Relenv

Relenv creates re-producable and re-locatable python builds. The builds created with Relenv are re-producable in the sense that all binaries for the builds are built from source. These builds are re-locatable meaning you can move the root directory around on the filesystem.

Installing Relenv

pip install git+https://github.com/dwoz/Relenv.git

Pre-built Relenv Python Environments

Relenv can use pre-build Relenv Python environments.

python3 -m relenv fetch
python3 -m relenv create foo
foo/bin/pip3 install myproject

Building a Relenv Build

Currently building assumes your building on x86_64

Linux Dependencies

• make
• bison
• perl
• patchelf

Arch linux varients also require libxcrypt-compat

This should get fixed in the future.

Building on Linux

When using Relenv to create builds on linux you first need a toolchain. You can either build the toolchain or use a pre-built toolchain.

Using a pre-built toolchain.

python3 -m relenv toolchain download

Building a toolchain from scratch.

python3 -m relenv toolchain build

After installing the Relenv toolchain for the architecture you are targeting you build a Relenv Python build.

python3 -m relenv build --clean

Mac OS Dependencies

• developer tools

Building on Mac OS

Run python3 -m relenv build --clean

How it Works

1. Build python from source.

2. Modify the rpath of all binaries so that shared libraries are loaded via relative paths.

3. Modify the shebangs of Python's scripts run Python using a relative path.

4. Install a small wrapper around Pip which makes sure the shebangs of installed scripst use the relative python. This wrapper will also limit the PYTHONPATH of scripts run to directories in our python environment.

Using The Build

After a build completes succesfully you'll have a self contained python. It should work just like any other python installation. The difference is this python can be moved around on the filesystem or even to other machines.

python3 relenv create myproject
./myproject/bin/pip3 install myproject
zip myproject.zip myproject

The newly created myproject relenv environment can be sent to freind, co-worker, or customer.

Pre-Built Relenv Builds

Because Relenv's builds are re-producable, a build on OS version should end up being exactly the same as one built on another OS or version. Therefore the builds created by the CI/CD pipelines in this repository can be used in lue of building yourself.