[SOLVED] Set environment variables from file of key/value pairs in Nu

Set environment variables from file of key/value pairs in Nu

As in this question for Bash, I'd like to have a simple .env file or similar that I can read into the Nushell environment. While I'll typically use this for API keys, to simply re-use the same example from that question:

MINIENTREGA_FECHALIMITE="2011-03-31"
MINIENTREGA_FICHEROS="informe.txt programa.c"
MINIENTREGA_DESTINO="./destino/entrega-prac1"

Of course, Nushell is not POSIX, so none of those answers will work.

The Nushell syntax for setting an environment variable is:

$env.foo = "value"

And while it's possible to source-env a file that modifies the environment, that file needs to be a valid Nu script, which the .env is not.

I'd like to keep the structure of the file "standard" so that it can be used with other shells and tools, but how can I use it to set environment variables in Nushell?

Solution

Using parse you can achieve very nice results with only nushell commands.

This function allows opening a .env file with quotes and without. It also handles comments.

def "from env" []: string -> record {
  lines 
    | split column '#' 
    | get column1 
    | filter {($in | str length) > 0} 
    | parse "{key}={value}"
    | update value {str trim -c '"'}
    | transpose -r -d
}

Comment handling is done by splitting on # and getting the first element, then it remove any empty lines. After that it uses the parse mentioned earlier to parse the lines. Then it trims quotes if any exists. Finally using tranpose -r -d will transpoe the table into an object.

Then you can do something like open .env | load-env.

Edit: This is now also part of the nu_scripts repo, you can find it here.