Seq Logging for JavaScript

This library makes it easy to support Seq from Node.js logging libraries, including Pino via pino-seq, and Bunyan via bunyan-seq. It is not expected that applications will interact directly with this package.

Usage

A Logger is configured with serverUrl, and optionally apiKey as well as event and batch size limits. requestTimeout can be used to adjust timeout for stalled connections, default: 30s.

let process = require('process');
let seq = require('seq-logging');

let logger = new seq.Logger({ serverUrl: 'http://localhost:5341' });

logger.emit({
    timestamp: new Date(),
    level: 'Information',
    messageTemplate: 'Hello for the {n}th time, {user}!',
    properties: {
        user: process.env.USERNAME,
        n: 20
    }
});

logger.close();

Events are sent using the emit() method, that internally performs asynchronous batching based on payload size.

When the application exits, close() ensures all buffered events are written. This can be done at any time otherwise using the flush() method. Both of these methods return promises indicating completion.

When logging from a browser, and the application is being navigated away or closed, a pagehide or unload event listener has limited options and asynchronous methods will usually not succeed. In that case, the application can call flushToBeacon() to queue all remaining buffered events into navigator.sendBeacon(). There is a size limit imposed by browsers so this is a best-effort attempt.

Implementations

• bunyan-seq - collect events from the Buyan logging framework
• pino-seq - A stream to send Pino events to Seq
• winston-seq - A Seq transport for Winston