Minimal wrapper to log to journald

Documentation

Installation

Yarn

yarn add sd-journald

npm

npm i sd-journald --save

Interface:

import { Map as ImmutableMap } from 'immutable';
declare enum SyslogPrority {
    EMERG = 0,
    ALERT = 1,
    CRIT = 2,
    ERR = 3,
    ERROR = 3,
    WARNING = 4,
    WARN = 4,
    NOTICE = 5,
    INFO = 6,
    DEBUG = 7
}
declare class Journald {
    syslog_identifier: string;
    socket: Socket | null;
    constructor(syslog_identifier?: string);
    /**
     * This sends a mesage to journald. A syslog priority is required.
     */
    send(priority: SyslogPrority, message: string, kv: ImmutableMap<string, string> | null): void;
}
default journald = new Journald();
declare function send(priority: SyslogPrority, message: string, kv: ImmutableMap<string, string> | null): void;

The default export is an instance of journald. The syslog identifier by default is set to process.argv0, and it can be changed. There are several strict assertions that prevent the user from sending bad data to journald. You must the total size of the message is under 1MB. You must ensure that the keys start with A-Z, and only contain the letters underscore, A-Z, and 0-9. It will be automatically upcased.

Logging is performed synchronously due to a limitation with the underlying library unix-dgram.

Examples

Typescript

Basic usage example:

import journald, { SyslogPrority } from 'sd-journald'

/* Sending an unstructured message */
journald.send(SyslogPrority.INFO, "Test message")

Sending structured message:

import journald, { SyslogPrority } from 'sd-journald'
import { Map as ImmutableMap } from 'immutable'

journald.send(SyslogPrority.INFO, "Test message", new ImmutableMap({"key": "value"}))

Vanilla Javascript

// TODO: Can someone please fill this in?

Why?

This module has been written after because the alternative model has a dependency on libsystemd for compilaton. This means that you cannot build it on Mac OS. Although journald is not available on Mac OS, the idea is that this is a minimal library, and in the future may support remote destinations like systemd-journald-remote. It is meant to provide as low level as possible of an interface to systemd-journald writing without losing many features.