ircd

A hot-swappable, non-compliant IRCd.

Hot-swappable in the sense that you can update the server code while it's running without disconnecting any users.

RFC compliance is not a goal, neither in completeness nor in correctness. This IRCd is inspired by the late MSN chat server, and most notably implements the following features:

Two different users can login with the same nick simultaneously. This allows a user to access multiple channels via different browser pages (and thus multiple connections). PRIVMSGs to a certain nick will reach all users with that nick.
The authentication process is very strict, and nick changes are not allowed.
There's an additional channel/user mode, +q (channel owner), which is stronger than channel operator.
Channel access control via the ACCESS command (see the IRCX draft in doc/).

Architecture

The listening endpoints (SockJS and plain TCP) are completely decoupled from the proper IRC server, and communicate with each other through a makeshift message queue implemented via blocking operations on redis lists.

All user and channel data is persisted in redis at all times; the server has to fetch and update the relevant data bits while processing each and every message from the client. That is pretty slow. Don't expect to process more than 100 messages per second with this IRCd.

                     tornado                                      irc
                    endpoints                redis               server
                  +-----------+         +-------------+       +----------+
 browsers   <---> |  sockjs   | <--+--> |  blpop mq   | <---> |  server  |
                  +-----------+    |    |             |       +----------+
                  +-----------+    |    |  chan/user  |            ^
irc clients <---> | tcp(6667) | <--+    |    data     | <----------+
                  +-----------+         +-------------+

Installation

Clone the repository:

git clone https://github.com/lessandro/ircd.git
cd ircd

Grab the dependencies:

redis-server
pip install -r requirements.txt

Configure:

vim config/config.py

Start the servers:

bin/runservers

The servers run inside supervisord.

See www/index.html for an example of a SockJS client.

Hotswapping

As long as the endpoints remain intact, you can hotswap the server by simply running bin/ctl restart kernel. This command tells supervisord to send a SIGTERM and then restart the server. No messages are dropped and the sighandler will let the server finish processing any current message before exiting the process.

# git pull or edit files
bin/ctl restart kernel

The bin/watch script detects changes in the source files and automaticaly restarts the server if the unit tests pass.

pip install pywatch
bin/watch

Supervisord ctl

Access the supervisord ctl with bin/ctl. Any parameters are forwarded to supervisorctl.

# to access the supervisorctl cli
bin/ctl

# just print the status and exit
bin/ctl status

# stop everything
bin/ctl stop all
bin/ctl shutdown

# wipe the database
bin/flushdb

Testing

The unit tests use py.test and the code coverage plugin. You can run the tests with the command below, but if you're actively developing you should be using the watch script as described in the hotswapping section.

bin/runtests

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.