Python 3 transition #215
Python 3 transition #215
Conversation
|
@okalachev, this P/R drops ROS support for Python 2 completely (for reasons stated elsewhere). |
builder/assets/butterfly.service
Outdated
| @@ -2,5 +2,5 @@ | |||
| Description=Butterfly Terminal Server | |||
|
|
|||
| [Service] | |||
| ExecStart=/usr/local/bin/butterfly.server.py --host="0.0.0.0" --unsecure | |||
| ExecStart=/bin/bash -c ". /root/butterfly_env/bin/activate; butterfly.server.py --host="0.0.0.0" --unsecure" | |||
There was a problem hiding this comment.
Wouldn't it be better to just use Python 2 for Butterly?
There was a problem hiding this comment.
Might be, though I'd really like to keep as little of Python 2 as possible. In fact, we could probably just use a lower version of Tornado for Butterfly, it shouldn't cause any problems.
There was a problem hiding this comment.
I've restored system-wide butterfly installation, it should work with Tornado 4.2.1.
| @@ -17,6 +17,8 @@ | |||
| from clover.srv import GetTelemetry, Navigate, NavigateGlobal, SetPosition, SetVelocity, \ | |||
| SetAttitude, SetRates, SetLEDEffect | |||
|
|
|||
| get_telemetry = rospy.ServiceProxy('get_telemetry', GetTelemetry) | |||
There was a problem hiding this comment.
Picked this from #154, which "contained useful code" (your own words!)
There was a problem hiding this comment.
OK :) Когда это в виде изменения, бросилось в глаза.
builder/test/tests.sh
Outdated
| @@ -20,14 +20,16 @@ nmap --version | |||
| lsof -v | |||
| git --version | |||
| vim --version | |||
| pip --version | |||
There was a problem hiding this comment.
Depends on how much Pyhton2 we wish to keep. I could re-add pip for Python 2, but what would be the rationale? It's not like our users are going to be able to use Python 2 in any meaningful way.
There was a problem hiding this comment.
It's possible to write and run normal programs (even without ROS), right? It looks like a meaningful way. For older programs, for example.
There was a problem hiding this comment.
Okay, I've added installing pip for Python 2 back. pip will still default to pip3, users will still be able to use pip2 for Python 2 packages.
|
Regarding |
|
Regarding our failing (native) tests: Looks like we need to use some hacks to be both Python2- and Python3-compatible. The ROS way is to use Python2 shebangs (
Using install space is a no-go (at least in my opinion), at the very least this will make changing |
This may break rosdep down the line, but it seems to call `pip3` explicitly
Tests executed by ros_pytest are not meant to have shebangs anyway.
This reverts commit 6b9d90d. Newer dynamic_reconfigure uses PYTHON_EXECUTABLE CMake substitution, eliminating the need for a shebang (or a trampoline).
This shebang will be ignored with newer dynamic_reconfigure packages, and its presence should allow builds to succeed when older dynamic_reconfigure is used.
|
Work goes in #327. |
(I am not comfortable even opening this P/R, but I guess we should do this eventually)
As of 2020, Python 2 is no longer maintained. Package registries are working for now, but new software should use Python 3 instead.
This is concerning for us, since Clever (Clover?) is an educational platform, and teaching how to use deprecated tools is not our goal. As such, we are transitioning to Python 3.
This transition is somewhat complicated:
I've done some preparations for Python 3 (for example, I've built our dependencies against it, patching as required). There are still some issues to be resolved, though:
Butterfly should be running from a virtual environment (may be resolved by patching(UPDATE: May be worked around by using an olderrosbridge_suite)tornadoversion) Butterfly runs like before, it just uses an older Tornado version;rosbridge_suitedoes not work with Python 3 (UPDATE: Should be fixed by Python 3 updates/fixes RobotWebTools/rosbridge_suite#460) (UPDATE 2: We are using a patched build that should work);cv_bridgeseems to work after applying these patches: Python 3 compatibility (Melodic) ros-perception/vision_opencv#312;python-opencvis not getting installed (since it's not required anywhere)python-opencvis installed explicitly;native tests are failing because ofAll tests now use#!/usr/bin/env python3shebangsros_pytest, which selects the correct interpreter automatically;printstatements in Python)This is still a work-in-progress, but we should perform regular builds from this branch and try using them. This needs to be thoroughly tested before merge.