Logging

Vura ships a structured logger from @celsian/vura-core. It writes JSON in production and colorized, human-readable lines in development, carries per-request IDs, and is configurable by environment variable or in code.

import { getLogger } from '@celsian/vura-core';

const log = getLogger();
log.info('server started', { port: 3000 });
log.error('payment failed', { orderId: 'o_42', code: 'CARD_DECLINED' });

Every log call takes a message and an optional data object. The data is merged into the structured entry — in JSON mode it becomes top-level fields; in pretty mode it's appended inline.

The logger runs on every target Vura builds for. It imports nothing, takes its request IDs from Web Crypto and writes to process.stdout where there is one and console.log where there is not, so getLogger() works the same in a hot route, a Lambda function and a Cloudflare Worker. On a Worker its output is what wrangler tail shows.

Levels

log.debug(msg, data?);
log.info(msg, data?);
log.warn(msg, data?);
log.error(msg, data?);

Levels are ordered debug < info < warn < error. The logger drops anything below its minimum level (default info, so debug is hidden until you lower it).

Configuration

Set the level and format with environment variables — no code change needed:

Or configure a logger in code with createLogger():

import { createLogger } from '@celsian/vura-core';

const log = createLogger({
  level: 'debug',
  format: 'json',
  write: (line) => process.stderr.write(line), // custom sink
});

LoggerConfig:

Request tracing

Attach a request ID to a group of related log lines with a child logger. Everything logged through it carries the same requestId:

const log = getLogger();
const requestId = log.generateRequestId(); // crypto.randomUUID()
const reqLog = log.child(requestId);

reqLog.info('handling request');   // { ..., requestId }
reqLog.error('validation failed'); // same requestId

For request start/end timing, requestStart / requestEnd bookend a request and log its duration and status:

const ctx = log.requestStart('GET', '/api/orders'); // logs "request start"
// ... handle the request ...
log.requestEnd(ctx, 200);                            // logs "request end" with durationMs

requestEnd picks the level from the status code: info for < 400, warn for 4xx, error for 5xx.

API