config_settings

flag --//python/config_settings:python_version: Determines the default hermetic Python toolchain version. This can be set to one of the values that rules_python maintains.

flag --//python/config_settings:exec_tools_toolchain

Determines if the exec_tools_toolchain_type toolchain is enabled.

Note

Note that this only affects the rules_python generated toolchains.

Values:

enabled: Allow matching of the registered toolchains at build time.
disabled: Prevent the toolchain from being matched at build time.

Added in version 0.33.2.

flag --//python/config_settings:precompile

Determines if Python source files should be compiled at build time.

Note

The flag value is overridden by the target level precompile attribute, except for the case of force_enabled and forced_disabled.

Values:

auto: Automatically decide the effective value based on environment, target platform, etc.
enabled: Compile Python source files at build time. Note that --precompile_add_to_runfiles affects how the compiled files are included into a downstream binary.
disabled: Don’t compile Python source files at build time.
if_generated_source: Compile Python source files, but only if they’re a generated file.
force_enabled: Like enabled, except overrides target-level setting. This is mostly useful for development, testing enabling precompilation more broadly, or as an escape hatch if build-time compiling is not available.
force_disabled: Like disabled, except overrides target-level setting. This is useful useful for development, testing enabling precompilation more broadly, or as an escape hatch if build-time compiling is not available.

Added in version 0.33.0.

flag --//python/config_settings:precompile_source_retention

Determines, when a source file is compiled, if the source file is kept in the resulting output or not.

Note

This flag is overridden by the target level precompile_source_retention attribute.

Values:

keep_source: Include the original Python source.
omit_source: Don’t include the orignal py source.
omit_if_generated_source: Keep the original source if it’s a regular source file, but omit it if it’s a generated file.

Added in version 0.33.0.

flag --//python/config_settings:precompile_add_to_runfiles

Determines if a target adds its compiled files to its runfiles.

When a target compiles its files, but doesn’t add them to its own runfiles, it relies on a downstream target to retrieve them from PyInfo.transitive_pyc_files

Values:

always: Always include the compiled files in the target’s runfiles.
decided_elsewhere: Don’t include the compiled files in the target’s runfiles; they are still added to PyInfo.transitive_pyc_files. See also: py_binary.pyc_collection attribute. This is useful for allowing incrementally enabling precompilation on a per-binary basis.

Added in version 0.33.0.

flag --//python/config_settings:pyc_collection

Determine if py_binary collects transitive pyc files.

Note

This flag is overridden by the target level pyc_collection attribute.

Values:

include_pyc: Include PyInfo.transitive_pyc_files as part of the binary.
disabled: Don’t include PyInfo.transitive_pyc_files as part of the binary.

Added in version 0.33.0.

flag --//python/config_settings:py_linux_libc

Set what libc is used for the target platform. This will affect which whl binaries will be pulled and what toolchain will be auto-detected. Currently rules_python only supplies toolchains compatible with glibc.

Values:

glibc: Use glibc, default.
muslc: Use muslc.

Added in version 0.33.0.

flag --//python/config_settings:pip_whl

Set what distributions are used in the pip integration.

Values:

auto: Prefer whl distributions if they are compatible with a target platform, but fallback to sdist. This is the default.
only: Only use whl distributions and error out if it is not available.
no: Only use sdist distributions. The wheels will be built non-hermetically in the whl_library repository rule.

Added in version 0.33.0.

flag --//python/config_settings:pip_whl_osx_arch

Set what wheel types we should prefer when building on the OSX platform.

Values:

arch: Prefer architecture specific wheels.
universal: Prefer universal wheels that usually are bigger and contain binaries for both, Intel and ARM architectures in the same wheel.

Added in version 0.33.0.

flag --//python/config_settings:pip_whl_glibc_version

Set the minimum glibc version that the py_binary using whl distributions from a PyPI index should support.

Values:

"": Select the lowest available version of each wheel giving you the maximum compatibility. This is the default.
X.Y: The string representation of a glibc version. The allowed values depend on the requirements.txt lock file contents.

Added in version 0.33.0.

flag --//python/config_settings:pip_whl_muslc_version

Set the minimum muslc version that the py_binary using whl distributions from a PyPI index should support.

Values:

"": Select the lowest available version of each wheel giving you the maximum compatibility. This is the default.
X.Y: The string representation of a muslc version. The allowed values depend on the requirements.txt lock file contents.

Added in version 0.33.0.

flag --//python/config_settings:pip_whl_osx_version

Set the minimum osx version that the py_binary using whl distributions from a PyPI index should support.

Values:

"": Select the lowest available version of each wheel giving you the maximum compatibility. This is the default.
X.Y: The string representation of the MacOS version. The allowed values depend on the requirements.txt lock file contents.

Added in version 0.33.0.

flag --//python/config_settings:bootstrap_impl

Determine how programs implement their startup process.

Values:

system_python: Use a bootstrap that requires a system Python available in order to start programs. This requires PyRuntimeInfo.bootstrap_template to be a Python program.
script: Use a bootstrap that uses an arbitrary executable script (usually a shell script) instead of requiring it be a Python program.

Note

The script bootstrap requires the toolchain to provide the PyRuntimeInfo provider from rules_python. This loosely translates to using Bazel 7+ with a toolchain created by rules_python. Most notably, WORKSPACE builds default to using a legacy toolchain built into Bazel itself which doesn’t support the script bootstrap. If not available, the system_python bootstrap will be used instead.