Winston 3 Transport for Journald

Documentation

Why?

Winston has structured logging with non-structured messages as well. It's become the ubiquitous solution in the logging space (alongside bunyan, and others). Structured logs are nice.

Journald solves a number of problems around logs. It solves the problem of compression, rotation, and storage on behalf of the application. Its format, and approach is congruent with Winston, in that it supports structured logging as a "first class" primitive.

The intent of this Winston 3 transport is to be a lightweight wrapper journald. This, being a native Winston 3 transport has some benefits over winston-journald, a Winston 2 transport, like dynamic log levels.

Also this can compile, and be installed on Mac OS.

Installation

Yarn

yarn add winston-journald3

npm

yarn add winston-journald3

Options

interface Options extends TransportStream.TransportStreamOptions {
    /* systemd syslog identifier */
    identifier?: string;
    /* Use finalizing formatter message as message sent to systemd */
    messageAsFinalizingFormat?: boolean;
}

Examples

Typescript

Basic usage example:

import journald3 from 'winston-journald3'

const journald = new journald3({ 'identifier': 'winstontest' })
const logger = winston.createLogger({
        level: 'info',
        format: winston.format.simple(),
        defaultMeta: { service: 'user-service' },
        transports: [
            journald
        ]
    })

// Send a basic message
logger.info("testmessage")

// Send a message with metadata
logger.info("fieldsmessage", { "testkey": "value" })

Example output:

{
  "_SYSTEMD_SESSION": "91",
  "_SOURCE_REALTIME_TIMESTAMP": "1606696055349487",
  "_GID": "1000",
  "_SYSTEMD_UNIT": "session-91.scope",
  "_TRANSPORT": "journal",
  "_SYSTEMD_OWNER_UID": "1000",
  "__CURSOR": "s=ee01b1e58fa04593b54f5c945114c4f5;i=1c64;b=204ba6d0b1bb40099b2ad31e83f351c5;m=158f35af90;t=5b54813a42167;x=b982ccf17f5ffbf7",
  "_SYSTEMD_SLICE": "user-1000.slice",
  "_PID": "593497",
  "_SYSTEMD_USER_SLICE": "-.slice",
  "_SYSTEMD_CGROUP": "/user.slice/user-1000.slice/session-91.scope",
  "TESTKEY": "value",
  "_SYSTEMD_INVOCATION_ID": "b7bb79f954304fc1bd570ed559e07901",
  "_CMDLINE": "/home/sargun/.nvm/versions/node/v12.20.0/bin/node /home/sargun/winston-journald3/node_modules/.bin/jest ./test --forceExit --coverage",
  "LEVEL": "info",
  "_EXE": "/home/sargun/.nvm/versions/node/v12.20.0/bin/node",
  "_UID": "1000",
  "_AUDIT_LOGINUID": "1000",
  "_COMM": "node",
  "_BOOT_ID": "204ba6d0b1bb40099b2ad31e83f351c5",
  "MESSAGE": "fieldsmessage",
  "_AUDIT_SESSION": "91",
  "__REALTIME_TIMESTAMP": "1606696055349607",
  "__MONOTONIC_TIMESTAMP": "92596973456",
  "PRIORITY": "6",
  "SERVICE": "user-service",
  "SYSLOG_IDENTIFIER": "winstontest",
  "_CAP_EFFECTIVE": "0",
  "_HOSTNAME": "ubuntu",
  "_SELINUX_CONTEXT": "unconfined\n",
  "_MACHINE_ID": "ad10428b70b952a9fe1a4386587e93fe"
}

Vanilla Javascript

// TODO: Can someone please fill this in?

Caveats

Logs statements greater than 1 MB may not work.