Package: nox-poetry
nox-poetryUsePoetryinsideNoxsessionsThis package provides a drop-in replacement for thenox.sessiondecorator,
and for thenox.Sessionobject passed to user-defined session functions.
This enablessession.installto install packages at the versions specified in the Poetry lock file.fromnox_poetryimportsession@session(python=["3.10","3.9"])deftests(session):session.install("pytest",".")session.run("pytest")Disclaimer:This project is not affiliated with Nox, and not an official Nox plugin.InstallationInstallnox-poetryfrom the Python Package Index:$pipinstallnox-poetryImportant:This package must be installed into the same environment that Nox is run from.
If you installed Nox usingpipx,
use the following command to install this package into the same environment:$pipxinjectnoxnox-poetryRequirementsPython 3.7+Poetry >= 1.0.0You need to have a Poetry installation on your system.nox-poetryuses Poetry via its command-line interface.UsageImport the@sessiondecorator fromnox_poetryinstead ofnox.
There is nothing else you need to do.
Thesession.installmethod automatically honors the Poetry lock file when installing dependencies.
This allows you to manage packages used in Nox sessions as development dependencies in Poetry.This works because session functions are passed instances ofnox_poetry.Session,
a proxy fornox.Sessionadding Poetry-related functionality.
Behind the scenes, nox-poetry uses Poetry to export aconstraints fileand build the package.For more fine-grained control, additional utilities are available under thesession.poetryattribute:session.poetry.installroot(distribution_format=["wheel"|"sdist"])session.poetry.build_package(distribution_format=["wheel"|"sdist"])session.poetry.export_requirements()Note thatdistribution_formatis akeyword-only parameter.Here is a comparison of the different installation methods:Usesession.install(...)to install specific development dependencies, e.g.session.install("pytest").Usesession.install(".")(orsession.poetry.installroot()) to install your own package.Usesession.run_always("poetry", "install", external=True)to install your package withalldevelopment dependencies.Please read the next section for the tradeoffs of each method.Why?Let's look at an example:fromnox_poetryimportsession@session(python=["3.10","3.9"])deftests(session):session.install("pytest",".")session.run("pytest")This session performs the following steps:Build a wheel from the local package.Install the wheel as well as thepytestpackage.Invokepytestto run the test suite against the installation.Consider what would happen in this session
if we had imported@sessionfromnoxinstead ofnox_poetry:Package dependencies would only be constrained by the wheel metadata, not by the lock file.
In other words, their versions would not bepinned.Thepytestdependency would not be constrained at all.Poetry would be installed as a build backend every time.Unpinned dependencies mean that your checks are not reproducible and deterministic,
which can lead to surprises in Continuous Integration and when collaborating with others.
You can solve these issues by declaringpytestas a development dependency,
and installing your package and its dependencies usingpoetry install:@nox.sessiondeftests(session:Session)->None:"""Run the test suite."""session.run_always("poetry","install",external=True)session.run("pytest")Unfortunately, this approach comes with its own set of problems:Checks run against an editable installation of your package,
i.e. your local copy of the code, instead of the installed wheel your users see.
In the best case, any mistakes will still be caught during Continuous Integration.
In the worst case, you publish a buggy release because you forgot to commit some changes.The package is installed, as well as all of its core and development dependencies,
no matter which tools a session actually runs.
Code formatters or linters, for example, don't need your package installed at all.
Besides being wasteful, it goes against the idea of running checks in isolated environments.nox-poetryuses a third approach:Installations are performed by pip, via thesession.installmethod.When installing your own package, Poetry is used to build a wheel, which is passed to pip.When installing third-party packages, Poetry is used to export aconstraints file,
which is passed to pip along with the packages.
The constraints file ensures that package versions are pinned by the lock file,
without forcing an installation of every listed dependency and sub-dependency.In summary, this approach brings the following advantages:You can manage tools likepytestas development dependencies in Poetry.Dependencies are pinned by Poetry's lock file, making checks predictable and deterministic.You can run checks against an installed wheel, instead of your local copy of the code.Every tool can run in an isolated environment with minimal dependencies.No need to install your package with all its dependencies if all you need is some linter.ContributingContributions are very welcome.
To learn more, see theContributor Guide.LicenseDistributed under the terms of theMIT license,nox-poetryis free and open source software.IssuesIf you encounter any problems,
pleasefile an issuealong with a detailed description.CreditsThis project was generated from@cjolowicz'sHypermodern Python Cookiecuttertemplate.