Expand description

Control an embedded Python interpreter.

The pyembed crate contains functionality for controlling an embedded Python interpreter running in the current process.

pyembed provides additional functionality over what is covered by the official Embedding Python in Another Application docs and provided by the CPython C API. For example, pyembed can utilize a custom Python meta path importer that can import Python module bytecode from memory using 0-copy.

This crate was initially designed for and is maintained as part of the PyOxidizer project. However, the crate is generic and can be used outside the PyOxidizer project.

The most important types in this crate are OxidizedPythonInterpreterConfig and MainPythonInterpreter. An OxidizedPythonInterpreterConfig defines how a Python interpreter is to behave. A MainPythonInterpreter creates and manages that interpreter and serves as a high-level interface for running code in the interpreter.


Under the hood, pyembed makes direct use of the pyo3 crate for low-level Python FFI bindings as well as higher-level interfacing.

It is an explicit goal of this crate to rely on as few external dependencies as possible. This is because we want to minimize bloat in produced binaries.


The optional allocator-jemalloc feature controls support for using jemalloc as Python’s memory allocator. Use of Jemalloc from Python is a run-time configuration option controlled by the OxidizedPythonInterpreterConfig type and having jemalloc compiled into the binary does not mean it is being used!

The optional allocator-mimalloc feature controls support for using mimalloc as Python’s memory allocator. The feature behaves similarly to jemalloc, which is documented above.

The optional allocator-snmalloc feature controls support for using snmalloc as Python’s memory allocator. The feature behaves similarly to jemalloc, which is documented above.

The optional serialization feature controls whether configuration types (such as OxidizedPythonInterpreterConfig) implement Serialize and Deserialize.


Technical Implementation Notes


Defines a Python extension module and its initialization function.

Manages an embedded Python interpreter.

Configuration for a Python interpreter.

Holds configuration of a Python interpreter.

Represents a custom memory allocator that can be registered with Python.

Defines Python resources available for import.

An OxidizedPythonInterpreterConfig that has fields resolved.


Name of the Python memory allocators.

An optimization level for Python bytecode.

Defines what to do when comparing bytes or bytesarray with str or comparing bytes with int.

Control the validation behavior of hash-based .pyc files.

Holds values for coerce_c_locale.

Defines a backend for a memory allocator.

Defines how to call multiprocessing.set_start_method() when multiprocessing is imported.

Represents an error encountered when creating an embedded Python interpreter.

A source for packed resources data.

Defines the profile to use to configure a Python interpreter.

Defines terminfo database resolution semantics.