quickenv: An unintrusive environment manager

direnv is a manager for loading/unloading environment variables per-project. It achieves this by hooking into your shell and executing a shellscript called .envrc upon cd, loading environment variables generated by that shellscript into your current shell. It is useful for automatically activating virtualenvs, for example.

Unfortunately direnv can be a little bit "intrusive" to use. For a start, it runs its own code in your shell. This alone is not noticeable in terms of terminal responsiveness, but the various .envrcs that people end up writing sometimes are. direnv does not have a reliable, out-of-the-box way to cache the execution of .envrcs, as it is arbitrary code, and so it runs everytime you cd in and out of a project.

quickenv is a replacement for direnv. It works with existing .envrcs, and as such is a drop-in replacement, but how you interact with quickenv and how it loads environment variables is fundamentally different.

• quickenv does not hook into your shell. It only requires an addition to your PATH.
• quickenv does not load .envrc when changing directories. Instead you need to initialize quickenv per-project using quickenv reload, and rerun that command everytime the .envrc changes.
• quickenv does not even load environment variables into your shell. Instead you tell quickenv which binaries should run with those environment variables present (for example quickenv shim python pytest poetry), and quickenv will wrap those commands in a custom binary, and put that "shim" on your PATH.

quickenv is heavily inspired by volta which achieves version management for nodejs by also providing "shim" binaries for the most common commands (yarn, npm, node).

Installation

quickenv is work in progress and most likely contains bugs. that said, I use it daily at work

• quickenv currently assumes direnv is in your path, in order to load its "standard library".

• quickenv also currently does not have pre-built binaries. You need to install Rust, check out this repository, and install it yourself.

• quickenv assumes a POSIX environment.

# Install quickenv. Quickenv assumes itself to be installed in
# '~/.quickenv/bin/'. You can change that using QUICKENV_HOME.
cargo install quickenv
mkdir -p ~/.quickenv/bin/
mv ~/.cargo/bin/quickenv ~/.quickenv/bin/

# Into your bashrc/zshrc. This should be at the front of your PATH, such that
# quickenv can shim/shadow binaries effectively.
export PATH=$HOME/.quickenv/bin/:$PATH

Usage

We're going to check out sentry, because that's one of the .envrcs I use. Note that Sentry's .envrc only works on MacOS.

git clone https://github.com/getsentry/sentry
cd sentry

# Execute the .envrc and cache the resulting environment variables in ~/.quickenv/envs/.
# Sentry will prompt you to create a virtualenv, install dependencies via homebrew, etc.
# Re-run this command manually everytime the .envrc changes.
quickenv reload

# Tell quickenv to place "shim" binaries for those commands in ~/.quickenv/bin/
quickenv shim sentry pytest

# These commands will now run with the virtualenv enabled
sentry devserver --workers
pytest tests/sentry/

# Other commands not explicitly shimmed will end up not running in the
# virtualenv at all. Whoops!
python
pip install ...

# Better shim them!
quickenv shim python pip

Advanced usage

# Your git hooks don't execute in the virtualenv for some reason? Just replace/shadow
# git with a binary that itself loads the virtualenv.
quickenv shim git

# Actually activate the virtualenv in your current shell. `quickenv vars`
# prints all the extra environment variables with which each shimmed binary runs.
eval "$(quickenv vars)"

# Or shim 'bash', so that when you open a subshell, the virtualenv is activated.
quickenv shim bash

# Or shim 'make', so your Makefile runs in the virtualenv. This can save you from
# explicitly enumerating a bunch of commands, if you only ever run them via 'make'.
quickenv shim make

License

Licensed under MIT, see LICENSE.