Logging / Module Caching

[atomdmac]

I'm attempting to use pino to log things from the server-side. Normally, I'd have a module set up like this:

import { pino } from "pino";

console.log('Starting Logger...');

export default pino({
  level: LOG_LEVEL,
  transport: {
    targets: [
      {
        level: LOG_LEVEL,
        target: "pino/file",
        options: {
          destination: `${LOG_DIRECTORY}/my-app.log`,
          append: true,
        },
      },
    ],
  },
});

While this does work, I've noticed that I see Starting Logger on every call to logger.debug(). It seems that the module is not cached and is spawning a new logger instance every time my code runs.

Can someone help me understand what's going on here? Is module caching disabled in Remix? Is there a better way to handle logging?

Thanks in advance!

[kiliman]

In development, Remix App Server purges the require cache on every request. This is mainly to support <LiveReload/>.

You'll want to store your pino object on the global object to survive the purge.

import pino from "pino";

declare global {
  var logger: pino.Logger;
}

const LOG_LEVEL = process.env.LOG_LEVEL || "info";
const LOG_DIRECTORY = process.env.LOG_DIRECTORY || "./logs";

function getLogger() {
  console.log("Starting Logger...");

  return pino({
    level: LOG_LEVEL,
    transport: {
      targets: [
        {
          level: LOG_LEVEL,
          target: "pino/file",
          options: {
            destination: `${LOG_DIRECTORY}/my-app.log`,
            append: true,
          },
        },
      ],
    },
  });
}

const logger: pino.Logger =
  process.env.NODE_ENV === "development"
    ? global.logger ?? (global.logger = getLogger())
    : getLogger();

export default logger;

[atomdmac]

@kiliman Thanks for the explanation! Won't this just export the locally defined logger instead of global.logger?

[kiliman]

Ok, I edited my example.