Version: 2.4 (deprecated)

Backends

How to enable specific functionality.

Pants has some basic, non-language-specific functionality built in to its core. For example, you can count the lines of code under some directory in your repo:

Bash
$ ./pants count-loc 'src/**'
───────────────────────────────────────────────────────────────────────────────
Language                 Files     Lines   Blanks  Comments     Code Complexity
───────────────────────────────────────────────────────────────────────────────
Python                      13       155       50        22       83          5
BASH                         2       261       29        22      210         10
JSON                         2        25        0         0       25          0
...

However most Pants functionality, including all language-specific functionality, is provided via backends.

A backend is a Python package that implements some required functionality, and uses hooks to register itself with Pants. You enable a backend by listing it under the backend_packages config key in pants.toml.

For example, to enable Python support:

pants.toml
[GLOBAL]
backend_packages = ["pants.backend.python"]

Available backends

Activate by adding the backend to the option backend_packages in the [GLOBAL] scope in pants.toml.

Backend	What it does	Docs
`pants.backend.awslambda.python`	Enables generating an AWS Lambda zip file from Python code.	Python support
`pants.backend.codegen.protobuf.python`	Enables generating Python from Protocol Buffers. Includes gRPC support.	Protobuf and gRPC
`pants.backend.python`	Core Python support.	Enabling Python support
`pants.backend.python.mixed_interpreter_constraints`	Adds the `py-constraints` goal for insights on Python interpreter constraints.	Interpreter compatibility
`pants.backend.python.lint.bandit`	Enables Bandit, the Python security linter: https://bandit.readthedocs.io/en/latest/.	Linters and formatters
`pants.backend.python.lint.black`	Enables Black, the Python autoformatter: https://black.readthedocs.io/en/stable/.	Linters and formatters
`pants.backend.python.lint.docformatter`	Enables Docformatter, the Python docstring autoformatter: https://github.com/myint/docformatter.	Linters and formatters
`pants.backend.python.lint.flake8`	Enables Flake8, the Python linter: https://flake8.pycqa.org/en/latest/.	Linters and formatters
`pants.backend.python.lint.isort`	Enables isort, the Python import autoformatter: https://timothycrosley.github.io/isort/.	Linters and formatters
`pants.backend.python.lint.pylint`	Enables Pylint, the Python linter: https://www.pylint.org.	Linters and formatters
`pants.backend.python.typecheck.mypy`	Enables MyPy, the Python type checker: https://mypy.readthedocs.io/en/stable/.	typecheck

Available backends​

Available backends