Build a Python Executable (PEX)

Problem

You need to create an executable .pex Python binary (aka a "PEX") out of Python source code.

For more on PEX files see: https://github.com/pantsbuild/pex

If you need to create a Python library target instead, see Define a Python Library Target.

Solution

Define a python_binary target that you can build as a PEX using the binary goal:

$ ./pants binary src/python/myproject/example:my-python-binary

Discussion

In a python_ binary target, you should specify:

• A name for the PEX
• A source Python file that contains a main function
• A list of dependencies (optional). This list should include only Python library targets within the same project, not third-party dependencies. Any third-party dependencies should be specified in library targets.

Note: As an alternative to specifying a source file, you can define an entry_point function in your python_binary target. For example, specifying entry_point='main:run' would mean that the main function for the binary is the run() function contained in main.py.

Here's an example python_binary target:

python_library(
  name='myproject-lib',
  # Other parameters
)

python_binary(
  name='myproject-bin',
  source='main.py',
  dependencies=[
    ':myproject-lib',
  ],
)

See Also

• Run a Binary Target
• Define a Python Library Target