Triggering relation events?

[Nick Barcet]

Hello,

I've been having fun during my week of vacation contributing a few 
charms and a ch_peer_copy function for charm-helpers [1] which allowed 
me to automatically copy the certificates and des_key that are in the 
"leader" unit of roundcube to all the other units [2].  This works great 
and shows the power of peer relations, but brings a small question:

Let's imagine that at some point in the future I need to update this 
certificate (let's say, when it expires).  I can upload the new certs to 
the machine using 'juju scp'.  I can update the configuration of my 
units using 'juju set'. My problem is how do I trigger a change even on 
all the peer relations so that the certificates are copied again?  I 
could not find any way to force an event in the doc.  Maybe I am taking 
the wrong approach to this?

[1] https://code.launchpad.net/~nijaba/charm-tools/peer-scp
[2] https://code.launchpad.net/~nijaba/charm/oneiric/roundcube/new-scp

Nick