⚙️ FastEnv

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⚙️ FastEnv: Unintrusive, on-demand environment manager creating lightweight shims for projects, without shell hooks or auto-loading scripts.

✨ Features

• On-Demand Environment Management: Unlike traditional tools, fastenv doesn’t automatically hook into your shell or execute scripts on directory changes. This keeps your shell clean and responsive, activating environments only when explicitly needed.

• Manual Reloading for Flexibility: With fastenv, environment variables are loaded via fastenv reload, giving you full control over when changes take effect. Simply run this command whenever you update your .envrc, ensuring no unintended behavior or lag from automatic loading.

• Shim-Based Execution: Instead of modifying your shell environment directly, fastenv uses shims—small binaries that point to the required executables. This means commands within each project’s environment are executed seamlessly, without polluting your global environment.

• Seamless Compatibility with Existing .envrc Files: fastenv is fully compatible with existing .envrc files, making it easy to adopt without rewriting environment scripts. Drop in fastenv, and your environment configurations work as expected.

• Inspired by Volta’s Efficient Node.js Management: Borrowing ideas from Volta’s approach to Node.js version management, fastenv provides targeted control over environments while avoiding interference with your shell setup.

🚀 Installation

fastenv is work in progress. that said, I use it daily at work

Download the latest binary and:

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

# You can remove "direnv hook" from your bashrc/zshrc, but the tool needs to
# stay installed.

Some notes:

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

• fastenv also currently does not have pre-built binaries. You need to install Rust and install it using Rust's package manager, Cargo.

• fastenv assumes a POSIX environment.

Installation from source

cargo install fastenv  # latest stable release
cargo install --git https://github.com/trinhminhtriet/fastenv  # latest git SHA

💡 Usage

# Alternatively you can shim commands explicitly. Be careful: Any command you
# missed (such as 'python' or 'pip') would run outside of the virtualenv!
fastenv shim sentry pytest

# You can also run commands within the current .envrc without shimming them.
fastenv 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.
fastenv shim git

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

# Or alternatively, substitute your shell with one where your .envrc is loaded
exec fastenv exec $SHELL

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

# Or shim 'make', so your Makefile runs in the virtualenv.
fastenv shim make

# Curious which binary is actually being executed?
fastenv which make
# /home/user/.fastenv/bin/make

# Or for general debugging, increase the log level:
QUICKENV_LOG=debug make
# [DEBUG fastenv] argv[0] is "make"
# [DEBUG fastenv] attempting to launch shim
# [DEBUG fastenv] abspath of self is /home/user/.fastenv/bin/make
# [DEBUG fastenv] removing own entry from PATH: /home/user/.fastenv/bin
# [DEBUG fastenv] execvp /usr/bin/make
# ...
```

## 🗑️ Uninstallation

Running the below command will globally uninstall the `fastenv` binary.

```bash
cargo uninstall fastenv

Remove the project repo

rm -rf /path/to/git/clone/fastenv

🤝 How to contribute

We welcome contributions!

• Fork this repository;
• Create a branch with your feature: git checkout -b my-feature;
• Commit your changes: git commit -m "feat: my new feature";
• Push to your branch: git push origin my-feature.

Once your pull request has been merged, you can delete your branch.

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.