Node.js pino logger show caller filename and line number

pino_trace_caller.js

import path from 'path'
import pino from 'pino'

const STACKTRACE_OFFSET = 2
const LINE_OFFSET = 7
const { symbols : { asJsonSym} } = pino

function traceCaller (pinoInstance) {
  const get = (target, name) => name === asJsonSym ? asJson : target[name]

  function asJson (...args) {
    args[0] = args[0] || Object.create(null)
    args[0].caller = Error().stack.split('\n').filter(s => !s.includes('node_modules/pino') && !s.includes('node_modules\\pino'))[STACKTRACE_OFFSET].substr(LINE_OFFSET).replace(path.resolve(__dirname, '..'), '')
    return pinoInstance[asJsonSym].apply(this, args)
  }

  return new Proxy(pinoInstance, { get })
}

const logger = traceCaller(pino({
  level: 'debug',
  prettyPrint: {
    colorize: true,
  }
}))

I wrote a version for Node which provides more information: https://gist.github.com/Caellian/53c91f78f9f54146edc73b4200cd4775

I needed the whole trace and have it be structured. Only works for Node (didn't test in browsers).

But in general, pino allows mixins (now?), so it's better to use those than wrapping the logger:

pino({
  // rest
  mixin: (base, level, logger) => {
    return { /* additional data; added from each log statement */ };
  },
}),

This makes it much more convenient to add trace information.