EventMachine-LE

EventMachine-LE (Live Edition) is a branch of EventMachine with fixes and more features.

What do you mean by "branch"?

Well, outside the narrower git circles, "fork" has all these negative connotations, as in bad feelings after an argument, marriages divorcing, nation states splitting after a civil war, people hating each other. This is not at all the point here, so let's call this fork a "branch".

Purpose of this branch

This branch incorporates interesting pull requests that are not yet included in the mainline EventMachine repository. The maintainers of that version prefer to minimize change in order to keep the stability with already existing EventMachine deployments, which provides an impressive multi-platform base for IPv4 TCP servers (e.g., Web servers) that don't need good UDP or IPv6 support.

This dedication to stability is helpful for production use, but can also lead to ossification. The present "Live Edition" or "Leading Edge" branch has its focus on supporting a somewhat wider use, including new Web servers or protocols beyond the HTTP Web.

To provide even more focus, this branch is currently applying its energy towards Linux and Unix/BSD/OSX environments. Java reactor and pure Ruby reactor are for now removed in this branch, and Windows/Cygwin support is untested. This may very well change later, once interesting pull requests come in.

EventMachine-LE draws from a number of dormant pull requests on the mainline version of EventMachine. New proposals will also directly come to EventMachine-LE and will be included once they are tested.

This is not a "development branch" — we do use EventMachine-LE in production, just beyond the focus of mainline EventMachine.

The intention is that EventMachine-LE is always a drop-in replacement for EventMachine, just with additional (and fixed) functionality.

Features and changes

The list of additions and improvements will grow over time. Currently the following features/fixes have been applied in EventMachine-LE:

Version 1.1.6

• Avoid CPU at 100% when calling close_connection after a connection has been unbind: ept.

Version 1.1.5

• Fix bug when the system time is changed to earlier time (which made EM to eat up the CPU cycle): commit in EM.
• Fix crash on attach/detach in the same tick (pietern).
• Fix EM.system when unicode characters used (funny-falcon).
• Fix SMTP server behaviour to reset mail transaction state after sending message (jonasschneider).

Version 1.1.4 and below

• Full IPv6 support for TCP and UDP, in both server and client mode (cabo).
• Added robustness to datagram sockets, which now can optionally not to get destroyed on the first error by setting EM::Connection#send_error_handling=mode (cabo).
• EM::attach_server added (ramonmaruko).
• EM::RestartableTimer added (adzap).
• EM::get_max_timers and EM::set_max_timers are removed (they still exist but do nothing). This solves the annoying "RuntimeError: max timers exceeded" exception.
• Support for Enumerable in EM::Iterator (fl00r).
• Improvements to EM::Protocols::LineProtocol and have it autoload (gaffneyc).
• EM::Protocols::SmtpServer: support multiple messages per one connection and login auth type (bogdan).
• Reimplement EM::Queue to avoid shift/push performance problem (grddev).
• Many code cleanups.
• New EM::Connection option for start_tls() method: :ssl_version (valid values are :SSLv23, :SSLv3 and :TLSv1, default value is :SSLv23).
• New EM::Connection option for start_tls() method: :cipher_list (valid values are any OpenSSL cipher string, default value is "ALL:!ADH:!LOW:!EXP:!DES-CBC3-SHA:@STRENGTH").

Installation

Install the current stable version of EventMachine-LE:

gem install eventmachine-le

If you want the last beta version (not fully tested) install it by using --pre option:

gem install eventmachine-le --pre

Usage

Using EventMachine-LE within your project just requires loading it as follows:

# First load EventMachine-LE.
require "eventmachine-le"

# NOTE: It does not hurt to call "require 'eventmachine'" later
# (it has no effect at all).

# Then load any other Ruby Gem depending on EventMachine so it
# will use EventMachine-LE.
require "em-udns"

By doing this, you will avoid conflicts with the main EventMachine Gem (if it's also installed).

Authors

This branch is mantained by Carsten Bormann and Iñaki Baz Castillo.