[tahoe-dev] upcoming compatibility bump

[Brian Warner]

I've been hacking on ticket #271 "implement new publish/subscribe
introduction scheme", and am ready to push the results to trunk. This patch
will change the way that the Introducer protocol works, which means nodes
running the new code wil be incompatible with nodes running the old code.
Specifically, the new introducer will not work with the old clients, or
vice-versa.

So each current test grid will experience a flag day when the introducer is
upgraded to run the new code. I'll be upgrading the public test grid (y3ee)
this afternoon. When I do, I'll be deleting the old introducer and creating a
brand-new one, to reduce confusion (i.e. prevent old clients from connecting
to the new introducer and speaking the wrong remote interface).

All the files from the old introducer will still be present. When you upgrade
your client code the new version, you just need to replace your
introducer.furl file with the new contents.

The new code also provides a "nickname" to the Introducer, which will be
displayed in various management tools, so feel free to write something unique
into $BASEDIR/nickname (like the hostname, or your name, or whatever). The
new scheme also makes it easier to not run a storage server: just touch
$BASEDIR/no_storage .

I'll send out mail later on today when I upgrade the test grid and replace
the old introducer.

cheers,
 -Brian