if they're setup in a round-robin. Be sure to do one nudge per FCGI process
+    across all your servers. So three servers with 10 processes each should nudge 30 times to be sure all processes
+    are restarted.
+    
+    NOTE: You're responsible for restarting the processes after they exit. This can be automated by using
+    the spinner.
+  Examples:
+    reaper -a reload
+    reaper -n http://www.example.com -i 10 # gracefully exit, nudge 10 times
+  EOF
+
+  opts.on("  Options:")
+
+  opts.on("-a", "--action=name", "reload|graceful|kill (default: #{OPTIONS[:action]})", String)  { |OPTIONS[:action]| }
+  opts.on("-d", "--dispatcher=path", "default: #{OPTIONS[:dispatcher]}", String)                 { |OPTIONS[:dispatcher]| }
+  opts.on("-n", "--nudge=url", "Should point to URL that's handled by the FCGI process", String) { |OPTIONS[:nudge]| }
+  opts.on("-i", "--iterations=number", "One nudge per FCGI process running (default: #{OPTIONS[:iterations]})", Integer) { |OPTIONS[:iterations]| }
+
+  opts.separator ""
+
+  opts.on("-h", "--help", "Show this help message.") { puts opts; exit }
+
+  opts.parse!
+end
+
+ProgramProcess.process_keywords(OPTIONS[:action], OPTIONS[:dispatcher])
+nudge(OPTIONS[:nudge], OPTIONS[:iterations]) if OPTIONS[:nudge]
\ No newline at end of file
diff --git a/railties/bin/process/spawner b/railties/bin/process/spawner
new file mode 100755
index 0000000000..2ac0df04f8
--- /dev/null
+++ b/railties/bin/process/spawner
@@ -0,0 +1,54 @@
+#!/usr/local/bin/ruby
+
+require 'optparse'
+
+def spawn(port)
+  print "Starting FCGI on port: #{port}\n  "
+  system("#{OPTIONS[:spawner]} -f #{OPTIONS[:dispatcher]} -p #{port}")
+end
+
+OPTIONS = {
+  :environment => "production",
+  :spawner     => '/usr/bin/env spawn-fcgi',
+  :dispatcher  => File.expand_path(File.dirname(__FILE__) + '/../../public/dispatch.fcgi'),
+  :port        => 8000,
+  :instances   => 3
+}
+
+ARGV.options do |opts|
+  opts.banner = "Usage: spawner [options]"
+
+  opts.separator ""
+
+  opts.on <<-EOF
+  Description:
+    The spawner is a wrapper for spawn-fcgi that makes it easier to start multiple FCGI
+    processes running the Rails dispatcher. The spawn-fcgi command is included with the lighttpd 
+    web server, but can be used with both Apache and lighttpd (and any other web server supporting
+    externally managed FCGI processes).
+
+    You decide a starting port (default is 8000) and the number of FCGI process instances you'd 
+    like to run. So if you pick 9100 and 3 instances, you'll start processes on 9100, 9101, and 9102.
+
+  Examples:
+    spawner               # starts instances on 8000, 8001, and 8002
+    spawner -p 9100 -i 10 # starts 10 instances counting from 9100 to 9109
+  EOF
+
+  opts.on("  Options:")
+
+  opts.on("-p", "--port=number", Integer, "Starting port number (default: #{OPTIONS[:port]})")                   { |OPTIONS[:port]| }
+  opts.on("-i", "--instances=number", Integer, "Number of instances (default: #{OPTIONS[:instances]})")          { |OPTIONS[:instances]| }
+  opts.on("-e", "--environment=name", String, "test|development|production (default: #{OPTIONS[:environment]})") { |OPTIONS[:environment]| }
+  opts.on("-s", "--spawner=path",    String, "default: #{OPTIONS[:spawner]}")                                    { |OPTIONS[:spawner]| }
+  opts.on("-d", "--dispatcher=path", String, "default: #{OPTIONS[:dispatcher]}") { |dispatcher| OPTIONS[:dispatcher] = File.expand_path(dispatcher) }
+
+  opts.separator ""
+
+  opts.on("-h", "--help", "Show this help message.") { puts opts; exit }
+
+  opts.parse!
+end
+
+ENV["RAILS_ENV"] = OPTIONS[:environment]
+OPTIONS[:instances].times { |i| spawn(OPTIONS[:port] + i) }
\ No newline at end of file
diff --git a/railties/bin/process/spinner b/railties/bin/process/spinner
new file mode 100755
index 0000000000..ff7a576163
--- /dev/null
+++ b/railties/bin/process/spinner
@@ -0,0 +1,60 @@
+#!/usr/local/bin/ruby
+
+require 'optparse'
+
+def daemonize
+  exit if fork                   # Parent exits, child continues.
+  Process.setsid                 # Become session leader.
+  exit if fork                   # Zap session leader. See [1].
+  Dir.chdir "/"                  # Release old working directory.
+  File.umask 0000                # Ensure sensible umask. Adjust as needed.
+  STDIN.reopen "/dev/null"       # Free file descriptors and
+  STDOUT.reopen "/dev/null", "a" # point them somewhere sensible.
+  STDERR.reopen STDOUT           # STDOUT/ERR should better go to a logfile.
+end
+
+OPTIONS = {
+  :interval   => 1.0,
+  :command    => File.expand_path(File.dirname(__FILE__) + '/spawner'),
+  :daemon     => false
+}
+
+ARGV.options do |opts|
+  opts.banner = "Usage: spinner [options]"
+
+  opts.separator ""
+
+  opts.on <<-EOF
+  Description:
+    The spinner is a protection loop for the spawner, which will attempt to restart any FCGI processes
+    that might have been restarted or outright crashed. It's a brute-force attempt that'll just try
+    to run the spawner every X number of seconds, so it does pose a load on the server (~1% on our test
+    server).    
+
+  Examples:
+    spinner # attempts to run the spawner with default settings every second with output on the terminal
+    spinner -i 3 -d # only run the spawner every 3 seconds and detach from the terminal to become a daemon
+    spinner -c '/path/to/app/script/process/spawner -p 9000 -i 10' -d # using custom spawner
+  EOF
+
+  opts.on("  Options:")
+
+  opts.on("-c", "--command=path",    String) { |OPTIONS[:command]| }
+  opts.on("-i", "--interval=seconds", Float) { |OPTIONS[:interval]| }
+  opts.on("-d", "--daemon")                  { |OPTIONS[:daemon]| }
+
+  opts.separator ""
+
+  opts.on("-h", "--help", "Show this help message.") { puts opts; exit }
+
+  opts.parse!
+end
+
+daemonize if OPTIONS[:daemon]
+
+loop do
+  system(OPTIONS[:command])
+  sleep(OPTIONS[:interval])
+end
+
+trap(OPTIONS[:daemon] ? "TERM" : "INT") { exit }
\ No newline at end of file