forwardport configurator fixes from 1.0.2

git-svn-id: svn+ssh://rubyforge.org/var/svn/mongrel/trunk@762 19e92222-5c0b-0410-8929-a290d50e31e9

1 files changed, 388 insertions, 0 deletions

diff --git a/lib/mongrel/configurator.rb b/lib/mongrel/configurator.rb
new file mode 100644
index 0000000..e6b2205
--- /dev/null
+++ b/lib/mongrel/configurator.rb
@@ -0,0 +1,388 @@
+require 'yaml'
+require 'etc'
+
+module Mongrel
+  # Implements a simple DSL for configuring a Mongrel server for your 
+  # purposes.  More used by framework implementers to setup Mongrel
+  # how they like, but could be used by regular folks to add more things
+  # to an existing mongrel configuration.
+  #
+  # It is used like this:
+  #
+  #   require 'mongrel'
+  #   config = Mongrel::Configurator.new :host => "127.0.0.1" do
+  #     listener :port => 3000 do
+  #       uri "/app", :handler => Mongrel::DirHandler.new(".", load_mime_map("mime.yaml"))
+  #     end
+  #     run
+  #   end
+  # 
+  # This will setup a simple DirHandler at the current directory and load additional
+  # mime types from mimy.yaml.  The :host => "127.0.0.1" is actually not 
+  # specific to the servers but just a hash of default parameters that all 
+  # server or uri calls receive.
+  #
+  # When you are inside the block after Mongrel::Configurator.new you can simply
+  # call functions that are part of Configurator (like server, uri, daemonize, etc)
+  # without having to refer to anything else.  You can also call these functions on 
+  # the resulting object directly for additional configuration.
+  #
+  # A major thing about Configurator is that it actually lets you configure 
+  # multiple listeners for any hosts and ports you want.  These are kept in a
+  # map config.listeners so you can get to them.
+  #
+  # * :pid_file => Where to write the process ID.
+  class Configurator
+    attr_reader :listeners
+    attr_reader :defaults
+    attr_reader :needs_restart
+
+    # You pass in initial defaults and then a block to continue configuring.
+    def initialize(defaults={}, &block)
+      @listener = nil
+      @listener_name = nil
+      @listeners = {}
+      @defaults = defaults
+      @needs_restart = false
+      @pid_file = defaults[:pid_file]
+
+      if block
+        cloaker(&block).bind(self).call
+      end
+    end
+
+    # Change privileges of the process to specified user and group.
+    def change_privilege(user, group)
+      begin
+        uid, gid = Process.euid, Process.egid
+        target_uid = Etc.getpwnam(user).uid if user
+        target_gid = Etc.getgrnam(group).gid if group
+
+        if uid != target_uid or gid != target_gid
+          log "Initiating groups for #{user.inspect}:#{group.inspect}."
+          Process.initgroups(user, target_id)
+        
+          log "Changing group to #{group.inspect}."
+          Process::GID.change_privilege(target_gid)
+
+          log "Changing user to #{user.inspect}." 
+          Process::UID.change_privilege(target_uid)
+        end
+      rescue Errno::EPERM => e
+        log "Couldn't change user and group to #{user.inspect}:#{group.inspect}: #{e.to_s}."
+        log "Mongrel failed to start."
+        exit 1
+      end
+    end
+
+    def remove_pid_file
+      File.unlink(@pid_file) if @pid_file and File.exists?(@pid_file)
+    end
+
+    # Writes the PID file if we're not on Windows.
+    def write_pid_file
+      if RUBY_PLATFORM !~ /mswin/
+        log "Writing PID file to #{@pid_file}"
+        open(@pid_file,"w") {|f| f.write(Process.pid) }
+        open(@pid_file,"w") do |f|
+          f.write(Process.pid)
+          File.chmod(0644, @pid_file)
+        end      
+      end
+    end
+
+    # Generates a class for cloaking the current self and making the DSL nicer.
+    def cloaking_class
+      class << self
+        self
+      end
+    end
+
+    # Do not call this.  You were warned.
+    def cloaker(&block)
+      cloaking_class.class_eval do
+        define_method :cloaker_, &block
+        meth = instance_method( :cloaker_ )
+        remove_method :cloaker_
+        meth
+      end
+    end
+
+    # This will resolve the given options against the defaults.
+    # Normally just used internally.
+    def resolve_defaults(options)
+      options.merge(@defaults)
+    end
+
+    # Starts a listener block.  This is the only one that actually takes
+    # a block and then you make Configurator.uri calls in order to setup
+    # your URIs and handlers.  If you write your Handlers as GemPlugins
+    # then you can use load_plugins and plugin to load them.
+    # 
+    # It expects the following options (or defaults):
+    # 
+    # * :host => Host name to bind.
+    # * :port => Port to bind.
+    # * :num_processors => The maximum number of concurrent threads allowed.
+    # * :throttle => Time to pause (in hundredths of a second) between accepting clients. 
+    # * :timeout => Time to wait (in seconds) before killing a stalled thread.
+    # * :user => User to change to, must have :group as well.
+    # * :group => Group to change to, must have :user as well.
+    #
+    def listener(options={},&block)
+      raise "Cannot call listener inside another listener block." if (@listener or @listener_name)
+      ops = resolve_defaults(options)
+      ops[:num_processors] ||= 950
+      ops[:throttle] ||= 0
+      ops[:timeout] ||= 60
+
+      @listener = Mongrel::HttpServer.new(ops[:host], ops[:port].to_i, ops[:num_processors].to_i, ops[:throttle].to_i, ops[:timeout].to_i)
+      @listener_name = "#{ops[:host]}:#{ops[:port]}"
+      @listeners[@listener_name] = @listener
+
+      if ops[:user] and ops[:group]
+        change_privilege(ops[:user], ops[:group])
+      end
+
+      # Does the actual cloaking operation to give the new implicit self.
+      if block
+        cloaker(&block).bind(self).call
+      end
+
+      # all done processing this listener setup, reset implicit variables
+      @listener = nil
+      @listener_name = nil
+    end
+
+
+    # Called inside a Configurator.listener block in order to 
+    # add URI->handler mappings for that listener.  Use this as
+    # many times as you like.  It expects the following options
+    # or defaults:
+    #
+    # * :handler => HttpHandler -- Handler to use for this location.
+    # * :in_front => true/false -- Rather than appending, it prepends this handler.
+    def uri(location, options={})
+      ops = resolve_defaults(options)
+      @listener.register(location, ops[:handler], ops[:in_front])
+    end
+
+
+    # Daemonizes the current Ruby script turning all the
+    # listeners into an actual "server" or detached process.
+    # You must call this *before* frameworks that open files
+    # as otherwise the files will be closed by this function.
+    #
+    # Does not work for Win32 systems (the call is silently ignored).
+    #
+    # Requires the following options or defaults:
+    #
+    # * :cwd => Directory to change to.
+    # * :log_file => Where to write STDOUT and STDERR.
+    # 
+    # It is safe to call this on win32 as it will only require the daemons
+    # gem/library if NOT win32.
+    def daemonize(options={})
+      ops = resolve_defaults(options)
+      # save this for later since daemonize will hose it
+      if RUBY_PLATFORM !~ /mswin/
+        require 'daemons/daemonize'
+
+        logfile = ops[:log_file]
+        if logfile[0].chr != "/"
+          logfile = File.join(ops[:cwd],logfile)
+          if not File.exist?(File.dirname(logfile))
+            log "!!! Log file directory not found at full path #{File.dirname(logfile)}.  Update your configuration to use a full path."
+            exit 1
+          end
+        end
+
+        Daemonize.daemonize(logfile)
+
+        # change back to the original starting directory
+        Dir.chdir(ops[:cwd])
+
+      else
+        log "WARNING: Win32 does not support daemon mode."
+      end
+    end
+
+
+    # Uses the GemPlugin system to easily load plugins based on their
+    # gem dependencies.  You pass in either an :includes => [] or 
+    # :excludes => [] setting listing the names of plugins to include
+    # or exclude from the when determining the dependencies.
+    def load_plugins(options={})
+      ops = resolve_defaults(options)
+
+      load_settings = {}
+      if ops[:includes]
+        ops[:includes].each do |plugin|
+          load_settings[plugin] = GemPlugin::INCLUDE
+        end
+      end
+
+      if ops[:excludes]
+        ops[:excludes].each do |plugin|
+          load_settings[plugin] = GemPlugin::EXCLUDE
+        end
+      end
+
+      GemPlugin::Manager.instance.load(load_settings)
+    end
+
+
+    # Easy way to load a YAML file and apply default settings.
+    def load_yaml(file, default={})
+      default.merge(YAML.load_file(file))
+    end
+
+
+    # Loads the MIME map file and checks that it is correct
+    # on loading.  This is commonly passed to Mongrel::DirHandler
+    # or any framework handler that uses DirHandler to serve files.
+    # You can also include a set of default MIME types as additional
+    # settings.  See Mongrel::DirHandler for how the MIME types map
+    # is organized.
+    def load_mime_map(file, mime={})
+      # configure any requested mime map
+      mime = load_yaml(file, mime)
+
+      # check all the mime types to make sure they are the right format
+      mime.each {|k,v| log "WARNING: MIME type #{k} must start with '.'" if k.index(".") != 0 }
+
+      return mime
+    end
+
+
+    # Loads and creates a plugin for you based on the given
+    # name and configured with the selected options.  The options
+    # are merged with the defaults prior to passing them in.
+    def plugin(name, options={})
+      ops = resolve_defaults(options)
+      GemPlugin::Manager.instance.create(name, ops)
+    end
+
+    # Lets you do redirects easily as described in Mongrel::RedirectHandler.
+    # You use it inside the configurator like this:
+    #
+    #   redirect("/test", "/to/there") # simple
+    #   redirect("/to", /t/, 'w') # regexp
+    #   redirect("/hey", /(w+)/) {|match| ...}  # block
+    #
+    def redirect(from, pattern, replacement = nil, &block)
+      uri from, :handler => Mongrel::RedirectHandler.new(pattern, replacement, &block)
+    end
+
+    # Works like a meta run method which goes through all the 
+    # configured listeners.  Use the Configurator.join method
+    # to prevent Ruby from exiting until each one is done.
+    def run
+      @listeners.each {|name,s| 
+        s.run 
+      }
+
+      $mongrel_sleeper_thread = Thread.new { loop { sleep 1 } }
+    end
+
+    # Calls .stop on all the configured listeners so they
+    # stop processing requests (gracefully).  By default it
+    # assumes that you don't want to restart.
+    def stop(needs_restart=false, synchronous=false)   
+      @listeners.each do |name,s| 
+        s.stop(synchronous)      
+      end      
+      @needs_restart = needs_restart
+    end
+
+
+    # This method should actually be called *outside* of the
+    # Configurator block so that you can control it.  In other words
+    # do it like:  config.join.
+    def join
+      @listeners.values.each {|s| s.acceptor.join }
+    end
+
+
+    # Calling this before you register your URIs to the given location
+    # will setup a set of handlers that log open files, objects, and the
+    # parameters for each request.  This helps you track common problems
+    # found in Rails applications that are either slow or become unresponsive
+    # after a little while.
+    #
+    # You can pass an extra parameter *what* to indicate what you want to 
+    # debug.  For example, if you just want to dump rails stuff then do:
+    #
+    #   debug "/", what = [:rails]
+    # 
+    # And it will only produce the log/mongrel_debug/rails.log file.
+    # Available options are: :access, :files, :objects, :threads, :rails 
+    # 
+    # NOTE: Use [:files] to get accesses dumped to stderr like with WEBrick.
+    def debug(location, what = [:access, :files, :objects, :threads, :rails])
+      require 'mongrel/debug'
+      handlers = {
+        :access => "/handlers/requestlog::access", 
+        :files => "/handlers/requestlog::files", 
+        :objects => "/handlers/requestlog::objects", 
+        :threads => "/handlers/requestlog::threads",
+        :rails => "/handlers/requestlog::params"
+      }
+
+      # turn on the debugging infrastructure, and ObjectTracker is a pig
+      MongrelDbg.configure
+
+      # now we roll through each requested debug type, turn it on and load that plugin
+      what.each do |type| 
+        MongrelDbg.begin_trace type 
+        uri location, :handler => plugin(handlers[type])
+      end
+    end
+
+    # Used to allow you to let users specify their own configurations
+    # inside your Configurator setup.  You pass it a script name and
+    # it reads it in and does an eval on the contents passing in the right
+    # binding so they can put their own Configurator statements.
+    def run_config(script)
+      open(script) {|f| eval(f.read, proc {self}) }
+    end
+
+    # Sets up the standard signal handlers that are used on most Ruby
+    # It only configures if the platform is not win32 and doesn't do
+    # a HUP signal since this is typically framework specific.
+    #
+    # Requires a :pid_file option given to Configurator.new to indicate a file to delete.  
+    # It sets the MongrelConfig.needs_restart attribute if 
+    # the start command should reload.  It's up to you to detect this
+    # and do whatever is needed for a "restart".
+    #
+    # This command is safely ignored if the platform is win32 (with a warning)
+    def setup_signals(options={})
+      ops = resolve_defaults(options)
+
+      # forced shutdown, even if previously restarted (actually just like TERM but for CTRL-C)
+      trap("INT") { log "INT signal received."; stop(false) }
+
+      # clean up the pid file always
+      at_exit { remove_pid_file }
+
+      if RUBY_PLATFORM !~ /mswin/
+        # graceful shutdown
+        trap("TERM") { log "TERM signal received."; stop }
+        trap("USR1") { log "USR1 received, toggling $mongrel_debug_client to #{!$mongrel_debug_client}"; $mongrel_debug_client = !$mongrel_debug_client }
+        # restart
+        trap("USR2") { log "USR2 signal received."; stop(true) }
+
+        log "Signals ready.  TERM => stop.  USR2 => restart.  INT => stop (no restart)."
+      else
+        log "Signals ready.  INT => stop (no restart)."
+      end
+    end
+
+    # Logs a simple message to STDERR (or the mongrel log if in daemon mode).
+    def log(msg)
+      STDERR.print "** ", msg, "\n"
+    end
+
+  end
+end