root/trunk/projects/mongrel_cluster/lib/mongrel_cluster/init.rb

require 'gem_plugin'
require 'mongrel'
require 'yaml'

module Cluster
  module ExecBase
    include Mongrel::Command::Base
      
    STATUS_OK = 0
    STATUS_ERROR = 2
    
    def validate
      valid_exists?(@config_file, "Configuration file does not exist. Run mongrel_rails cluster::configure.")
      @valid
    end
    
    def read_options
      @options = { 
        "environment" => ENV['RAILS_ENV'] || "development",
        "port" => 3000,
        "pid_file" => "tmp/pids/mongrel.pid",
        "log_file" => "log/mongrel.log",
        "servers" => 2
      }
      conf = YAML.load_file(@config_file)
      @options.merge! conf if conf
        
      process_pid_file @options["pid_file"]
      process_log_file @options["log_file"]

      start_port = end_port = @only
      start_port ||=  @options["port"].to_i
      end_port ||=  start_port + @options["servers"] - 1
      @ports = (start_port..end_port).to_a
    end

    def process_pid_file(pid_file)
      @pid_file_ext = File.extname(pid_file)
      @pid_file_base = File.basename(pid_file, @pid_file_ext)
      @pid_file_dir = File.dirname(pid_file)
    end

    def process_log_file(log_file)
      @log_file_ext = File.extname(log_file)
      @log_file_base = File.basename(log_file, @log_file_ext)
      @log_file_dir = File.dirname(log_file)
    end
    
    def port_pid_file(port)
      pid_file = [@pid_file_base, port].join(".") + @pid_file_ext      
      File.join(@pid_file_dir, pid_file)
    end
      
    def port_log_file(port)
      log_file = [@log_file_base, port].join(".") +  @log_file_ext      
      File.join(@log_file_dir, log_file)
    end
      
    def start
      read_options
      
      argv = [ "mongrel_rails" ]
      argv << "start"
      argv << "-d"
      argv << "-e #{@options['environment']}" if @options['environment']
      argv << "-a #{@options['address']}"  if @options['address']
      argv << "-c #{@options['cwd']}" if @options['cwd']
      argv << "-o #{@options['timeout']}" if @options['timeout']
      argv << "-t #{@options['throttle']}" if @options['throttle']
      argv << "-m #{@options['mime_map']}" if @options['mime_map']
      argv << "-r #{@options['docroot']}" if @options['docroot']
      argv << "-n #{@options['num_procs']}" if @options['num_procs']
      argv << "-B" if @options['debug']
      argv << "-S #{@options['config_script']}" if @options['config_script']
      argv << "--user #{@options['user']}" if @options['user']
      argv << "--group #{@options['group']}" if @options['group']
      argv << "--prefix #{@options['prefix']}" if @options['prefix']
      cmd = argv.join " "
      
      @ports.each do |port|              
        if @clean && pid_file_exists?(port) && !check_process(port)
          pid_file = port_pid_file(port)        
          Mongrel.log("missing process: removing #{pid_file}")
          chdir_cwd do
            File.unlink(pid_file) 
          end
        end
        
        if pid_file_exists?(port) && check_process(port)
          Mongrel.log("already started port #{port}")
          next
        end

        exec_cmd = cmd + " -p #{port} -P #{port_pid_file(port)}"
        exec_cmd += " -l #{port_log_file(port)}"
        Mongrel.log("starting port #{port}")
        log_verbose exec_cmd
        output = `#{exec_cmd}`
        Mongrel.log(:error, output) unless $?.success?
      end
    end
      
    def stop
      read_options
    
      argv = [ "mongrel_rails" ]
      argv << "stop"
      argv << "-c #{@options["cwd"]}" if @options["cwd"]
      argv << "-f" if @force
      cmd = argv.join " "

      @ports.each do |port|
        pid = check_process(port)        
        if @clean && pid && !pid_file_exists?(port)       
          Mongrel.log("missing pid_file: killing mongrel_rails port #{port}, pid #{pid}")
          Process.kill("KILL", pid.to_i)  
        end
        
        if !check_process(port)
          Mongrel.log("already stopped port #{port}")
          next       
        end

        exec_cmd = cmd + " -P #{port_pid_file(port)}"
        Mongrel.log("stopping port #{port}")
        log_verbose exec_cmd
        output = `#{exec_cmd}`
        Mongrel.log(:error, output) unless $?.success?
        
      end
    end
  
    def status
      read_options
      
      status = STATUS_OK
     
      @ports.each do |port|
        pid = check_process(port)        
        unless pid_file_exists?(port)        
          Mongrel.log(:error, "missing pid_file: #{port_pid_file(port)}")
          status = STATUS_ERROR
        else
          Mongrel.log("found pid_file: #{port_pid_file(port)}")
        end    
        if pid
          Mongrel.log("found mongrel_rails: port #{port}, pid #{pid}")
        else
          Mongrel.log(:error, "missing mongrel_rails: port #{port}")
          status = STATUS_ERROR
        end
        Mongrel.log("")
      end

      status
    end

    def pid_file_exists?(port)    
      pid_file = port_pid_file(port)
      exists = false
      chdir_cwd do     
        exists = File.exists?(pid_file)  
      end
      exists
    end

    def check_process(port)
      if pid_file_exists?(port)
        pid = read_pid(port)
        ps_output = `ps -o #{cmd_name}= -p #{pid}`
        pid = ps_output =~ /mongrel_rails/ ? pid : nil
      else
        pid = find_pid(port)
      end
      pid
    end 
    
    def cmd_name
      RUBY_PLATFORM =~ /solaris|aix/i ? "args" : "command"
    end
        
    def cmd_flags
      RUBY_PLATFORM =~ /solaris|aix/i ? "-eo" : "-ewwo"
    end
    
    def chdir_cwd
      pwd = Dir.pwd
      Dir.chdir(@options["cwd"]) if @options["cwd"]     
      yield
      Dir.chdir(pwd) if @options["cwd"]
    end

    def read_pid(port)
      pid_file = port_pid_file(port)
      pid = 0
      chdir_cwd do     
        pid = File.read(pid_file)
      end
      pid
    end
 
    def find_pid(port)
      ps_cmd = "ps #{cmd_flags} pid,#{cmd_name}"
      ps_output = `#{ps_cmd}`
      ps_output.each do |line|
        if line =~ /-P #{Regexp.escape(port_pid_file(port))} /
          pid = line.split[0]
          return pid
        end
      end
      nil
    end
    
    def log_verbose(message)
      Mongrel.log(message) if @verbose
    end

  end

  class Start < GemPlugin::Plugin "/commands"
    include ExecBase
    
    def configure
      options [ 
        ['-C', '--config PATH', "Path to cluster configuration file", :@config_file, "config/mongrel_cluster.yml"],
        ['-v', '--verbose', "Print all called commands and output.", :@verbose, false],
        ['', '--clean', "Remove pid_file if needed before starting", :@clean, false],
        ['', '--only PORT', "Port number of cluster member", :@only, nil]
      ]
    end

    def run
      start      
    end
  end
  
  class Stop < GemPlugin::Plugin "/commands"
    include ExecBase

    def configure
      options [
       ['-C', '--config PATH', "Path to cluster configuration file", :@config_file, "config/mongrel_cluster.yml"],
       ['-f', '--force', "Force the shutdown.", :@force, false],
       ['-v', '--verbose', "Print all called commands and output.", :@verbose, false],
       ['', '--clean', "Remove orphaned process if needed before stopping", :@clean, false],
       ['', '--only PORT', "Port number of cluster member", :@only, nil]
      ]
    end
    
    def run
      stop
    end  
  end
  
  class Restart < GemPlugin::Plugin "/commands"
    include ExecBase

    def configure 
      options [ 
        ['-C', '--config PATH', "Path to cluster configuration file", :@config_file, "config/mongrel_cluster.yml"],
        ['-f', '--force', "Force the shutdown.", :@force, false],
        ['-v', '--verbose', "Print all called commands and output.", :@verbose, false],
        ['', '--clean', "Call stop and start with --clean", :@clean, false],        
        ['', '--only PORT', "Port number of cluster member", :@only, nil]       
      ]
    end
    
    def run
      stop
      start
    end
    
  end
  
  class Configure < GemPlugin::Plugin "/commands"
    include ExecBase
    
    def configure 
      options [
        ["-e", "--environment ENV", "Rails environment to run as", :@environment, nil],
        ['-p', '--port PORT', "Starting port to bind to", :@port, 3000],
        ['-a', '--address ADDR', "Address to bind to", :@address, nil],
        ['-l', '--log FILE', "Where to write log messages", :@log_file, "log/mongrel.log"],
        ['-P', '--pid FILE', "Where to write the PID", :@pid_file, "tmp/pids/mongrel.pid"],
        ['-c', '--chdir PATH', "Change to dir before starting (will be expanded)", :@cwd, nil],
        ['-o', '--timeout TIME', "Time to wait (in seconds) before killing a stalled thread", :@timeout, nil],
        ['-t', '--throttle TIME', "Time to pause (in hundredths of a second) between accepting clients", :@throttle, nil],
        ['-m', '--mime PATH', "A YAML file that lists additional MIME types", :@mime_map, nil],
        ['-r', '--root PATH', "Set the document root (default 'public')", :@docroot, nil],
        ['-n', '--num-procs INT', "Number of processor threads to use", :@num_procs, nil],
        ['-B', '--debug', "Enable debugging mode", :@debug, nil],
        ['-S', '--script PATH', "Load the given file as an extra config script.", :@config_script, nil],
        ['-N', '--num-servers INT', "Number of Mongrel servers", :@servers, 2],
        ['-C', '--config PATH', "Path to cluster configuration file", :@config_file, "config/mongrel_cluster.yml"],
        ['', '--user USER', "User to run as", :@user, nil],
        ['', '--group GROUP', "Group to run as", :@group, nil],
        ['', '--prefix PREFIX', "Rails prefix to use", :@prefix, nil]
      ]
    end

    def validate
      @servers = @servers.to_i
      
      valid?(@servers > 0, "Must give a valid number of servers")
      valid_dir? File.dirname(@config_file), "Path to config file not valid: #{@config_file}"
      
      @valid
    end

    def run
      @options = { 
        "port" => @port,
        "servers" => @servers,
        "pid_file" => @pid_file
      }
      
      @options["log_file"] = @log_file if @log_file
      @options["debug"] = @debug if @debug
      @options["num_procs"] = @num_procs if @num_procs
      @options["docroot"] = @docroot if @docroot
      @options["address"] = @address if @address
      @options["timeout"] = @timeout if @timeout
      @options["throttle"] = @throttle if @throttle
      @options["environment"] = @environment if @environment
      @options["mime_map"] = @mime_map if @mime_map
      @options["config_script"] = @config_script if @config_script
      @options["cwd"] = @cwd if @cwd
      @options["user"] = @user if @user
      @options["group"] = @group if @group
      @options["prefix"] = @prefix if @prefix
      
      Mongrel.log("Writing configuration file to #{@config_file}.")
      File.open(@config_file,"w") {|f| f.write(@options.to_yaml)}
    end  
  end

  class Status < GemPlugin::Plugin "/commands"
    include ExecBase

    def configure 
      options [ 
        ['-C', '--config PATH', "Path to cluster configuration file", :@config_file, "config/mongrel_cluster.yml"],
        ['-v', '--verbose', "Print all called commands and output.", :@verbose, false],
        ['', '--only PORT', "Port number of cluster member", :@only, nil]       
      ]
    end
    
    def run
      status
    end

  end
end