Rust Projects

PyOxidizer uses Rust projects to build binaries embedding Python.

If you just have a standalone configuration file (such as when running pyoxidizer init-config-file), a temporary Rust project will be created as part of building binaries. That project will be built, its build artifacts copied, and the temporary project will be deleted.

If you use pyoxidizer init-rust-project to initialize a PyOxidizer application, the Rust project exists side-by-side with the PyOxidizer configuration file and can be modified like any other Rust project.


Generated Rust projects all have a similar layout:

$ find pyapp -type f | grep -v .git

The Cargo.toml file is the configuration file for the Rust project. Read more in the official Cargo documentation. The magic lines in this file to enable PyOxidizer are the following:

build = ""

pyembed = ...

These lines declare a dependency on the pyembed package, which holds the smarts for embedding Python in a binary.

In addition, the build = "" tells runs a script that hooks up the output of the pyembed crate with this project.

Next let’s look at src/ If you aren’t familiar with Rust projects, the src/ file is the default location for the source file implementing an executable. If we open that file, we see a fn main() { line, which declares the main function for our executable. The file is relatively straightforward. We import some symbols from the pyembed crate. We then construct a config object, use that to construct a Python interpreter, then we run the interpreter and pass its exit code to exit(). Succinctly, we instantiate and run an embedded Python interpreter. That’s our executable.

The pyoxidizer.bzl is our auto-generated PyOxidizer configuration file.