Request Logging

A single router.on() subscription turns every finished request into a structured access log, with no logging code inside handlers.

Basic Access Log

Listen for request:completed and print one line per request:

import { Router } from '@neabyte/deserve'

const router = new Router({
  routes: { directory: './routes' }
})

// One log line per finished request
router.on((event) => {
  if (event.kind === 'request:completed') {
    const { method, url, statusCode, durationMs } = event.metadata as {
      method: string
      url: string
      statusCode: number
      durationMs: number
    }
    console.log(`${method} ${url} ${statusCode} ${Math.round(durationMs)}ms`)
  }
})

await router.serve(8000)

Structured JSON Logs

Emit JSON when a log pipeline expects structured records:

router.on((event) => {
  if (event.kind === 'request:completed') {
    // Forward the full metadata as JSON
    console.log(JSON.stringify({
      at: event.timestamp,
      ...event.metadata
    }))
  }
})

The metadata already includes OpenTelemetry-aligned fields like route, serverAddress, userAgent, and requestSize. See the Event Reference for the full list.

Logging Slow Requests

Filter by duration to surface only slow traffic:

router.on((event) => {
  // Flag requests slower than 500ms
  if (event.kind === 'request:completed') {
    const { url, durationMs } = event.metadata as { url: string; durationMs: number }
    if (durationMs > 500) {
      console.warn(`SLOW ${url} ${Math.round(durationMs)}ms`)
    }
  }
})

For failures, see Error Reporting.