Class: Merb::Rack::AbstractAdapter

Inherits:
Object
  • Object
show all
Defined in:
lib/merb-core/rack/adapter/abstract.rb

Direct Known Subclasses

Ebb, Mongrel, Thin, WEBrick

Class Method Summary collapse

Class Method Details

.exit_process(status = 0) ⇒ Object

Exit the process with the specified status.

Parameters

status<Integer>

The exit code of the process.

:api: private


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# File 'lib/merb-core/rack/adapter/abstract.rb', line 314

def self.exit_process(status = 0)
  exit(status)
end

.new_server(port) ⇒ Object

This method is designed to be overridden in a rack adapter. It will be called to create a new instance of the server for the adapter to start. The adapter should attempt to bind to a port at this point. This is called from the AbstractAdapter start method.

Parameters

port<Integer>

The port the server should listen on

:api: plugin

Raises:

  • (NotImplemented)

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# File 'lib/merb-core/rack/adapter/abstract.rb', line 68

def self.new_server(port)
  raise NotImplemented
end

.process_title(whoami, port) ⇒ Object

Set the process title.

Parameters

whoami<Symbol>

Either :spawner for the master process or :worker for any of the worker

processes.
port<Integer>

The base port that the app is running on.

:api: private


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# File 'lib/merb-core/rack/adapter/abstract.rb', line 326

def self.process_title(whoami, port)
  name = Merb::Config[:name]
  app  = "merb#{" : #{name}" if (name && name != "merb")}"
  max_port  = Merb::Config[:cluster] ? (Merb::Config[:cluster] - 1) : 0
  numbers   = ((whoami != :worker) && (max_port > 0)) ? "#{port}..#{port + max_port}" : port
  file      = Merb::Config[:socket_file] % port if Merb::Config[:socket_file]
  
  listening_on = if Merb::Config[:socket]
    "socket#{'s' if max_port > 0 && whoami != :worker} #{numbers} "\
    "#{file ? file : "#{Merb.log_path}/#{name}.#{port}.sock"}"
  else
    "port#{'s' if max_port > 0 && whoami != :worker} #{port}"
  end
  "#{app} : #{whoami} (#{listening_on})"
end

.spawn_worker(port) ⇒ Object

Spawn a new worker process at a port.

Parameters

port<Integer>

The port to start the worker process on.

:api: private


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# File 'lib/merb-core/rack/adapter/abstract.rb', line 93

def self.spawn_worker(port)
  worker_pid = Kernel.fork

  # If we have a worker_pid, we're in the parent.
  if worker_pid.nil?
    # Seed the random number generator
    Kernel.srand

    # Restart the run_later worker, unless we're in the parent or it's alive.
    Merb::Worker.restart unless Merb::Worker.alive?

    # Spawn the worker
    start_at_port(port, @opts)

    throw(:new_worker)
  end

  @pids[port] = worker_pid
  $WORKERS = @pids.values
end

.start(opts = {}) ⇒ Object

The main start method for bootloaders that support forking. This method launches the adapters which inherit using the new_server and start_server methods. This method should not be overridden in adapters which want to fork.

Parameters

opts<Hash>

A hash of options

socket: the socket to bind to
port: the port to bind to
cluster: the number

:api: private


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# File 'lib/merb-core/rack/adapter/abstract.rb', line 126

def self.start(opts={})
  @opts = opts
  $WORKERS ||= []
  parent = nil

  @pids = {}
  port = (opts[:socket] || opts[:port]).to_i
  max_port = Merb::Config[:cluster] ? Merb::Config[:cluster] - 1 : 0

  # If we only have a single merb, just start it up and dispense with
  # the spawner/worker setup.
  if max_port == 0
    start_at_port(port)
    return
  end

  $0 = process_title(:spawner, port)

  # For each port, spawn a new worker. The parent will continue in
  # the loop, while the worker will throw :new_worker and be booted
  # out of the loop.
  catch(:new_worker) do
    0.upto(max_port) do |i|
      parent = spawn_worker(port + i)
    end
  end

  # If we're in a worker, we're done. Otherwise, we've completed
  # setting up workers and now need to watch them.
  return unless parent

  # For each worker, set up a thread in the spawner to watch it
  0.upto(max_port) do |i|
    Thread.new do
      catch(:new_worker) do
        loop do
          pid, status = @pids[port + i], nil
          poller = Merb::System::PortablePoller.new(pid)
          begin
            i = 0
            loop do                    
              # Watch for the pid to exit.
              _, status = Process.wait2(pid, Process::WNOHANG)
              break if status
              
              if (i % 120 == 0) && Merb::Config[:max_memory] && poller.memory > Merb::Config[:max_memory]
                Process.kill("INT", pid)
                if (Process.kill(0, pid) rescue false)
                  sleep Merb::Config[:hang_time] || 5
                  Process.kill(9, pid)
                  Process.wait2(pid) if (Process.kill(0, pid) rescue false)
                end
                
                status = Struct.new(:exitstatus).new(nil)
                break
              end
              i += 1
              sleep 0.25
            end

            # If the pid doesn't exist, we want to silently exit instead of
            # raising here.
          rescue SystemCallError => e
          ensure
            # If there was no worker with that PID, the status was non-0
            # (we send back a status of 128 when ABRT is called on a 
            # worker, and Merb.fatal! exits with a status of 1), or if
            # Merb is in the process of exiting, *then* don't respawn.
            # Note that processes killed with kill -9 will return no
            # exitstatus, and we respawn them.
            if !status || 
              (status.exitstatus && status.exitstatus != 0) || 
              Merb.exiting then
              Thread.exit
            end
          end

          # Otherwise, respawn the worker, and watch it again.
          spawn_worker(port + i)
        end
      end
    end
  end

  # The spawner process will make it here, and when it does, it should just 
  # sleep so it can pick up ctrl-c if it's in console mode.
  sleep

end

.start_at_port(port, opts = @opts) ⇒ Object

Fork a server on the specified port and start the app.

Parameters

port<Integer>

The port to start the server on

opts<Hash>

The hash of options, defaults to the @opts

instance variable.

:api: private


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# File 'lib/merb-core/rack/adapter/abstract.rb', line 224

def self.start_at_port(port, opts = @opts)
  at_exit do
    Merb::Server.remove_pid(port)
  end

  # If Merb is daemonized, trap INT. If it's not daemonized,
  # we let the master process' ctrl-c control the cluster
  # of workers.
  if Merb::Config[:daemonize]
    Merb.trap('INT') do
      Merb.exiting = true
      stop
      Merb.logger.warn! "Exiting port #{port}\n"
      exit_process
    end
    # If it was not fork_for_class_load, we already set up
    # ctrl-c handlers in the master thread.
  elsif Merb::Config[:fork_for_class_load]
    if Merb::Config[:console_trap]
      Merb::Server.add_irb_trap
    end
  end

  # In daemonized mode or not, support HUPing the process to
  # restart it.
  Merb.trap('HUP') do
    Merb.exiting = true
    stop
    Merb.logger.warn! "Exiting port #{port} on #{Process.pid}\n"
    exit_process
  end

  # ABRTing the process will kill it, and it will not be respawned.
  Merb.trap('ABRT') do
    Merb.exiting = true
    stopped = stop(128)
    Merb.logger.warn! "Exiting port #{port}\n" if stopped
    exit_process(128)
  end

  # Each worker gets its own `ps' name.
  $0 = process_title(:worker, port)

  # Store the PID for this worker
  Merb::Server.store_pid(port)

  Merb::Config[:log_delimiter] = "#{process_title(:worker, port)} ~ "

  Merb.reset_logger!
  Merb.logger.warn!("Starting #{self.name.split("::").last} at port #{port}")

  # If we can't connect to the port, keep trying until we can. Print
  # a warning about this once. Try every 0.25s.
  printed_warning = false
  loop do
    begin
      # Call the adapter's new_server method, which should attempt
      # to bind to a port.
      new_server(port)
    rescue Errno::EADDRINUSE => e
      if Merb::Config[:bind_fail_fatal]
        Merb.fatal! "Could not bind to #{port}. It was already in use", e
      end
      
      unless printed_warning
        Merb.logger.warn! "Port #{port} is in use, " \
          "Waiting for it to become available."
        printed_warning = true
      end

      sleep 0.25
      next
    end
    break
  end

  Merb.logger.warn! "Successfully bound to port #{port}"

  Merb::Server.change_privilege

  # Call the adapter's start_server method.
  start_server
end

.start_serverObject

This method is designed to be overridden in a rack adapter. It will be called to start a server created with the new_server method. This is called from the AbstractAdapter start method.

:api: plugin

Raises:

  • (NotImplemented)

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# File 'lib/merb-core/rack/adapter/abstract.rb', line 54

def self.start_server
  raise NotImplemented
end

.stop(status) ⇒ Object

This method is designed to be overridden in a rack adapter. It will be called to stop the adapter server.

Parameters

status<Integer>

The exit status the adapter should exit with.

Returns

Boolean

True if the server was properly stopped.

:api: plugin

Raises:

  • (NotImplemented)

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# File 'lib/merb-core/rack/adapter/abstract.rb', line 83

def self.stop(status)
  raise NotImplemented
end