isort

Bazel rules for the Python formatter isort.

Setup

First ensure rules_venv is setup by referring to rules_venv setup.

Next, the rules_venv rules work mostly off of toolchains which are used to provide the necessary python targets (aka isort) for the process wrappers. Users will want to make sure they have a way to get the necessary python dependencies. Tools such as req-compile can provide these.

With the appropriate dependencies available, a py_isort_toolchain will need to be configured:

load("@rules_venv//python/isort:defs.bzl", "py_isort_toolchain")

py_isort_toolchain(
    name = "toolchain_impl",
    isort = "@pip_deps//:isort",
    visibility = ["//visibility:public"]
)

toolchain(
    name = "toolchain",
    toolchain = ":toolchain_impl",
    toolchain_type = "@rules_venv//python/isort:toolchain_type",
    visibility = ["//visibility:public"]
)

This toolchain then needs to be registered in the MODULE.bazel file.

register_toolchains("//tools/python/isort:toolchain")

Usage

Python code can be formatted using the following command:

bazel run @rules_venv//python/isort

In addition to this formatter, a check can be added to bazel build invocations using the py_isort_aspect aspect. Simply add the following to a .bazelrc file to enable this check.

build --aspects=@rules_venv//python/isort:defs.bzl%py_isort_aspect
build --output_groups=+py_isort_checks

Sections and Ordering

Of all isort sections, FIRSTPARTY and THIRDPARTY follow unique rules to ensure ordering makes sense on a per-target basis.

First party

Direct source dependencies passed to the srcs attribute.
Repository relative packages.

Third party

Other py_* targets (the deps attribute). Note that deps which use repo absolute import paths will be considered first party.

Tips

Isort is sensitive to the legacy_create_init attribute on python rules. For more correct and consistent behavior, this value should always be 0 or if the default of -1 is set, the --incompatible_default_to_explicit_init_py flag should be added to the workspace's .bazelrc file to ensure the behavior is disabled.

Aspects

py_isort_aspect

py_isort_test

load("@rules_venv//python/isort:defs.bzl", "py_isort_test")

py_isort_test(name, config, target)

A rule for running isort on a Python target.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
config	The config file (isort.cfg) containing isort settings.	Label	optional	`"@rules_venv//python/isort:config"`
target	The target to run `isort` on.	Label	required

py_isort_toolchain

load("@rules_venv//python/isort:defs.bzl", "py_isort_toolchain")

py_isort_toolchain(name, isort)

A toolchain for the isort formatter rules.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
isort	The isort `py_library` to use with the rules.	Label	required

py_isort_aspect

load("@rules_venv//python/isort:defs.bzl", "py_isort_aspect")

py_isort_aspect()

An aspect for running isort on targets with Python sources.

ASPECT ATTRIBUTES

ATTRIBUTES