bun-plugin-pino

Why?

Pino uses worker threads internally. Some dependencies and any transports need to be bundled separately or they won't get resolved at runtime and you'll get errors like error: unable to determine transport target for "...".

Your bundles work on the machine that built them but break in other environments like Docker? It's because Bun will resolve and and hardcode absolute paths from this particular environment into the bundle. Runtime resolution of these modules will fail elsewhere.

How?

This plugin bundles Pino's dependencies separately and fixes runtime imports in the main bundle.

Install

bun add -d bun-plugin-pino

Use the JS API to build

import { bunPluginPino } from 'bun-plugin-pino';

await Bun.build({
  entrypoints: ['./src/index.ts'],
  outdir: './dist',
  plugins: [
    bunPluginPino({
      transports: ['pino-loki'], // any additional transports you may be using
      // logging?: "default" | "plain" | "quiet"
    }),
  ], 
});

Output

./dist
├── index.js
├── thread-stream-worker.js
├── pino-file.js
└── pino-worker.js
└── [transport].js

Notes

If you have several libraries that don't play well with the bundler it's probably easier to mark them as external, resolve the versions at build time, add the packages with strict versions into a runtime package json, and finally bun install --production in CI to get a slim node_modules. This is the workaround I'm using with a monorepo because Bun doesn't support scoped installs at this time.