Set global environment variable out of Node.js

Question

I am trying to set a global environment variable out of my node.js app.

The goals are:

1. When restarting the APP, the environment variable should still be set
2. When opening a new shell, it should be usable
3. If possible: When rebooting, same as 1.
4. It should work on Linux, Mac OS X (and needs an alternate SET command for windows)

Here is what I did:

var setEnv = require('child_process')
        .spawn('export GLOBALVARNAME='+my.value,{
          stdio: 'inherit',
          env: process.env
        });

But this causes in

{ [Error: spawn export GLOBALVARNAME=foobar ENOENT]
  code: 'ENOENT',
  errno: 'ENOENT',
  syscall: 'spawn export GLOBALVARNAME=foobar',
  path: 'export GLOBALVARNAME=foobar',
  spawnargs: [] }

I didn't test this on Windows, but on Mac OS X (and Linux) the right command on bash is export GLOBALVARNAME=value. For Windows the right command should be SET GLOBALVARNAME=value - isn't it ?

So the main question is: Whats going wrong with the manual working export GLOBALVARNAME=foobar ?

Vasiliki

to understand why it is giving you ENOENT check out #19903328 – Stole

Answer 1

As other answers have pointed out, shelling out and changing an environment variable is basically a NO-OP. Either you want to change the environment for your current process and its children or you want to change it for new processes. Editing /etc/profile will make the change for any new processes as @Hmlth says.

If you want to change the environment for your current process this is straight forward:

process.env.YOUR_VAR = 'your_value';

Stole

Answer 2

export is not a standalone command but a shell builtin that sets the environment variable for the current shell process and its children forked after it is set.

You can't set an environment variable for processes that are not descendants of the current process. And under Linux, there is no such thing as system environment variable.

Under Linux, your variable should be set in the init script that spawns your app or in the systemd unit. If you want it to be available in interactive user shells, it should be set in /etc/profile or /etc/profile.d

.

Chino

I thought it is a standalone command ... that is bad. So I need to open a file and write into it. Damn... – Vasiliki

#4870828 shows how to access your environment without shelling out. It works for writes too. – Stole

Answer 3

Give this a try:

https://www.npmjs.com/package/shelljs

I don't think it is possible for a child process to change the parent's process environment. So I don't really think it is possible to use child_process.

Sample code:

var shell = require('shelljs');
shell.exec('export ENV_VARIABLE=ABRACADABRA');

Hines

you are right, it doesn't work using child_process. Thought export makes things global with the effect it is not relevant what is the parent shell... – Vasiliki

It wont work in windows also. The main aim for shelljs is mutiplatform – Ahl