Class: Merb::Rack::AbstractAdapter

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

Direct Known Subclasses

Ebb, Mongrel, Thin, WEBrick

Class Method Summary (collapse)

Class Method Details

+ (Object) exit_process(status = 0)

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.



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# File 'merb-core/lib/merb-core/rack/adapter/abstract.rb', line 306

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

+ (Object) new_server(port)

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 start method.

Raises:

  • (NotImplemented)

Overridable:



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# File 'merb-core/lib/merb-core/rack/adapter/abstract.rb', line 67

def self.new_server(port)
  raise NotImplemented
end

+ (Object) process_title(whoami, port)

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.



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# File 'merb-core/lib/merb-core/rack/adapter/abstract.rb', line 317

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

+ (Object) spawn_worker(port)

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.



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# File 'merb-core/lib/merb-core/rack/adapter/abstract.rb', line 89

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

+ (Object) start(opts = {})

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.

Options Hash (opts):

  • :socket (#to_i)

    the socket to bind to

  • :port (#to_i)

    the port to bind to

  • :cluster (Numeric)

    the number



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# File 'merb-core/lib/merb-core/rack/adapter/abstract.rb', line 121

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

+ (Object) start_at_port(port, opts = @opts)

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.



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# File 'merb-core/lib/merb-core/rack/adapter/abstract.rb', line 217

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

+ (Object) start_server

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)

Overridable:



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

def self.start_server
  raise NotImplemented
end

+ (Boolean) stop(status)

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

Raises:

  • (NotImplemented)

Overridable:



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# File 'merb-core/lib/merb-core/rack/adapter/abstract.rb', line 80

def self.stop(status)
  raise NotImplemented
end