pino VS debug

Learn more about logging in Fastify and how to customize the Pino logger.

The Fastify framework includes the Pino logger by default (a really great logger with lots of cool features that doesn't compromise on performance). The framework itself allows a lot of really cool stuff, like controlling the level of logs at runtime.

Fastify provides a built-in logging mechanism based on Pino that allows you to capture various events in your applications. Once enabled, Fastify logs all incoming requests to the server and errors that occur while processing said requests. It also provides a convenient way to log custom messages through the log() method on the Fastify instance or the request object.

1. pino

Vitest is for frontend. Jest is not good for backend (I don’t like it for frontend either), take a look at this issue.

Have a look at https://github.com/pinojs/pino

NodeJS -> Pino, Winston, Bunyan, Npmlog, e.t.c.

Use a configurable logger like pino

Using pino as a logger, for every request on the _server_ , a unique ID generated client side in the headers, so a log may be something like:

Number of dependencies: one way to tell if a library is not too challenging to be used as study source is based on the production dependencies count. The fewer the better. For example, I chose debug because it only has 1 dependency (ms), while the rest of the code relies on core NodeJS modules - which is exactly what I was looking for - to learn how to build a library from scratch, not off the shelf libraries with many external deps, which in turn are based on more deps. There you go, dependency hell.

Another way to solve this is to have the logs in place, but only enable them conditionally. If you enable all the logs are the time, you only get a lot of noise that won't help you. If you are using JavaScript, you can use the package debug to add logs that are active by the DEBUG environment variable.

I'm using the debug package: https://www.npmjs.com/package/debug, but some reason I don't see millisecond diffs, which would be really useful.

Although it's used by Express, it's indeed more broadly, the way a popular NPM package called debug works, which is used internally in Express too. Under the hood, the debug package expects the DEBUG environment variable to determine what debug messages to print (could be on the console, or into a file, or into stdout to be collected by a log aggregator service).

Finally, if they're logs you want to be able to inspect in production without printing them to the console by default, you can use debug.

It is a drop-in, TypeScript replacement to enhance the widely popular https://www.npmjs.com/package/debug (230k weekly downloads).

debug - npm - Required. A popular library to write debug logs.

I strongly recommend using the debug package from NPM to organize your log messages

Use the [debug npm library](https://www.npmjs.com/package/debug) to disable your logging unless someone provides the right environment variable (e.g. DEBUG=* which enables all logging)