Custom naming for previous requirements hash file

[dgilland]

For some of my tox projects, I use a single virtualenv for all test commands. The config looks something like this:

[tox]
envlist = flake8, pylint, docs, unit

[testenv]
envdir = {toxworkdir}/env
deps =
    -rrequirements-test.txt
commands =
    flake8,lint,test: flake8
    pylint,lint,test: pylint
    docs: sphinx-build
    unit,test: pytest

So even though I have different tox environments, they all share the same virtualenv.

What I run into with tox-battery is that the initial tox build ends up recreating each tox env for a single run of $ tox because there doesn't exist a requirements.previous file yet for each of the envs. Subsequent runs are fine though. For my local dev side, this isn't too much of a problem; however, for CI servers, the build times are longer than they need to be due to the venv recreation since the CI build always starts with a fresh checkout.

My question is whether you would consider having an option to name the previous requirements file based on the actual venv path instead of the tox env name or possibly a setting under the env configuration that explicitly defines the name used in previous requirements file. Something like:

[testenv:flake8]
# would be used to build filename "requirements.txt.{tox_battery_basename}.previous"
tox_battery_basename = env

[testenv:pylint]
tox_battery_basename = env

and maybe a global option which would apply to all envs unless they overwrote the value in the env specific config:

[testenv]
tox_battery_basename = env

Thoughts? If you are open to this idea, I could submit a PR for it.

Thanks!

[signalpillar]

Hi Derrick ( @dgilland ), thank you for this well formed issue. It is a really interesting case that I've never considered myself and was happy to address.

As a result (PR #12 ) I managed to support case with custom envdir without modifying client's tox.ini file.

Could you please look review that PR and tell me whether it looks reasonable for you. Especially if you can give me advice how to improve description of file name format for .previous . I'll try to merge it this weekend after playing with it a bit.

Thank you!

[dgilland]

I don't really have any other suggestions on naming the .previous file. A hash of the envdir seems sufficient. Only downside is that it's not obvious which env it applies to if someone were to look at the files (not sure if that's even something to consider).

[signalpillar]

Yeah, that is true about file names, they are quite cryptic. From other side, I am not sure somebody has to read them. At least, so far. Thanks again for you review! I've addressed your latest finding.

[dgilland]

Awesome work! Thanks!

[signalpillar]

@dgilland thank you for you review and help.