# `quickenv`: An unintrusive environment manager
[`direnv`](https://direnv.net/) 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](https://docs.python.org/3/tutorial/venv.html), 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 `.envrc`s that people end up writing
sometimes are. `direnv` does not have a reliable, out-of-the-box way to cache
the execution of `.envrc`s, 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 `.envrc`s, 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
it creates shim binaries that dispatch to the right executable.
`quickenv` is heavily inspired by [volta](https://volta.sh/) which achieves
version management for nodejs by also providing "shim" binaries for the most
common commands (`yarn`, `npm`, `node`).
## Installation
Install quickenv:
* [from GitHub](https://github.com/untitaker/quickenv/releases) as a standalone binary
* [from AUR for ArchLinux](https://aur.archlinux.org/packages/quickenv), e.g. `paru -S quickenv`
* [or build from source](#ref-build-from-source)
Then set it up in your shell:
```bash
# 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
# You can remove "direnv hook" from your bashrc/zshrc, but the tool needs to
# stay installed.
```
Some notes:
* `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](https://rustup.rs/) and install it using Rust's package
manager, Cargo.
* `quickenv` assumes a POSIX environment.
<a name=ref-build-from-source></a>
### Building from source
```bash
cargo install quickenv # latest stable release
cargo install --git https://github.com/untitaker/quickenv # latest git SHA
```
## Usage
We're going to check out [sentry](https://github.com/getsentry/sentry), because
that's one of the `.envrc`s I use. Note that Sentry's `.envrc` only works on
MacOS.
```bash
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
# As part of executing the .envrc, a virtualenv has been created at './.venv/'.
# There are multiple commands available in '.venv/bin/', such as 'pytest' (a test
# runner), or 'sentry' (the main application).
# 'quickenv shim' makes those commands available in your shell.
quickenv shim
# These commands will now run with the virtualenv enabled.
sentry devserver --workers
pytest tests/sentry/
```
## Advanced usage
```bash
# Alternatively you can shim commands explicitly. Be careful: Any command you
# missed (such as 'python' or 'pip') would run outside of the virtualenv!
quickenv shim sentry pytest
# You can also run commands within the current .envrc without shimming them.
quickenv exec -- pytest
# Your git hooks don't execute in the virtualenv for some reason? Just replace
# 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.
set -o allexport
eval "$(quickenv vars)"
set +o allexport
# Or alternatively, substitute your shell with one where your .envrc is loaded
exec quickenv exec $SHELL
# Or shim 'bash', so that when you open a subshell, the virtualenv is activated.
quickenv shim bash
# Or shim 'make', so your Makefile runs in the virtualenv.
quickenv shim make
# Curious which binary is actually being executed?
which make
# --> /home/user/.quickenv/bin/make
quickenv which make
# --> /usr/bin/make
quickenv exec which make
# --> /usr/bin/make
# Or for general debugging, increase the log level:
QUICKENV_LOG=debug make
# [DEBUG quickenv] argv[0] is "make"
# [DEBUG quickenv] attempting to launch shim
# [DEBUG quickenv] abspath of self is /home/user/.quickenv/bin/make
# [DEBUG quickenv] removing own entry from PATH: /home/user/.quickenv/bin
# [DEBUG quickenv] execvp /usr/bin/make
# ...
```
## Command Reference
```
An unintrusive environment manager
Usage: quickenv <COMMAND>
Commands:
reload Execute .envrc in the current or parent directory, and cache the new variables
vars Dump out cached environment variables
shim Create a new shim binary in ~/.quickenv/bin/
unshim Remove a shim binary from ~/.quickenv/bin/
exec Run a program with .envrc loaded without having to shim it
which Determine which program quickenv's shim would launch under the hood
help Print this message or the help of the given subcommand(s)
Options:
-h, --help Print help
-V, --version Print version
Environment variables:
QUICKENV_LOG=debug to enable debug output (in shim commands as well)
QUICKENV_LOG=error to silence everything but errors
QUICKENV_NO_SHIM=1 to disable loading of .envrc, and effectively disable shims
QUICKENV_SHIM_EXEC=1 to directly exec() shims instead of spawning them as subprocess. This can help with attaching debuggers.
QUICKENV_NO_SHIM_WARNINGS=1 to disable nags about running 'quickenv shim' everytime a new binary is added
QUICKENV_PRELUDE can be overridden to customize the shell code injected before executing each envrc. By default, quickenv loads ~/.config/direnv/lib/*.sh files and then runs 'eval "$(direnv stdlib)"' to mimic direnv's behavior.
```
## License
Licensed under `MIT`, see `LICENSE`.