Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Tree: ec83f0f8b8
Fetching contributors…

Cannot retrieve contributors at this time

1549 lines (1445 sloc) 59.173 kB
require 'rubyeventmachine'
require 'em/version'
require 'em/pool'
require 'em/deferrable'
require 'em/future'
require 'em/streamer'
require 'em/spawnable'
require 'em/processes'
require 'em/iterator'
require 'em/buftok'
require 'em/timers'
require 'em/protocols'
require 'em/connection'
require 'em/callback'
require 'em/queue'
require 'em/channel'
require 'em/file_watch'
require 'em/process_watch'
require 'em/tick_loop'
require 'em/resolver'
require 'em/completion'
require 'em/threaded_resource'
require 'shellwords'
require 'thread'
require 'resolv'
# Top-level EventMachine namespace. If you are looking for EventMachine examples, see {file:docs/GettingStarted.md EventMachine tutorial}.
#
# ## Key methods ##
# ### Starting and stopping the event loop ###
#
# * {EventMachine.run}
# * {EventMachine.stop_event_loop}
#
# ### Implementing clients ###
#
# * {EventMachine.connect}
#
# ### Implementing servers ###
#
# * {EventMachine.start_server}
#
# ### Working with timers ###
#
# * {EventMachine.add_timer}
# * {EventMachine.add_periodic_timer}
# * {EventMachine.cancel_timer}
#
# ### Working with blocking tasks ###
#
# * {EventMachine.defer}
# * {EventMachine.next_tick}
#
# ### Efficient proxying ###
#
# * {EventMachine.enable_proxy}
# * {EventMachine.disable_proxy}
module EventMachine
class << self
# Exposed to allow joining on the thread, when run in a multithreaded
# environment. Performing other actions on the thread has undefined
# semantics (read: a dangerous endevor).
#
# @return [Thread]
attr_reader :reactor_thread
end
@next_tick_mutex = Mutex.new
@reactor_running = false
@next_tick_queue = []
@tails = []
@threadpool = nil
# System errnos
# @private
ERRNOS = Errno::constants.grep(/^E/).inject(Hash.new(:unknown)) { |hash, name|
errno = Errno.__send__(:const_get, name)
hash[errno::Errno] = errno
hash
}
# Initializes and runs an event loop. This method only returns if code inside the block passed to this method
# calls {EventMachine.stop_event_loop}. The block is executed after initializing its internal event loop but *before* running the loop,
# therefore this block is the right place to call any code that needs event loop to run, for example, {EventMachine.start_server},
# {EventMachine.connect} or similar methods of libraries that use EventMachine under the hood
# (like `EventMachine::HttpRequest.new` or `AMQP.start`).
#
# Programs that are run for long periods of time (e.g. servers) usually start event loop by calling {EventMachine.run}, and let it
# run "forever". It's also possible to use {EventMachine.run} to make a single client-connection to a remote server,
# process the data flow from that single connection, and then call {EventMachine.stop_event_loop} to stop, in other words,
# to run event loop for a short period of time (necessary to complete some operation) and then shut it down.
#
# Once event loop is running, it is perfectly possible to start multiple servers and clients simultaneously: content-aware
# proxies like [Proxymachine](https://github.com/mojombo/proxymachine) do just that.
#
# ## Using EventMachine with Ruby on Rails and other Web application frameworks ##
#
# Standalone applications often run event loop on the main thread, thus blocking for their entire lifespan. In case of Web applications,
# if you are running an EventMachine-based app server such as [Thin](http://code.macournoyer.com/thin/) or [Goliath](https://github.com/postrank-labs/goliath/),
# they start event loop for you. Servers like Unicorn, Apache Passenger or Mongrel occupy main Ruby thread to serve HTTP(S) requests. This means
# that calling {EventMachine.run} on the same thread is not an option (it will result in Web server never binding to the socket).
# In that case, start event loop in a separate thread as demonstrated below.
#
#
# @example Starting EventMachine event loop in the current thread to run the "Hello, world"-like Echo server example
#
# #!/usr/bin/env ruby
#
# require 'rubygems' # or use Bundler.setup
# require 'eventmachine'
#
# class EchoServer < EM::Connection
# def receive_data(data)
# send_data(data)
# end
# end
#
# EventMachine.run do
# EventMachine.start_server("0.0.0.0", 10000, EchoServer)
# end
#
#
# @example Starting EventMachine event loop in a separate thread
#
# # doesn't block current thread, can be used with Ruby on Rails, Sinatra, Merb, Rack
# # and any other application server that occupies main Ruby thread.
# Thread.new { EventMachine.run }
#
#
# @note This method blocks calling thread. If you need to start EventMachine event loop from a Web app
# running on a non event-driven server (Unicorn, Apache Passenger, Mongrel), do it in a separate thread like demonstrated
# in one of the examples.
# @see file:docs/GettingStarted.md Getting started with EventMachine
# @see EventMachine.stop_event_loop
def self.run blk=nil, tail=nil, &block
# Obsoleted the use_threads mechanism.
# 25Nov06: Added the begin/ensure block. We need to be sure that release_machine
# gets called even if an exception gets thrown within any of the user code
# that the event loop runs. The best way to see this is to run a unit
# test with two functions, each of which calls {EventMachine.run} and each of
# which throws something inside of #run. Without the ensure, the second test
# will start without release_machine being called and will immediately throw
if reactor_running? and @reactor_pid != Process.pid
# Reactor was started in a different parent, meaning we have forked.
# Clean up reactor state so a new reactor boots up in this child.
stop_event_loop
release_machine
@reactor_running = false
end
tail and @tails.unshift(tail)
if reactor_running?
(b = blk || block) and b.call
else
@conns = {}
@acceptors = {}
@timers = {}
@wrapped_exception = nil
@next_tick_queue ||= []
@tails ||= []
begin
@reactor_pid = Process.pid
@reactor_running = true
initialize_event_machine
(b = blk || block) and add_timer(0, b)
if @next_tick_queue && !@next_tick_queue.empty?
add_timer(0) { signal_loopbreak }
end
@reactor_thread = Thread.current
run_machine
ensure
until @tails.empty?
@tails.pop.call
end
begin
release_machine
ensure
if @threadpool
@threadpool.each { |t| t.exit }
@threadpool.each do |t|
next unless t.alive?
begin
# Thread#kill! does not exist on 1.9 or rbx, and raises
# NotImplemented on jruby
t.kill!
rescue NoMethodError, NotImplementedError
t.kill
# XXX t.join here?
end
end
@threadqueue = nil
@resultqueue = nil
@threadpool = nil
end
@next_tick_queue = []
end
@reactor_running = false
@reactor_thread = nil
end
raise @wrapped_exception if @wrapped_exception
end
end
# Sugars a common use case. Will pass the given block to #run, but will terminate
# the reactor loop and exit the function as soon as the code in the block completes.
# (Normally, {EventMachine.run} keeps running indefinitely, even after the block supplied to it
# finishes running, until user code calls {EventMachine.stop})
#
def self.run_block &block
run do
block.call
EventMachine::stop
end
end
# @return [Boolean] true if the calling thread is the same thread as the reactor.
def self.reactor_thread?
Thread.current == @reactor_thread
end
# Runs the given callback on the reactor thread, or immediately if called
# from the reactor thread. Accepts the same arguments as {EventMachine::Callback}
def self.schedule(*a, &b)
cb = Callback(*a, &b)
if reactor_running? && reactor_thread?
cb.call
else
next_tick { cb.call }
end
end
# Forks a new process, properly stops the reactor and then calls {EventMachine.run} inside of it again, passing your block.
def self.fork_reactor &block
# This implementation is subject to change, especially if we clean up the relationship
# of EM#run to @reactor_running.
# Original patch by Aman Gupta.
#
Kernel.fork do
if self.reactor_running?
self.stop_event_loop
self.release_machine
@reactor_running = false
end
self.run block
end
end
# Adds a block to call as the reactor is shutting down.
#
# These callbacks are called in the _reverse_ order to which they are added.
#
# @example Scheduling operations to be run when EventMachine event loop is stopped
#
# EventMachine.run do
# EventMachine.add_shutdown_hook { puts "b" }
# EventMachine.add_shutdown_hook { puts "a" }
# EventMachine.stop
# end
#
# # Outputs:
# # a
# # b
#
def self.add_shutdown_hook &block
@tails << block
end
# Adds a one-shot timer to the event loop.
# Call it with one or two parameters. The first parameters is a delay-time
# expressed in *seconds* (not milliseconds). The second parameter, if
# present, must be an object that responds to :call. If 2nd parameter is not given, then you
# can also simply pass a block to the method call.
#
# This method may be called from the block passed to {EventMachine.run}
# or from any callback method. It schedules execution of the proc or block
# passed to it, after the passage of an interval of time equal to
# *at least* the number of seconds specified in the first parameter to
# the call.
#
# {EventMachine.add_timer} is a non-blocking method. Callbacks can and will
# be called during the interval of time that the timer is in effect.
# There is no built-in limit to the number of timers that can be outstanding at
# any given time.
#
# @example Setting a one-shot timer with EventMachine
#
# EventMachine.run {
# puts "Starting the run now: #{Time.now}"
# EventMachine.add_timer 5, proc { puts "Executing timer event: #{Time.now}" }
# EventMachine.add_timer(10) { puts "Executing timer event: #{Time.now}" }
# }
#
# @param [Integer] delay Delay in seconds
# @see EventMachine::Timer
# @see EventMachine.add_periodic_timer
def self.add_timer *args, &block
interval = args.shift
code = args.shift || block
if code
s = add_oneshot_timer((interval.to_f * 1000).to_i)
@timers[s] = code
s
end
end
# Adds a periodic timer to the event loop.
# It takes the same parameters as the one-shot timer method, {EventMachine.add_timer}.
# This method schedules execution of the given block repeatedly, at intervals
# of time *at least* as great as the number of seconds given in the first
# parameter to the call.
#
# @example Write a dollar-sign to stderr every five seconds, without blocking
#
# EventMachine.run {
# EventMachine.add_periodic_timer( 5 ) { $stderr.write "$" }
# }
#
# @param [Integer] delay Delay in seconds
#
# @see EventMachine::PeriodicTimer
# @see EventMachine.add_timer
#
def self.add_periodic_timer *args, &block
interval = args.shift
code = args.shift || block
EventMachine::PeriodicTimer.new(interval, code)
end
# EventMachine#add_restartable_timer adds a restartable timer to the event loop.
# It takes the same parameters as the one-shot timer method, EventMachine#add_timer.
# This method schedules execution of the given block for a one-shot timer, but can
# be restarted before firing to begin the timer from the start of the interval again.
#
# A restartable timer can be restarted as many times as required, as long as the timer
# has not completed. It can also be cancelled like a regular timer.
#
# === Usage example
#
# The following sample program creates a restartable and then restarts the timer at
# some later time with another shorter timer. The time to complete the restartable
# will be the original interval plus the amount of time passed before being restarted.
#
# EventMachine::run {
# puts "Starting the run now: #{Time.now}"
# timer = EventMachine::add_restartable_timer( 5 ) {
# puts "Executing timer event: #{Time.now}"
# }
# EventMachine::add_timer( 2 ) {
# puts "Restarting timer: #{Time.now}"
# timer.restart
# }
# }
#
#
# Also see EventMachine::RestartableTimer
#
def self.add_restartable_timer *args, &block
interval = args.shift
code = args.shift || block
EventMachine::RestartableTimer.new(interval, code)
end
# Cancel a timer (can be a callback or an {EventMachine::Timer} instance).
#
# @param [#cancel, #call] timer_or_sig A timer to cancel
# @see EventMachine::Timer#cancel
def self.cancel_timer timer_or_sig
if timer_or_sig.respond_to? :cancel
timer_or_sig.cancel
else
@timers[timer_or_sig] = false if @timers.has_key?(timer_or_sig)
end
end
# Causes the processing loop to stop executing, which will cause all open connections and accepting servers
# to be run down and closed. Connection termination callbacks added using {EventMachine.add_shutdown_hook}
# will be called as part of running this method.
#
# When all of this processing is complete, the call to {EventMachine.run} which started the processing loop
# will return and program flow will resume from the statement following {EventMachine.run} call.
#
# @example Stopping a running EventMachine event loop
#
# require 'rubygems'
# require 'eventmachine'
#
# module Redmond
# def post_init
# puts "We're sending a dumb HTTP request to the remote peer."
# send_data "GET / HTTP/1.1\r\nHost: www.microsoft.com\r\n\r\n"
# end
#
# def receive_data data
# puts "We received #{data.length} bytes from the remote peer."
# puts "We're going to stop the event loop now."
# EventMachine::stop_event_loop
# end
#
# def unbind
# puts "A connection has terminated."
# end
# end
#
# puts "We're starting the event loop now."
# EventMachine.run {
# EventMachine.connect "www.microsoft.com", 80, Redmond
# }
# puts "The event loop has stopped."
#
# # This program will produce approximately the following output:
# #
# # We're starting the event loop now.
# # We're sending a dumb HTTP request to the remote peer.
# # We received 1440 bytes from the remote peer.
# # We're going to stop the event loop now.
# # A connection has terminated.
# # The event loop has stopped.
#
#
def self.stop_event_loop
stop
end
# Initiates a TCP server (socket acceptor) on the specified IP address and port.
#
# The IP address must be valid on the machine where the program
# runs, and the process must be privileged enough to listen
# on the specified port (on Unix-like systems, superuser privileges
# are usually required to listen on any port lower than 1024).
# Only one listener may be running on any given address/port
# combination. start_server will fail if the given address and port
# are already listening on the machine, either because of a prior call
# to {.start_server} or some unrelated process running on the machine.
# If {.start_server} succeeds, the new network listener becomes active
# immediately and starts accepting connections from remote peers,
# and these connections generate callback events that are processed
# by the code specified in the handler parameter to {.start_server}.
#
# The optional handler which is passed to this method is the key
# to EventMachine's ability to handle particular network protocols.
# The handler parameter passed to start_server must be a Ruby Module
# that you must define. When the network server that is started by
# start_server accepts a new connection, it instantiates a new
# object of an anonymous class that is inherited from {EventMachine::Connection},
# *into which your handler module have been included*.
#
# Your handler module may override any of the methods in {EventMachine::Connection},
# such as {EventMachine::Connection#receive_data}, in order to implement the specific behavior
# of the network protocol.
#
# Callbacks invoked in response to network events *always* take place
# within the execution context of the object derived from {EventMachine::Connection}
# extended by your handler module. There is one object per connection, and
# all of the callbacks invoked for a particular connection take the form
# of instance methods called against the corresponding {EventMachine::Connection}
# object. Therefore, you are free to define whatever instance variables you
# wish, in order to contain the per-connection state required by the network protocol you are
# implementing.
#
# {EventMachine.start_server} is usually called inside the block passed to {EventMachine.run},
# but it can be called from any EventMachine callback. {EventMachine.start_server} will fail
# unless the EventMachine event loop is currently running (which is why
# it's often called in the block suppled to {EventMachine.run}).
#
# You may call start_server any number of times to start up network
# listeners on different address/port combinations. The servers will
# all run simultaneously. More interestingly, each individual call to start_server
# can specify a different handler module and thus implement a different
# network protocol from all the others.
#
# @example
#
# require 'rubygems'
# require 'eventmachine'
#
# # Here is an example of a server that counts lines of input from the remote
# # peer and sends back the total number of lines received, after each line.
# # Try the example with more than one client connection opened via telnet,
# # and you will see that the line count increments independently on each
# # of the client connections. Also very important to note, is that the
# # handler for the receive_data function, which our handler redefines, may
# # not assume that the data it receives observes any kind of message boundaries.
# # Also, to use this example, be sure to change the server and port parameters
# # to the start_server call to values appropriate for your environment.
# module LineCounter
# MaxLinesPerConnection = 10
#
# def post_init
# puts "Received a new connection"
# @data_received = ""
# @line_count = 0
# end
#
# def receive_data data
# @data_received << data
# while @data_received.slice!( /^[^\n]*[\n]/m )
# @line_count += 1
# send_data "received #{@line_count} lines so far\r\n"
# @line_count == MaxLinesPerConnection and close_connection_after_writing
# end
# end
# end
#
# EventMachine.run {
# host, port = "192.168.0.100", 8090
# EventMachine.start_server host, port, LineCounter
# puts "Now accepting connections on address #{host}, port #{port}..."
# EventMachine.add_periodic_timer(10) { $stderr.write "*" }
# }
#
# @param [String] server Host to bind to.
# @param [Integer] port Port to bind to.
# @param [Module, Class] handler A module or class that implements connection callbacks
#
# @note Don't forget that in order to bind to ports < 1024 on Linux, *BSD and Mac OS X your process must have superuser privileges.
#
# @see file:docs/GettingStarted.md EventMachine tutorial
# @see EventMachine.stop_server
def self.start_server server, port=nil, handler=nil, *args, &block
begin
port = Integer(port)
rescue ArgumentError, TypeError
# there was no port, so server must be a unix domain socket
# the port argument is actually the handler, and the handler is one of the args
args.unshift handler if handler
handler = port
port = nil
end if port
klass = klass_from_handler(Connection, handler, *args)
s = if port
start_tcp_server server, port
else
start_unix_server server
end
@acceptors[s] = [klass,args,block]
s
end
# Stop a TCP server socket that was started with {EventMachine.start_server}.
# @see EventMachine.start_server
def self.stop_server signature
stop_tcp_server signature
end
# Start a Unix-domain server.
#
# Note that this is an alias for {EventMachine.start_server}, which can be used to start both
# TCP and Unix-domain servers.
#
# @see EventMachine.start_server
def self.start_unix_domain_server filename, *args, &block
start_server filename, *args, &block
end
# Initiates a TCP connection to a remote server and sets up event handling for the connection.
# {EventMachine.connect} requires event loop to be running (see {EventMachine.run}).
#
# {EventMachine.connect} takes the IP address (or hostname) and
# port of the remote server you want to connect to.
# It also takes an optional handler (a module or a subclass of {EventMachine::Connection}) which you must define, that
# contains the callbacks that will be invoked by the event loop on behalf of the connection.
#
# Learn more about connection lifecycle callbacks in the {file:docs/GettingStarted.md EventMachine tutorial} and
# {file:docs/ConnectionLifecycleCallbacks.md Connection lifecycle guide}.
#
#
# @example
#
# # Here's a program which connects to a web server, sends a naive
# # request, parses the HTTP header of the response, and then
# # (antisocially) ends the event loop, which automatically drops the connection
# # (and incidentally calls the connection's unbind method).
# module DumbHttpClient
# def post_init
# send_data "GET / HTTP/1.1\r\nHost: _\r\n\r\n"
# @data = ""
# @parsed = false
# end
#
# def receive_data data
# @data << data
# if !@parsed and @data =~ /[\n][\r]*[\n]/m
# @parsed = true
# puts "RECEIVED HTTP HEADER:"
# $`.each {|line| puts ">>> #{line}" }
#
# puts "Now we'll terminate the loop, which will also close the connection"
# EventMachine::stop_event_loop
# end
# end
#
# def unbind
# puts "A connection has terminated"
# end
# end
#
# EventMachine.run {
# EventMachine.connect "www.bayshorenetworks.com", 80, DumbHttpClient
# }
# puts "The event loop has ended"
#
#
# @example Defining protocol handler as a class
#
# class MyProtocolHandler < EventMachine::Connection
# def initialize *args
# super
# # whatever else you want to do here
# end
#
# # ...
# end
#
#
# @param [String] server Host to connect to
# @param [Integer] port Port to connect to
# @param [Module, Class] handler A module or class that implements connection lifecycle callbacks
#
# @see EventMachine.start_server
# @see file:docs/GettingStarted.md EventMachine tutorial
def self.connect server, port=nil, handler=nil, *args, &blk
# EventMachine::connect initiates a TCP connection to a remote
# server and sets up event-handling for the connection.
# It internally creates an object that should not be handled
# by the caller. HOWEVER, it's often convenient to get the
# object to set up interfacing to other objects in the system.
# We return the newly-created anonymous-class object to the caller.
# It's expected that a considerable amount of code will depend
# on this behavior, so don't change it.
#
# Ok, added support for a user-defined block, 13Apr06.
# This leads us to an interesting choice because of the
# presence of the post_init call, which happens in the
# initialize method of the new object. We call the user's
# block and pass the new object to it. This is a great
# way to do protocol-specific initiation. It happens
# AFTER post_init has been called on the object, which I
# certainly hope is the right choice.
# Don't change this lightly, because accepted connections
# are different from connected ones and we don't want
# to have them behave differently with respect to post_init
# if at all possible.
bind_connect nil, nil, server, port, handler, *args, &blk
end
# This method is like {EventMachine.connect}, but allows for a local address/port
# to bind the connection to.
#
# @see EventMachine.connect
def self.bind_connect bind_addr, bind_port, server, port=nil, handler=nil, *args
begin
port = Integer(port)
rescue ArgumentError, TypeError
# there was no port, so server must be a unix domain socket
# the port argument is actually the handler, and the handler is one of the args
args.unshift handler if handler
handler = port
port = nil
end if port
klass = klass_from_handler(Connection, handler, *args)
s = if port
if bind_addr
bind_connect_server bind_addr, bind_port.to_i, server, port
else
connect_server server, port
end
else
connect_unix_server server
end
c = klass.new s, *args
@conns[s] = c
block_given? and yield c
c
end
# {EventMachine.watch} registers a given file descriptor or IO object with the eventloop. The
# file descriptor will not be modified (it will remain blocking or non-blocking).
#
# The eventloop can be used to process readable and writable events on the file descriptor, using
# {EventMachine::Connection#notify_readable=} and {EventMachine::Connection#notify_writable=}
#
# {EventMachine::Connection#notify_readable?} and {EventMachine::Connection#notify_writable?} can be used
# to check what events are enabled on the connection.
#
# To detach the file descriptor, use {EventMachine::Connection#detach}
#
# @example
#
# module SimpleHttpClient
# def notify_readable
# header = @io.readline
#
# if header == "\r\n"
# # detach returns the file descriptor number (fd == @io.fileno)
# fd = detach
# end
# rescue EOFError
# detach
# end
#
# def unbind
# EM.next_tick do
# # socket is detached from the eventloop, but still open
# data = @io.read
# end
# end
# end
#
# EventMachine.run {
# sock = TCPSocket.new('site.com', 80)
# sock.write("GET / HTTP/1.0\r\n\r\n")
# conn = EventMachine.watch(sock, SimpleHttpClient)
# conn.notify_readable = true
# }
#
# @author Riham Aldakkak (eSpace Technologies)
def self.watch io, handler=nil, *args, &blk
attach_io io, true, handler, *args, &blk
end
# Attaches an IO object or file descriptor to the eventloop as a regular connection.
# The file descriptor will be set as non-blocking, and EventMachine will process
# receive_data and send_data events on it as it would for any other connection.
#
# To watch a fd instead, use {EventMachine.watch}, which will not alter the state of the socket
# and fire notify_readable and notify_writable events instead.
def self.attach io, handler=nil, *args, &blk
attach_io io, false, handler, *args, &blk
end
# @private
def self.attach_io io, watch_mode, handler=nil, *args
klass = klass_from_handler(Connection, handler, *args)
if !watch_mode and klass.public_instance_methods.any?{|m| [:notify_readable, :notify_writable].include? m.to_sym }
raise ArgumentError, "notify_readable/writable with EM.attach is not supported. Use EM.watch(io){ |c| c.notify_readable = true }"
end
if io.respond_to?(:fileno)
fd = defined?(JRuby) ? JRuby.runtime.getDescriptorByFileno(io.fileno).getChannel : io.fileno
else
fd = io
end
s = attach_fd fd, watch_mode
c = klass.new s, *args
c.instance_variable_set(:@io, io)
c.instance_variable_set(:@watch_mode, watch_mode)
c.instance_variable_set(:@fd, fd)
@conns[s] = c
block_given? and yield c
c
end
# Attaches a server IO object or file descriptor to the eventloop.
# This function behaves just like start_server but allows you to reuse
# an already existing file descriptor instead of having EventMachine create
# one. The descriptor must be accept()able and will be set as non-blocking.
#
# Unlike start_server however, the file descriptor is not closed when
# EventMachine is released, so you will have to do any cleanups manually.
# If +io+ is an IO object then a reference to it will be kept until
# EventMachine is released, so that the file descriptor isn't accidentally
# closed by the garbage collector.
def self.attach_server io, handler = nil, *args, &block
klass = klass_from_handler(Connection, handler, *args)
if io.respond_to?(:fileno)
fd = defined?(JRuby) ? JRuby.runtime.getDescriptorByFileno(io.fileno).getChannel : io.fileno
else
fd = io
end
s = attach_server_fd(fd)
@acceptors[s] = [klass,args,block,io]
s
end
# Connect to a given host/port and re-use the provided {EventMachine::Connection} instance.
# Consider also {EventMachine::Connection#reconnect}.
#
# @see EventMachine::Connection#reconnect
def self.reconnect server, port, handler
# Observe, the test for already-connected FAILS if we call a reconnect inside post_init,
# because we haven't set up the connection in @conns by that point.
# RESIST THE TEMPTATION to "fix" this problem by redefining the behavior of post_init.
#
# Changed 22Nov06: if called on an already-connected handler, just return the
# handler and do nothing more. Originally this condition raised an exception.
# We may want to change it yet again and call the block, if any.
raise "invalid handler" unless handler.respond_to?(:connection_completed)
#raise "still connected" if @conns.has_key?(handler.signature)
return handler if @conns.has_key?(handler.signature)
s = if port
connect_server server, port
else
connect_unix_server server
end
handler.signature = s
@conns[s] = handler
block_given? and yield handler
handler
end
# Make a connection to a Unix-domain socket. This method is simply an alias for {.connect},
# which can connect to both TCP and Unix-domain sockets. Make sure that your process has sufficient
# permissions to open the socket it is given.
#
# @param [String] socketname Unix domain socket (local fully-qualified path) you want to connect to.
#
# @note UNIX sockets, as the name suggests, are not available on Microsoft Windows.
def self.connect_unix_domain socketname, *args, &blk
connect socketname, *args, &blk
end
# Used for UDP-based protocols. Its usage is similar to that of {EventMachine.start_server}.
#
# This method will create a new UDP (datagram) socket and
# bind it to the address and port that you specify.
# The normal callbacks (see {EventMachine.start_server}) will
# be called as events of interest occur on the newly-created
# socket, but there are some differences in how they behave.
#
# {Connection#receive_data} will be called when a datagram packet
# is received on the socket, but unlike TCP sockets, the message
# boundaries of the received data will be respected. In other words,
# if the remote peer sent you a datagram of a particular size,
# you may rely on {Connection#receive_data} to give you the
# exact data in the packet, with the original data length.
# Also observe that Connection#receive_data may be called with a
# *zero-length* data payload, since empty datagrams are permitted in UDP.
#
# {Connection#send_data} is available with UDP packets as with TCP,
# but there is an important difference. Because UDP communications
# are *connectionless*, there is no implicit recipient for the packets you
# send. Ordinarily you must specify the recipient for each packet you send.
# However, EventMachine provides for the typical pattern of receiving a UDP datagram
# from a remote peer, performing some operation, and then sending
# one or more packets in response to the same remote peer.
# To support this model easily, just use {Connection#send_data}
# in the code that you supply for {Connection#receive_data}.
#
# EventMachine will provide an implicit return address for any messages sent to
# {Connection#send_data} within the context of a {Connection#receive_data} callback,
# and your response will automatically go to the correct remote peer.
#
# Observe that the port number that you supply to {EventMachine.open_datagram_socket}
# may be zero. In this case, EventMachine will create a UDP socket
# that is bound to an [ephemeral port](http://en.wikipedia.org/wiki/Ephemeral_port).
# This is not appropriate for servers that must publish a well-known
# port to which remote peers may send datagrams. But it can be useful
# for clients that send datagrams to other servers.
# If you do this, you will receive any responses from the remote
# servers through the normal {Connection#receive_data} callback.
# Observe that you will probably have issues with firewalls blocking
# the ephemeral port numbers, so this technique is most appropriate for LANs.
#
# If you wish to send datagrams to arbitrary remote peers (not
# necessarily ones that have sent data to which you are responding),
# then see {Connection#send_datagram}.
#
# DO NOT call send_data from a datagram socket outside of a {Connection#receive_data} method. Use {Connection#send_datagram}.
# If you do use {Connection#send_data} outside of a {Connection#receive_data} method, you'll get a confusing error
# because there is no "peer," as #send_data requires (inside of {EventMachine::Connection#receive_data},
# {EventMachine::Connection#send_data} "fakes" the peer as described above).
#
# @param [String] address IP address
# @param [String] port Port
# @param [Class, Module] handler A class or a module that implements connection lifecycle callbacks.
def self.open_datagram_socket address, port, handler=nil, *args
# Replaced the implementation on 01Oct06. Thanks to Tobias Gustafsson for pointing
# out that this originally did not take a class but only a module.
klass = klass_from_handler(Connection, handler, *args)
s = open_udp_socket address, port.to_i
c = klass.new s, *args
@conns[s] = c
block_given? and yield c
c
end
# For advanced users. This function sets the default timer granularity, which by default is
# slightly smaller than 100 milliseconds. Call this function to set a higher or lower granularity.
# The function affects the behavior of {EventMachine.add_timer} and {EventMachine.add_periodic_timer}.
# Most applications will not need to call this function.
#
# Avoid setting the quantum to very low values because that may reduce performance under some extreme conditions.
# We recommend that you not use values lower than 10.
#
# This method only can be used if event loop is running.
#
# @param [Integer] mills New timer granularity, in milliseconds
#
# @see EventMachine.add_timer
# @see EventMachine.add_periodic_timer
# @see EventMachine::Timer
# @see EventMachine.run
def self.set_quantum mills
set_timer_quantum mills.to_i
end
# Max number of timers is removed in EventMachine-LE, so this method does nothing.
def self.set_max_timers ct
true
end
# Max number of timers is removed in EventMachine-LE, so this method does nothing.
def self.get_max_timers
# Return "a lot", since there is no limit now.
2**28
end
# Returns the total number of connections (file descriptors) currently held by the reactor.
# Note that a tick must pass after the 'initiation' of a connection for this number to increment.
# It's usually accurate, but don't rely on the exact precision of this number unless you really know EM internals.
#
# @example
#
# EventMachine.run {
# EventMachine.connect("rubyeventmachine.com", 80)
# # count will be 0 in this case, because connection is not
# # established yet
# count = EventMachine.connection_count
# }
#
#
# @example
#
# EventMachine.run {
# EventMachine.connect("rubyeventmachine.com", 80)
#
# EventMachine.next_tick {
# # In this example, count will be 1 since the connection has been established in
# # the next loop of the reactor.
# count = EventMachine.connection_count
# }
# }
#
# @return [Integer] Number of connections currently held by the reactor.
def self.connection_count
get_connection_count
end
# The is the responder for the loopback-signalled event.
# It can be fired either by code running on a separate thread ({EventMachine.defer}) or on
# the main thread ({EventMachine.next_tick}).
# It will often happen that a next_tick handler will reschedule itself. We
# consume a copy of the tick queue so that tick events scheduled by tick events
# have to wait for the next pass through the reactor core.
#
# @private
def self.run_deferred_callbacks
until (@resultqueue ||= []).empty?
result,cback = @resultqueue.pop
cback.call result if cback
end
# Capture the size at the start of this tick...
size = @next_tick_mutex.synchronize { @next_tick_queue.size }
size.times do |i|
callback = @next_tick_mutex.synchronize { @next_tick_queue.shift }
begin
callback.call
ensure
# This is a little nasty. The problem is, if an exception occurs during
# the callback, then we need to send a signal to the reactor to actually
# do some work during the next_tick. The only mechanism we have from the
# ruby side is next_tick itself, although ideally, we'd just drop a byte
# on the loopback descriptor.
EM.next_tick {} if $!
end
end
end
# EventMachine.defer is used for integrating blocking operations into EventMachine's control flow.
# The action of {.defer} is to take the block specified in the first parameter (the "operation")
# and schedule it for asynchronous execution on an internal thread pool maintained by EventMachine.
# When the operation completes, it will pass the result computed by the block (if any)
# back to the EventMachine reactor. Then, EventMachine calls the block specified in the
# second parameter to {.defer} (the "callback"), as part of its normal event handling loop.
# The result computed by the operation block is passed as a parameter to the callback.
# You may omit the callback parameter if you don't need to execute any code after the operation completes.
#
# ## Caveats ##
#
# Note carefully that the code in your deferred operation will be executed on a separate
# thread from the main EventMachine processing and all other Ruby threads that may exist in
# your program. Also, multiple deferred operations may be running at once! Therefore, you
# are responsible for ensuring that your operation code is threadsafe.
#
# Don't write a deferred operation that will block forever. If so, the current implementation will
# not detect the problem, and the thread will never be returned to the pool. EventMachine limits
# the number of threads in its pool, so if you do this enough times, your subsequent deferred
# operations won't get a chance to run.
#
# @example
#
# operation = proc {
# # perform a long-running operation here, such as a database query.
# "result" # as usual, the last expression evaluated in the block will be the return value.
# }
# callback = proc {|result|
# # do something with result here, such as send it back to a network client.
# }
#
# EventMachine.defer(operation, callback)
#
# @param [#call] op An operation you want to offload to EventMachine thread pool
# @param [#call] callback A callback that will be run on the event loop thread after `operation` finishes.
#
# @see EventMachine.threadpool_size
def self.defer op = nil, callback = nil, &blk
# OBSERVE that #next_tick hacks into this mechanism, so don't make any changes here
# without syncing there.
#
# Running with $VERBOSE set to true gives a warning unless all ivars are defined when
# they appear in rvalues. But we DON'T ever want to initialize @threadqueue unless we
# need it, because the Ruby threads are so heavyweight. We end up with this bizarre
# way of initializing @threadqueue because EventMachine is a Module, not a Class, and
# has no constructor.
unless @threadpool
require 'thread'
@threadpool = []
@threadqueue = ::Queue.new
@resultqueue = ::Queue.new
spawn_threadpool
end
@threadqueue << [op||blk,callback]
end
# @private
def self.spawn_threadpool
until @threadpool.size == @threadpool_size.to_i
@threadpool << Thread.new do
Thread.current.abort_on_exception = true
while true
op, cback = *@threadqueue.pop
result = op.call
@resultqueue << [result, cback]
EventMachine.signal_loopbreak
end
end
end
end
class << self
# @private
attr_reader :threadpool
# Size of the EventMachine.defer threadpool (defaults to 20)
# @return [Number]
attr_accessor :threadpool_size
EventMachine.threadpool_size = 20
end
# Schedules a proc for execution immediately after the next "turn" through the reactor
# core. An advanced technique, this can be useful for improving memory management and/or
# application responsiveness, especially when scheduling large amounts of data for
# writing to a network connection.
#
# This method takes either a single argument (which must be a callable object) or a block.
#
# @param [#call] pr A callable object to run
def self.next_tick pr=nil, &block
# This works by adding to the @resultqueue that's used for #defer.
# The general idea is that next_tick is used when we want to give the reactor a chance
# to let other operations run, either to balance the load out more evenly, or to let
# outbound network buffers drain, or both. So we probably do NOT want to block, and
# we probably do NOT want to be spinning any threads. A program that uses next_tick
# but not #defer shouldn't suffer the penalty of having Ruby threads running. They're
# extremely expensive even if they're just sleeping.
raise ArgumentError, "no proc or block given" unless ((pr && pr.respond_to?(:call)) or block)
@next_tick_mutex.synchronize do
@next_tick_queue << ( pr || block )
end
signal_loopbreak if reactor_running?
end
# A wrapper over the setuid system call. Particularly useful when opening a network
# server on a privileged port because you can use this call to drop privileges
# after opening the port. Also very useful after a call to {.set_descriptor_table_size},
# which generally requires that you start your process with root privileges.
#
# This method is intended for use in enforcing security requirements, consequently
# it will throw a fatal error and end your program if it fails.
#
# @param [String] username The effective name of the user whose privilege-level your process should attain.
#
# @note This method has no effective implementation on Windows or in the pure-Ruby
# implementation of EventMachine
def self.set_effective_user username
setuid_string username
end
# Sets the maximum number of file or socket descriptors that your process may open.
# If you call this method with no arguments, it will simply return
# the current size of the descriptor table without attempting to change it.
#
# The new limit on open descriptors **only** applies to sockets and other descriptors
# that belong to EventMachine. It has **no effect** on the number of descriptors
# you can create in ordinary Ruby code.
#
# Not available on all platforms. Increasing the number of descriptors beyond its
# default limit usually requires superuser privileges. (See {.set_effective_user}
# for a way to drop superuser privileges while your program is running.)
#
# @param [Integer] n_descriptors The maximum number of file or socket descriptors that your process may open
# @return [Integer] The new descriptor table size.
def self.set_descriptor_table_size n_descriptors=nil
set_rlimit_nofile n_descriptors
end
# Runs an external process.
#
# @example
#
# module RubyCounter
# def post_init
# # count up to 5
# send_data "5\n"
# end
# def receive_data data
# puts "ruby sent me: #{data}"
# end
# def unbind
# puts "ruby died with exit status: #{get_status.exitstatus}"
# end
# end
#
# EventMachine.run {
# EventMachine.popen("ruby -e' $stdout.sync = true; gets.to_i.times{ |i| puts i+1; sleep 1 } '", RubyCounter)
# }
#
# @note This method is not supported on Microsoft Windows
# @see EventMachine::DeferrableChildProcess
# @see EventMachine.system
def self.popen cmd, handler=nil, *args
# At this moment, it's only available on Unix.
# Perhaps misnamed since the underlying function uses socketpair and is full-duplex.
klass = klass_from_handler(Connection, handler, *args)
w = Shellwords::shellwords( cmd )
w.unshift( w.first ) if w.first
s = invoke_popen( w )
c = klass.new s, *args
@conns[s] = c
yield(c) if block_given?
c
end
# Tells you whether the EventMachine reactor loop is currently running.
#
# Useful when writing libraries that want to run event-driven code, but may
# be running in programs that are already event-driven. In such cases, if {EventMachine.reactor_running?}
# returns false, your code can invoke {EventMachine.run} and run your application code inside
# the block passed to that method. If this method returns true, just
# execute your event-aware code.
#
# @return [Boolean] true if the EventMachine reactor loop is currently running
def self.reactor_running?
!!@reactor_running
end
# (Experimental)
#
# @private
def self.open_keyboard handler=nil, *args
klass = klass_from_handler(Connection, handler, *args)
s = read_keyboard
c = klass.new s, *args
@conns[s] = c
block_given? and yield c
c
end
# EventMachine's file monitoring API. Currently supported are the following events
# on individual files, using inotify on Linux systems, and kqueue for *BSD and Mac OS X:
#
# * File modified (written to)
# * File moved/renamed
# * File deleted
#
# EventMachine::watch_file takes a filename and a handler Module containing your custom callback methods.
# This will setup the low level monitoring on the specified file, and create a new EventMachine::FileWatch
# object with your Module mixed in. FileWatch is a subclass of {EventMachine::Connection}, so callbacks on this object
# work in the familiar way. The callbacks that will be fired by EventMachine are:
#
# * file_modified
# * file_moved
# * file_deleted
#
# You can access the filename being monitored from within this object using {FileWatch#path}.
#
# When a file is deleted, {FileWatch#stop_watching} will be called after your file_deleted callback,
# to clean up the underlying monitoring and remove EventMachine's reference to the now-useless {FileWatch} instance.
# This will in turn call unbind, if you wish to use it.
#
# The corresponding system-level Errno will be raised when attempting to monitor non-existent files,
# files with wrong permissions, or if an error occurs dealing with inotify/kqueue.
#
# @example
#
# # Before running this example, make sure we have a file to monitor:
# # $ echo "bar" > /tmp/foo
#
# module Handler
# def file_modified
# puts "#{path} modified"
# end
#
# def file_moved
# puts "#{path} moved"
# end
#
# def file_deleted
# puts "#{path} deleted"
# end
#
# def unbind
# puts "#{path} monitoring ceased"
# end
# end
#
# # for efficient file watching, use kqueue on Mac OS X
# EventMachine.kqueue = true if EventMachine.kqueue?
#
# EventMachine.run {
# EventMachine.watch_file("/tmp/foo", Handler)
# }
#
# # $ echo "baz" >> /tmp/foo => "/tmp/foo modified"
# # $ mv /tmp/foo /tmp/oof => "/tmp/foo moved"
# # $ rm /tmp/oof => "/tmp/foo deleted"
#
# @note The ability to pick up on the new filename after a rename is not yet supported.
# Calling #path will always return the filename you originally used.
#
# @param [String] filename Local path to the file to watch.
# @param [Class, Module] handler A class or module that implements event handlers associated with the file.
def self.watch_file(filename, handler=nil, *args)
klass = klass_from_handler(FileWatch, handler, *args)
s = watch_filename(filename)
c = klass.new s, *args
# we have to set the path like this because of how Connection.new works
c.instance_variable_set("@path", filename)
@conns[s] = c
block_given? and yield c
c
end
# EventMachine's process monitoring API. On Mac OS X and *BSD this method is implemented using kqueue.
#
# @example
#
# module ProcessWatcher
# def process_exited
# put 'the forked child died!'
# end
# end
#
# pid = fork{ sleep }
#
# EventMachine.run {
# EventMachine.watch_process(pid, ProcessWatcher)
# EventMachine.add_timer(1){ Process.kill('TERM', pid) }
# }
#
# @param [Integer] pid PID of the process to watch.
# @param [Class, Module] handler A class or module that implements event handlers associated with the file.
def self.watch_process(pid, handler=nil, *args)
pid = pid.to_i
klass = klass_from_handler(ProcessWatch, handler, *args)
s = watch_pid(pid)
c = klass.new s, *args
# we have to set the path like this because of how Connection.new works
c.instance_variable_set("@pid", pid)
@conns[s] = c
block_given? and yield c
c
end
# Catch-all for errors raised during event loop callbacks.
#
# @example
#
# EventMachine.error_handler{ |e|
# puts "Error raised during event loop: #{e.message}"
# }
#
# @param [#call] cb Global catch-all errback
def self.error_handler cb = nil, &blk
if cb or blk
@error_handler = cb || blk
elsif instance_variable_defined? :@error_handler
remove_instance_variable :@error_handler
end
end
# This method allows for direct writing of incoming data back out to another descriptor, at the C++ level in the reactor.
# This is very efficient and especially useful for proxies where high performance is required. Propogating data from a server response
# all the way up to Ruby, and then back down to the reactor to be sent back to the client, is often unnecessary and
# incurs a significant performance decrease.
#
# The two arguments are instance of {EventMachine::Connection} subclasses, 'from' and 'to'. 'from' is the connection whose inbound data you want
# relayed back out. 'to' is the connection to write it to.
#
# Once you call this method, the 'from' connection will no longer get receive_data callbacks from the reactor,
# except in the case that 'to' connection has already closed when attempting to write to it. You can see
# in the example, that proxy_target_unbound will be called when this occurs. After that, further incoming
# data will be passed into receive_data as normal.
#
# Note also that this feature supports different types of descriptors: TCP, UDP, and pipes. You can relay
# data from one kind to another, for example, feed a pipe from a UDP stream.
#
# @example
#
# module ProxyConnection
# def initialize(client, request)
# @client, @request = client, request
# end
#
# def post_init
# EM::enable_proxy(self, @client)
# end
#
# def connection_completed
# send_data @request
# end
#
# def proxy_target_unbound
# close_connection
# end
#
# def unbind
# @client.close_connection_after_writing
# end
# end
#
# module ProxyServer
# def receive_data(data)
# (@buf ||= "") << data
# if @buf =~ /\r\n\r\n/ # all http headers received
# EventMachine.connect("10.0.0.15", 80, ProxyConnection, self, data)
# end
# end
# end
#
# EventMachine.run {
# EventMachine.start_server("127.0.0.1", 8080, ProxyServer)
# }
#
# @param [EventMachine::Connection] from Source of data to be proxies/streamed.
# @param [EventMachine::Connection] to Destination of data to be proxies/streamed.
# @param [Integer] bufsize Buffer size to use
# @param [Integer] length Maximum number of bytes to proxy.
#
# @see EventMachine.disable_proxy
def self.enable_proxy(from, to, bufsize=0, length=0)
start_proxy(from.signature, to.signature, bufsize, length)
end
# Takes just one argument, a {Connection} that has proxying enabled via {EventMachine.enable_proxy}.
# Calling this method will remove that functionality and your connection will begin receiving
# data via {Connection#receive_data} again.
#
# @param [EventMachine::Connection] from Source of data that is being proxied
# @see EventMachine.enable_proxy
def self.disable_proxy(from)
stop_proxy(from.signature)
end
# Retrieve the heartbeat interval. This is how often EventMachine will check for dead connections
# that have had an inactivity timeout set via {Connection#set_comm_inactivity_timeout}.
# Default is 2 seconds.
#
# @return [Integer] Heartbeat interval, in seconds
def self.heartbeat_interval
get_heartbeat_interval
end
# Set the heartbeat interval. This is how often EventMachine will check for dead connections
# that have had an inactivity timeout set via {Connection#set_comm_inactivity_timeout}.
# Takes a Numeric number of seconds. Default is 2.
#
# @param [Integer] time Heartbeat interval, in seconds
def self.heartbeat_interval=(time)
set_heartbeat_interval time.to_f
end
# @private
def self.event_callback conn_binding, opcode, data
#
# Changed 27Dec07: Eliminated the hookable error handling.
# No one was using it, and it degraded performance significantly.
# It's in original_event_callback, which is dead code.
#
# Changed 25Jul08: Added a partial solution to the problem of exceptions
# raised in user-written event-handlers. If such exceptions are not caught,
# we must cause the reactor to stop, and then re-raise the exception.
# Otherwise, the reactor doesn't stop and it's left on the call stack.
# This is partial because we only added it to #unbind, where it's critical
# (to keep unbind handlers from being re-entered when a stopping reactor
# runs down open connections). It should go on the other calls to user
# code, but the performance impact may be too large.
#
if opcode == ConnectionUnbound
if c = @conns.delete( conn_binding )
begin
if c.original_method(:unbind).arity != 0
c.unbind(data == 0 ? nil : EventMachine::ERRNOS[data])
else
c.unbind
end
# If this is an attached (but not watched) connection, close the underlying io object.
if c.instance_variable_defined?(:@io) and !c.instance_variable_get(:@watch_mode)
io = c.instance_variable_get(:@io)
begin
io.close
rescue Errno::EBADF, IOError
end
end
rescue
@wrapped_exception = $!
stop
end
elsif c = @acceptors.delete( conn_binding )
# no-op
else
if $! # Bubble user generated errors.
@wrapped_exception = $!
EM.stop
else
raise ConnectionNotBound, "received ConnectionUnbound for an unknown signature: #{conn_binding}"
end
end
elsif opcode == ConnectionAccepted
accep,args,blk = @acceptors[conn_binding]
raise NoHandlerForAcceptedConnection unless accep
c = accep.new data, *args
@conns[data] = c
blk and blk.call(c)
c # (needed?)
##
# The remaining code is a fallback for the pure ruby and java reactors.
# In the C++ reactor, these events are handled in the C event_callback() in rubymain.cpp
elsif opcode == ConnectionCompleted
c = @conns[conn_binding] or raise ConnectionNotBound, "received ConnectionCompleted for unknown signature: #{conn_binding}"
c.connection_completed
elsif opcode == TimerFired
t = @timers.delete( data )
return if t == false # timer cancelled
t or raise UnknownTimerFired, "timer data: #{data}"
t.call
elsif opcode == ConnectionData
c = @conns[conn_binding] or raise ConnectionNotBound, "received data #{data} for unknown signature: #{conn_binding}"
c.receive_data data
elsif opcode == LoopbreakSignalled
run_deferred_callbacks
elsif opcode == ConnectionNotifyReadable
c = @conns[conn_binding] or raise ConnectionNotBound
c.notify_readable
elsif opcode == ConnectionNotifyWritable
c = @conns[conn_binding] or raise ConnectionNotBound
c.notify_writable
end
end
#
#
# @private
def self._open_file_for_writing filename, handler=nil
klass = klass_from_handler(Connection, handler)
s = _write_file filename
c = klass.new s
@conns[s] = c
block_given? and yield c
c
end
# @private
def self.klass_from_handler(klass = Connection, handler = nil, *args)
klass = if handler.is_a?(Class)
raise ArgumentError, "must provide module or subclass of #{klass.name}" unless klass >= handler
handler
elsif handler
if handler.const_defined?(:EM_CONNECTION_CLASS)
handler::EM_CONNECTION_CLASS
else
handler::const_set(:EM_CONNECTION_CLASS, Class.new(klass) {include handler})
end
else
klass
end
arity = klass.instance_method(:initialize).arity
expected = arity >= 0 ? arity : -(arity + 1)
if (arity >= 0 and args.size != expected) or (arity < 0 and args.size < expected)
raise ArgumentError, "wrong number of arguments for #{klass}#initialize (#{args.size} for #{expected})"
end
klass
end
end # module EventMachine
# Alias for {EventMachine}
EM = EventMachine
# Alias for {EventMachine::Protocols}
EM::P = EventMachine::Protocols
Jump to Line
Something went wrong with that request. Please try again.