Handle irc.wikimedia.org with caution. Interruption in this service will cause projects to suffer damage in the form of vandalism that will go largely unrecovered or cost significant volunteer efforts to fix retroactively.
irc.wikimedia.org runs on IRCD, providing recent changes feeds on IRC for every Wikimedia wiki. Normal users cannot speak nor create channels, see m:IRC for information about Wikimedia's discussion channels.
The service is currently hosted on irc001.wikimedia.org. Events are broadcasted to both servers but the irc.wikimedia.org CNAME is only pointed to one server and needs to be switched manually if the active ones goes down.
We now have a a vastly superior EventStreams service providing machine-readable push notifications over HTTP in JSON format at https://stream.wikimedia.org/v2/stream/recentchange, but until the key consumers of the IRC recent changes feed have migrated, this old service remains vital.
Its practical use ranges widely. From relatively low impact services, such as:
- pretty monitors (e.g. wikistream)
- edit bots that react to edits as they happen (e.g. bots that sign unsigned talk page contributions by anons)
... to much higher impact services:
- Countervandalism auto-revert bots (e.g. ClueBot alone finds and reverts over 1,000 edits every day on en.wikipedia.org alone)
- Countervandalism Network patrol feeds (e.g. CVNBot, monitors our 100s of smaller wikis that don't have active patrol teams or watchers)
When irc.wikimedia.org is down:
- ClueBot will be interrupted and any edits happening during time will never be looked into by it. This is comparable to having the AbuseFilter extension down.
- Patrollers (using RTRC, or Huggle, or STiKI) will not see the edits made during this time. This is comparable to having the recentchanges SQL table temporarily ignore all write actions and thus pretty much hide activity from reviewers.
While it is most unfortunate that we rely on a bot to undo vandalism that should probably be prevented before saving (e.g. some kind of hook in AbuseFilter to consult ClueBot, could be ran natively on the cluster perhaps one day), and it is most unfortunate that most of our patrolling efforts indirectly rely on irc.wikimedia.org, that is the reality and it is important that we know its impact and the kind of sensitive treatment it deserves.