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

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Exit the process with the specified status.

Parameters

status<Integer>

The exit code of the process.



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# File 'lib/merb-core/rack/adapter/abstract.rb', line 237

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

Raises:

  • (NotImplemented) 


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# File 'lib/merb-core/rack/adapter/abstract.rb', line 25

def self.new_server(port)
  raise NotImplemented
end

.process_title(whoami, port) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

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.



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# File 'lib/merb-core/rack/adapter/abstract.rb', line 249

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]
  
  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

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Spawn a new worker process at a port.

Parameters

port<Integer>

The port to start the worker process on.



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# File 'lib/merb-core/rack/adapter/abstract.rb', line 50

def self.spawn_worker(port)
  worker_pid = Kernel.fork
  start_at_port(port, @opts) unless worker_pid

  # If we have a worker_pid, we're in the parent.
  throw(:new_worker) unless worker_pid

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

.start(opts = {}) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

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



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# File 'lib/merb-core/rack/adapter/abstract.rb', line 73

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 = @pids[port + i]
          begin
            # Watch for the pid to exit.
            _, status = Process.wait2(pid)

            # 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

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

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.



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# File 'lib/merb-core/rack/adapter/abstract.rb', line 152

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

  Merb::Worker.start

  # 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
      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]
    Merb.trap('INT') { 1 }
  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
      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_server ⇒ Object

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.

Raises:

  • (NotImplemented) 


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# File 'lib/merb-core/rack/adapter/abstract.rb', line 11

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.

Raises:

  • (NotImplemented) 


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# File 'lib/merb-core/rack/adapter/abstract.rb', line 40

def self.stop(status)
  raise NotImplemented
end