add xonsh support

[hall]

Mostly straightforward changes; not a xonsh or rust expert but it works on my machine 😄 a few notes to help explain why I did things the way I did:

• xonsh doesn't like the \e color escapes (but works fine with \033)
• xonsh runs in a python subprocess
• xonsh doesn't let users embed arbitrary commands into the prompt without first adding them to the PROMPT_FIELDS dict.

[sbstp]

Nice, thanks. In the other shells I've added hooks to constantly reset KUBECONFIG to the right value (the one in KUBIE_KUBECONFIG). This is done to avoid errors if someone or a tool does an export KUBECONFIG=... in a kubie shell. Is it something that can be implemented with xonsh?

[hall]

Ah, good catch! Yep, I've added that functionality now.

However, I'm only now realizing that the prompt doesn't actually get updated after initialization. I'll convert this to a draft until I figure that out.

[sbstp]

I tried your branch with xonsh, I got this error just after picking the context. I'm using Debian bullseye so the xonsh version is a tad behind, but not that much.

simon@debian ~/projects/kubie hall-xonsh $ $XONSH_SHOW_TRACEBACK = True
simon@debian ~/projects/kubie hall-xonsh $ kubie ctx
xonsh: To log full traceback to a file set: $XONSH_TRACEBACK_LOGFILE = <filename>
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/xonsh/__amalgam__.py", line 17922, in xonsh_script_run_control
    run_script_with_cache(filename, execer, ctx)
  File "/usr/lib/python3/dist-packages/xonsh/__amalgam__.py", line 3214, in run_script_with_cache
    ccode = compile_code(filename, code, execer, glb, loc, mode)
  File "/usr/lib/python3/dist-packages/xonsh/__amalgam__.py", line 3173, in compile_code
    ccode = execer.compile(code, glbs=glb, locs=loc, mode=mode, filename=filename)
  File "/usr/lib/python3/dist-packages/xonsh/__amalgam__.py", line 21438, in compile
    tree = self.parse(input, ctx, mode=mode, filename=filename, transform=transform)
  File "/usr/lib/python3/dist-packages/xonsh/__amalgam__.py", line 21398, in parse
    tree, input = self._parse_ctx_free(input, mode=mode, filename=filename)
  File "/usr/lib/python3/dist-packages/xonsh/__amalgam__.py", line 21522, in _parse_ctx_free
    tree = self.parser.parse(
  File "/usr/lib/python3/dist-packages/xonsh/parsers/base.py", line 497, in parse
    tree = self.parser.parse(input=s, lexer=self.lexer, debug=debug_level)
  File "/usr/lib/python3/dist-packages/ply/yacc.py", line 333, in parse
    return self.parseopt_notrack(input, lexer, debug, tracking, tokenfunc)
  File "/usr/lib/python3/dist-packages/ply/yacc.py", line 1120, in parseopt_notrack
    p.callable(pslice)
  File "/usr/lib/python3/dist-packages/xonsh/parsers/base.py", line 2253, in p_atom_expr
    p[0] = self.apply_trailers(p[1], p[2])
  File "/usr/lib/python3/dist-packages/xonsh/parsers/base.py", line 2247, in apply_trailers
    assert False
AssertionError
error running xonsh run control file '/tmp/kubie-xonshrcVUMSyd.xonsh': 
simon@debian ~/projects/kubie hall-xonsh $ xonsh --version
xonsh/0.9.25

[sbstp]

Let's hope not too many shells are made with Python 😄

[hall]

I figured we'd let them cross that bridge when they get here 😁 The alternative would probably be to, if python was detected, strip the interpreter and then reevaluate the remaining string as if it were the original command.

[sbstp]

Yeah we'll cross the bridge when we get to it

[sbstp]

Code looks good to me. It's just a matter of ironing out a few bugs I think.

[hall]

Interesting. You're only one patch version behind me (on nixos 21.05). I just tried the appimage from xonsh's repo (the 0.9.25 release --version flag actually returned xonsh/0.9.24.dev223 but 🤷 close enough) and still couldn't reproduce your error. Probably something different about our environments. I'll keep testing.

[sbstp]

I tried installing xonsh 0.10.1 with pipx, pipx install xonsh[full] but I don't see a custom prompt like in bash or zsh. Is it supposed to not have a prompt?

[hall]

It should update (prepend, by default) the prompt, yeah.

print($PROMPT)

Should have something like [{ctx}|{ns}] at the beginning.

[sbstp]

simon@debian ~/projects $ print($PROMPT)
{env_name}{BOLD_GREEN}{user}@{hostname}{BOLD_BLUE} {cwd}{branch_color}{curr_branch: {}}{RESET} {BOLD_BLUE}{prompt_end}{RESET}

I start in a bash shell first, then do xonsh to start a xonsh shell. Then I do kubie ctx and pick a context. I wonder if bash could be affecting things.

[hall]

Hm, I did xonsh -> bash -> xonsh --no-rc and the prompt was there. It should only not add the prompt if it's disabled in kubie's settings: https://github.com/sbstp/kubie/pull/84/files#diff-c27cd8b25abdaea337f9e4966c67aac8e4bb06a79f3fa7cbcd16840383ef18ddR39

It does it at the 3rd to last line in the generated file:

[k|default][23:07:53]  bryton@thinkpad ~ 
> cat /tmp/kubie-xonshrcegwXFe.xonsh | tail -n 3
    $PROMPT = $KUBIE_PROMPT + $PROMPT

del $KUBIE_PROMPT

[hall]

Alright -- I think I've fixed the AssertionError. I was able to reproduce with this Dockerfile:

FROM debian:bullseye

RUN apt update && \
    apt install -y \
        cargo \
        procps \
        vim \
        xonsh

WORKDIR /app
COPY Cargo.toml Cargo.lock ./
COPY src src
RUN cargo install --path .

ENV PATH /root/.cargo/bin:$PATH

ENTRYPOINT xonsh

then

> docker build -t kubie-debug .
. . .
> docker run -it --rm  -v $HOME/.kube:/root/.kube kubie-debug

and, once inside the container

kubie ctx <context>

For some reason, it didn't like the array index notation so I just replaced that with a call to pop() 🤷 let me know if that fixes it on your end.

[hall]

These changes have been working pretty well on my end; let me know if there's something else that needs fixed/updated before it can be merged.

[sbstp]

Yeah, sorry. I was under the assumption that the bug I found was still there.

[sbstp]

I re-tested it and it looks good so I will merge it.