Determine if the current process is connected via stdout or stderr to the systemd journal.

NOTE ABOUT UBUNTU 16.04

This module checks the environment variable JOURNAL_STREAM which was introduced in systemd v231. As of this writing, Ubuntu 16.04 is using systemd v229, which means that this module will always return false in Ubuntu 16.04.

It is suggested that, in Ubuntu 16.04 and other systems with systemd < 231, set an environment variable for your process and use that to determine whether to log to systemd's journal or to stdout.

if (isConnected.sync() || process.env.VARIABLE_I_SET_TO_TRIGGER_JOURNAL) {
  // Log to the journal
}

Installation

npm install --save is-connected-to-systemd-journal

Usage (synchronous)

const isConnected = require('is-connected-to-systemd-journal')

let log = null;
if (isConnected.sync()) {
  // set up logging to require('systemd-journald') or other
}
else {
  // set up logging to some other sink (like console.out)
}

isConnected.stdoutSync() // is stdout connected to the journal
isConnected.stderrSync() // is stdout connected to the journal
isConnected.sync() // same as isConnected.stdoutSync

Usage (async)

const isConnected = require('is-connected-to-systemd-journal')

isConnected((err, connected) => {
  let log = null;
  if (connected) {
    // set up logging to require('systemd-journald') or other
  }
  else {
    // set up logging to some other sink (like console.out)
  }
})

isConnected.stdout(cb) // is stdout connected to the journal
isConnected.stderr(cb) // is stdout connected to the journal
isConnected(cb) // same as isConnected.stdoutSync