Winston 3 Bugsnag Transport

Bugsnag transport for the logger Winston (v3+).
Relies on the official client @bugsnag/js.

⚠ esModuleInterop is required in your tsconfig in order for this project to be imported.

Getting started

yarn add winston-3-bugsnag-transport
# or
npm install --save winston-3-bugsnag-transport

How to

Create a winston logger and pass a new instance of BugsnagTransport to it. The constructor accepts any property from the default configuration of Winston Transports and an additional property bugsnag taking a configuration for the bugsnag client (@bugsnag/js, as of v6.3+).

import winston from 'winston';
import { BugsnagTransport } from 'winston-3-bugsnag-transport';

const logger = winston.createLogger({
  level: 'info',
  format: winston.format.json(),
  transports: [new BugsnagTransport({ bugsnag: { apiKey: 'API_KEY' } })],
});

// use your logger 🎉

Details of implementation

Severity

Bugsnag has a "Severity" feature which allows tagging errors as either error, warning or info. Winston has "Logging levels".
A mapping is made between Severity "info", "warning", "error" and Logging levels "info", "warn", "error". This is not something customizable at the present time but PRs are most welcome if you need to.

Logging recommendations

Logging levels have an importance, chose them carefully. Most of the time:
- error should be used for critical situations requiring a manual intervention
- warn is for unsual circumstances (to be reported!) that the application can recover from
- info can report anything useful: events, state changes, etc
Put all the useful details about the context/state of your application in the metadata of your logs (easy debugging, filtering, etc)
Consider Structured logging for even more useful/powerful logs (see what Bugsnag can do)

There are multiple ways to notify an error (or an event) to Bugsnag

Embedding an Error in log metadata (recommended)

try {
  // ...
} catch (error) {
  logger.warn('Thumbnail creation failed: original picture will be used', {
    error, // report "error" as-is in the metadata
    feature: 'picture-thumbnail',
    path: filePath,
    size: fileSize,
  });
}

The parameter meta of winston is passed as the metaData of @bugsnag/js. This way, in the Bugsnag dashboard, every scalar values are available in the "Custom" tab of the report, and each object (or error) has its own tab.

But it is also possible to report an error directly:

try {
  // ...
} catch (error) {
  logger.warn(error);
}

The message and stack of the error will be notified to Bugsnag.

Or by passing the error as meta (discouraged!)