... wherein I bloviate discursively

Brian Clapper,

eventter: A lightweight notification framework

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A short time ago, colleague and friend, Mark Chadwick, put together an interesting little Python tool he calls eventter. Basically, it’s a small API around a simple UDP broadcast messaging protocol. An eventter sending process emits a message, and all eventter listeners on the local network receive it.

If that were it, eventter wouldn’t be all that interesting. However, Mark wrote an example receiver that forwards any message it receives to DBUS. Run that receiver on a Linux machine under Gnome, and any message sent via the eventter framework shows up as a small, temporary Gnome notification.

I added two more sample receivers, one for Growl (for Mac OS X machines) and one for Snarl (for Windows machines). So the eventter distribution has adapters for Growl-like services on three major platforms.

“But what’s the point?” you ask. Well, we’ve actually found some interesting uses for eventter at the office. For instance:

  • Mark installed an eventter command client as a subversion post-commit hook. Now, whenever anyone commits anything to our source code repository, everyone running an eventter receiver sees the commit message for a few seconds.
  • I added a similar command line client to our CruiseControl continuous build server. Now, whenever a build completes, the name, version and status of the build (success or failure) are emitted via eventter.

I also modified my local copy of the Growl and DBUS receivers so they log received messages to a file. That way, I can quickly review what’s happened over the last hour or so, just by looking at that log file.

The UDP broadcast messages even propagate over our VPN, so someone working from home can still see them.

I’ve become rather fond of this tool. It’s simple, clean, well-written, easy to adapt, and surprisingly useful.