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How to Manage Environment Variables with direnv

Tadashi Shigeoka ·  Thu, April 4, 2019

I’ll introduce how to manage environment variables with direnv.

direnv

Prerequisites

Similar Libraries *dotenv

There are dotenv-style libraries as similar libraries to direnv.

Benefits of direnv

*dotenv requires explicitly calling Dotenv.load from source code to load environment variables.

direnv’s benefit is that you don’t need to explicitly write Dotenv.load in source code, and it automatically activates when you move to a directory.

Another benefit is that you don’t need to use different *dotenv libraries depending on programming languages like Node.js or Ruby. By the way, direnv is written in Go.

Installing direnv

macOS Edition

On macOS, installing with Homebrew is easy.

brew install direnv

Add Hook to Shell

Refer to Setup to add a hook to your shell.

For zsh

Since I use zsh, I’ll introduce the zsh case.

Just add the following code to your ~/.zshrc file.

eval "$(direnv hook zsh)"

Don’t forget to run source ~/.zshrc or reopen Terminal after adding the above.

Using direnv with New .envrc

direnv edit .

direnv edit .

Write the environment variables you want to load in the .envrc file using export as follows.

# .envrc
export AWS_DEFAULT_REGION=ap-northeast-1
export AWS_ACCESS_KEY_ID=YOUR_ACCESS_KEY_ID
export AWS_SECRET_ACCESS_KEY=YOUR_SECRET_ACCESS_KEY

direnv: loading

$ cd /path/to/envrc/dir
direnv: loading .envrc
direnv: export +AWS_ACCESS_KEY_ID +AWS_DEFAULT_REGION +AWS_SECRET_ACCESS_KEY

Using direnv with Existing .envrc

Run direnv allow if Error Occurs

If you see the error message direnv: error .envrc is blocked. Run direnv allow to approve its content., run direnv allow as indicated in the error message.

Other direnv Tips

direnv: unloading

When you move away from a directory with direnv configured, environment variables are automatically unloaded.

$ cd ../
direnv: unloading

That’s all from the Gemba on wanting to manage environment variables with direnv.