dotenv

Usage: dotenv [--environment | -e path] [command] [args...]

Place a .env file at the same level where the current working directory is, then execute dotenv [command] [args...].

Additionally, use a .env file from ~/.dotenv/ or wherever $DOTENV_FOLDER_PATH points to, by specifying $DOTENV or --environment=filename or -e=filename (without the extension) and it will be used automatically. If the path passed is absolute, then whatever file passed will be used as environment if it can be parsed as a key=value format.

If the dotenv file sets an environment variable named DOTENV_COMMAND whose value is a valid, runnable command, the command will be used and all the remaining arguments will be sent to the command. For example, the following call will execute kubectl get pods

$ cat ~/.dotenv/kubectl.env
DOTENV_COMMAND=kubectl
KUBECONFIG=/home/patrick/.kube/cluster.yaml

$ dotenv -e=kubectl get pods
# since the command is already set in the dotenv file, you
# don't need to specify it like "dotenv -e=kubectl kubectl get pods"

If $DOTENV_STRICT is set to any value, and set either through environment variables or in the environment variables file, strict mode is applied, where the command gets executed only with the environment variables from the environment file, and without the environment variables from the environment. This mode is useful to not leak environment variables to your commmands that don't really need them, but also keep in mind some programs rely on $PATH to be set, or $HOME or other useful environment variables.

A cool example with no arguments but configuration given via environment variables:

$ DOTENV=<(echo -e "DOTENV_COMMAND=env\nNAME=joe\nDOTENV_STRICT=1") dotenv
NAME=joe

dotenv will execute your command, stdin, stdout and stderr will be piped, and the exit code will be passed to your terminal.

Installation

Download the binary from the Releases page and place the binary in a place in your $PATH. Then simply call dotenv with whatever configuration needed.

... but why?

dotenv comes as a solution to a problem I was running pretty often. I do a lot of terminal stuff and some CLIs use files to configure themselves while others use a combination of an environment variable that somehows configure the rest of the CLI via a file.

As an example, the openstack CLI uses OS_CLOUD to define a "cloud configuration" which is then taken from the file at ~/.config/openstack/clouds.yaml which can define multiple clouds. I'm always changing which cloud I use, and I realize openstack can also be configured with environment variables such as:

export OS_AUTH_URL=<url-to-openstack-identity>
export OS_PROJECT_NAME=<project-name>
export OS_USERNAME=<user-name>
export OS_PASSWORD=<password>  # (optional)

So rather than doing that, I created a few files in ~/.dotenv/ which point to a specific cloud configuration, say ~/.dotenv/cloud1.env, ~/.dotenv/cloud2.env. They all contain the same set of environment variables but with different values, plus, they contain a single DOTENV_COMMAND variable which is always set to openstack, like this:

DOTENV_COMMAND=openstack
OS_AUTH_URL=<url-to-openstack-identity>
OS_PROJECT_NAME=<project-name>
OS_USERNAME=<user-name>
OS_PASSWORD=<password>  # (optional)

Now, depending on what cloud I want to execute commands, like getting servers (openstack server list) or loadbalancers (openstack loadbalancer list), I simply do:

$ dotenv -e=cloud1 server list
$ dotenv -e=cloud2 loadbalancer list

Or I can even alias the commands to work a bit faster:

alias os1='dotenv -e=cloud1'
alias os2='dotenv -e=cloud2'

I realize though that, at the end, we come down to managing multiple files rather than just one (as in, we went from one clouds.yaml to 2 .env files), but the solution is highly scriptable and oftentimes the clouds.yaml file is being edited to support new clouds (I work with quite a few usernames, passwords and cloud endpoints).

Other more commonly used feature is that I store some .env file in the local directory where I'm developing a Go web server which needs to have environment variables that I can't post to Github, like $PORT or even $SMTP_USERNAME. This is the easiest to solve with dotenv because of this:

$ cat .env
PORT=8081
SMTP_HOST=localhost
SMTP_USER=patrick
SMTP_PASS=demo

$ dotenv go run *.go
Server listening on port 8081...

Adding new features?

I welcome any Pull Request. The license of this software is also permissive enough that you can make it yours and / or use it in corporate environments. The sky is the limit!

Most of the code here has been written in a rush, so assume typos are a thing. You can also see there's a lack of testing, so if you're into that, send me a PR! No PR is useless when it comes down to this app.