port kubetop to Python 3

[jason-kane]

pip3 install kubetop on 16.04 ubuntu leads to:

$ kubetop 
Traceback (most recent call last):
  File "/usr/local/bin/kubetop", line 7, in <module>
    from kubetop._script import main
  File "/usr/local/lib/python3.5/dist-packages/kubetop/_script.py", line 27, in <module>
    from ._textrenderer import Sink, kubetop
  File "/usr/local/lib/python3.5/dist-packages/kubetop/_textrenderer.py", line 114
    def _render_pod_top(reactor, (node_info, pod_info)):
                                 ^
SyntaxError: invalid syntax

[jason-kane]

ala PEP 3113
https://www.python.org/dev/peps/pep-3113/
http://twistedmatrix.com/trac/ticket/8346?cversion=1&cnum_hist=11

[exarkun]

Indeed. kubetop is currently Python 2-only. pip install kubetop (per the instructions in the README) will succeed.

Presumably there are more issues than just this syntax error preventing it from running on Python 3. For example, the txkube dependency is also Python 2-only. So porting that to Python 3 would be a first step to addressing this.

[gjcarneiro]

IMHO a new tool like kubetop should be Python 3 only from the start. Why bother with Python 2 in 2017?...

[exarkun]

IMHO a new tool like kubetop should be Python 3 only from the start. Why bother with Python 2 in 2017?...

I eagerly await your PR.

[rodrigc]

@jason-kane see these pull requests:

• Copy .travis.yml from txkube #50
• Replace map() + [], with list(map()) + [] #51
• Use twisted.python.compat.unicode since unicode is gone on Python 3 #52
• Remove tuple parameter unpacking which does not work on Python 3 #53
• Replace filter() with generator + join() #54
• sys.argv[0] is bytes on Python 2, and unicode on Python 3 #60

[jason-kane]

I opened the ticket but am not a kubetop developer so couldn't merge even if I knew the codebase well enough to adequately review. I think you want @exarkun.

[rodrigc]

I just wanted to let you know that things are in progress. exarkun will of course be doing the reviews and any merges.