Python 3 Compatibility

[peternewman]

if i try the simple fade example this does not work:
stefan:~/ola/python/examples[master]$ python3 ./ola_simple_fade.py
Traceback (most recent call last):
File "./ola_simple_fade.py", line 69, in
wrapper.AddEvent(SHUTDOWN_INTERVAL, wrapper.Stop)
File "/home/stefan/ola/python/ola/ClientWrapper.py", line 287, in AddEvent
self._ss.AddEvent(time_in_ms, callback)
File "/home/stefan/ola/python/ola/ClientWrapper.py", line 215, in AddEvent
heapq.heappush(self._events, event)
TypeError: unorderable types: _Event() < _Event()

See:
https://groups.google.com/d/msg/open-lighting/7TuvU0T1CAo/0hBbXHw8BgAJ
https://groups.google.com/d/msg/open-lighting/7TuvU0T1CAo/oVIYBMk8BgAJ

Hopefully whoever takes on that will give the whole system a bit of a shakedown on Python 3 and fix any further remaining bugs.

[peternewman]

See also #1514

[peternewman]

And #1537 / #1538

[brucelowekamp]

I ran into this problem b/c my first attempt to use ola was on a mac with homebrew (btw, thanks, having great fun with ola), and mac homebrew builds it against python 3.

I actually considered whether it would be possible to fix the formula to use python2, but it would require a py2 build of protobuf3.6, which given python 2 is going unsupported (https://pythonclock.org/) etc seemed like it might be hard to get approved (though just copying the python code over works, of course)

I have a local build with #1538 applied that resolved the problems, though as I'm deploying on a RPi I forced everything back to py2 after awhile anyway. Regardless +1 for getting the py3 compatibility shipped. Do agree with the comments on #1538 about the need for more tests especially if intention is to ship both py2 and py3 for awhile. I might be able to devote a bit of time to some of that in the next couple of months, if needed.

[peternewman]

I ran into this problem b/c my first attempt to use ola was on a mac with homebrew (btw, thanks, having great fun with ola), and mac homebrew builds it against python 3.

Yeah I think I twigged that recently while digging into the protobuf changes they'd made to our formula. As an actual user of our Homebrew formula, would you be interested in maintaining it/updating it in future when we cut new releases? Having to do that and MacPorts when my only Mac access is via SSH to an OLP one is a bit of a pain, and takes time away from actual development.

I actually considered whether it would be possible to fix the formula to use python2, but it would require a py2 build of protobuf3.6, which given python 2 is going unsupported (https://pythonclock.org/) etc seemed like it might be hard to get approved (though just copying the python code over works, of course)

Likewise our CI is struggling with the Protobuf changes, you can see some of my attempts to fix it in #1584 .

I have a local build with #1538 applied that resolved the problems, though as I'm deploying on a RPi I forced everything back to py2 after awhile anyway. Regardless +1 for getting the py3 compatibility shipped. Do agree with the comments on #1538 about the need for more tests especially if intention is to ship both py2 and py3 for awhile. I might be able to devote a bit of time to some of that in the next couple of months, if needed.

Yeah that would be appreciated, I don't know if @nils-van-zuijlen has been tied up with life too, but if they don't have time or don't want to add the tests then getting someone else to do so would be good.

[Keeper-of-the-Keys]

I don't mind having a crack at porting stuff to python3 however I have never truly used the python scripts or bindings in a meaningful way so I would need to have some defined test setup, what to run etc.