Daniel Kahn Gillmor <dkg@fifthhorseman.net> writes:
> i think the command would be "notmuch gpg", not "gpg-notmuch" -- in your
> configuration, how does emacs know to invoke notmuch on the remote
> server instead of locally?

notmuch on my local machine is a shell script that executes notmuch on
my server via ssh, as per http://notmuchmail.org/remoteusage/. The
reason why this works is that there is no meaning for it to ever execute
locally - there is no notmuch database locally. So from the perspective
of emacs, it might as well be running on the same computer as notmuch
is. Having notmuch-emacs execute shell commands is really nice for this
- because they can easily be replaced with versions that run commands on
other hosts. 

> is it possible that we could make this change something that happens
> in exactly one place in the emacs configuration, and have the wrapper
> scripts figure out the rest?

I think so - signing/encrypting is done via message-mode, so it could be
configured separately (as this should probably always happen locally,
and certainly shouldn't be forced to happen in the same place as the
email store). So if there were a setting like:

(setq notmuch-gpg-command "/path/to/gpg-or-wrapper")

That was what notmuch-emacs used to fetch keys (and anything else it
needed to do), I think it would work.