Plugin Question about updating from explicit constraints to the resolved lockfiles: I'm trying to update our pants-docker plugin to install pip dependencies into a virtual-env (in the docker container) previously I would get the

PythonSetup.requirement_constraints

to find the lockfile & copy that into the docker image, and then emit a pip install command using the constraints. I think I can do the same thing with the resolved lock files(s) but... I'm not sure how to get the name/contents of that file? I can find the normalized_value of

PythonRequirementResolveField

but unless it's specified (I think?) it just is 'python-default'? should I just hardcode something in there? or... something? idk? is there.. an example how pex installs pip stuff? Also very open to the idea that i'm totally barking up the wrong tree! thanks!

Hi! Sorry for the delay, Nate! How many lockfiles are you currently using? If n == 1, this becomes much easier

right now it's one but we do have medium term plans to pull in another project to this repo! (I am going to upgrade as far as I can without worring about this so hopefully later today I can get to where this breaks) @hundreds-father-404 no worries about the delay!

Okay. The easiest migration path is to look up

PythonSubsystem.resolves

to get the path to your

n == 1

lockfile. Then treat it like you treated constraints.txt I recommend adding an AssertionError if n > 1, so that you know to redo this plugin when you have multiple resolves

rad that seems like a path forward!

are you using Pex lockfiles? Is that going to mess you up that it's not requirements-txt style? Generally, you can invoke

pex3 lock export

by using Pex directly to convert to requirements.txt, although it's a lossy operation

although it's a lossy operation

I think the main challenge is platform-agnosticism. Pex lockfiles work with multiple platforms, whereas I want to say

pex3 lock export

only works with the specified platform (defaulting to current). You may want to specify

--platform

to Pex

hmmmm I would prefer to use requirements.txt style lockfiles so I can emit:

pip install package==xyz -c lockfile.txt

into my dockerfile?

until Pants 2.15, you can use Pex as the lockfile generator via

[python].lockfile_generator

. But it has several issues, including sometimes issues with nonsensical environment markers for transitive deps, and not supporting

[python-repos]

sorry not totally up on... how a a pex lockfile works but it currently seems compatible enough? is my alternative to set

PANTS_GENERATE_LOCKFILES_CUSTOM_COMMAND

to use pip-compile to generate something?

I wouldn't expect

pip install

to work with it.. is

default.lock

a JSON file?

my pants.toml just has 'enable_resolves=true' and my default.lock looks like this:

ansicolors==1.1.8
attrs==22.1.0; python_version >= "3.7"
certifi==2022.9.24; python_version >= "3.7" and python_version < "4"

ah yeah, 2.11 I think still uses Poetry by default because Pex was too immature

hmmm so I guess fundamentally I want to install all these packages into a docker image, with all of the transitive dependencies set to a pinned version, right now we generate a constraints file with pip-compile, I guess I'm gonna read over the 3rd party dependencies stuff to see what our options are

bump that you can use Pex to export into a requirements.txt style file, with every transitive dep pinned and with

--hash

ok - sorry I wasn't following above, I think that makes sense I'll let you know if I have other questions