If you pass --tor-control-port= and we can't use it, throw an error that will
kill the whole process, instead of falling back to the default SOCKS port.
If you omit --tor-control-port=, then if all default control port connections
fail, we'll fall back to the default SOCKS port.
Also, test each combination separately, and improve the status messages.
This shifts most reponsibility to the new txtorcon "Controller" object, where
it belongs. We no longer need a list of likely control-port locations, nor do
we need to keep track of the SOCKS port ourselves.
The one downside is that if a control-port is not reachable, then this does
not fall back to using a plain SOCKS port (usually tcp:localhost:9050).
txtorcon no longer uses txsocksx, so it no longer advertises a simple way to
use Tor without the control port. This shouldn't affect users who run the
TorBrowserBundle, or who are running a tor daemon which they can control
directly, but it may break for users who want to use a pre-existing tor
daemon that they don't have permissions to speak control-port to.
The new TorManager adds --launch-tor and --tor-control-port= arguments
(requiring the user to explicitly request a new Tor process, if that's what
they want). The default (when --tor is enabled) looks for a control port in
the usual places (/var/run/tor/control, localhost:9051, localhost:9151), then
falls back to hoping there's a SOCKS port in the usual
place (localhost:9050). (closes#64)
The ssh utilities should now accept the same tor arguments as ordinary
send/receive commands. There are now full tests for TorManager, and basic
tests for how send/receive use it. (closes#97)
Note that Tor is only supported on python2.7 for now, since txsocksx (and
therefore txtorcon) doesn't work on py3. You need to do "pip install
magic-wormhole[tor]" to get Tor support, and that will get you an inscrutable
error on py3 (referencing vcversioner, "install_requires must be a string or
list of strings", and "int object not iterable").
To run tests, you must install with the [dev] extra (to get "mock" and other
libraries). Our setup.py only includes "txtorcon" in the [dev] extra when on
py2, not on py3. Unit tests tolerate the lack of txtorcon (they mock out
everything txtorcon would provide), so they should provide the same coverage
on both py2 and py3.
