@kasa/koa-logging

A middleware that logs request and response in Koa

Installation

# Using NPM
$ npm install --save @kasa/koa-logging
# Using Yarn
$ yarn add @kasa/koa-logging

Dependencies

Koa 2.0+
Node.js 8.0.0+

Usage

Use koa-request-id as a middleware for a koa app. By default, it writes logs into stdin for HTTP requests, responses and errors. Every log include the request id, which logger will try to get from common places such as ctx.reqId, ctx.state.reqId, ctx.req.id.

In the following example, you can check the request and response logs from stdin:

// app.js
const Koa = require('koa');
const requestId = require('@kasa/koa-request-id');
const logging = require('@kasa/koa-logging');
const pino = require('pino');
const app = new Koa();
app.use(requestId());
app.use(logging({ logger: pino() }));
app.use(async ctx => {
  ctx.body = 'Hello, logging!';
});
app.listen(3000);

$ node app.js || pino-pretty -c -l -t

$ curl -X POST http://localhost:3000/users

INFO [2018-11-04 09:54:00.596 +0000] (app/15600 on my-macbook): POST /users (4f83e15b-c34c-4f8c-9f57-938e54e54ae3)
    reqId: "4f83e15b-c34c-4f8c-9f57-938e54e54ae3"
    req: {
      "method": "POST",
      "path": "/users",
      "url": "/users",
      "headers": {
        "host": "localhost:3000",
        "user-agent": "curl/7.54.0",
        "accept": "*/*"
      },
      "protocol": "http",
      "ip": "127.0.0.1",
      "query": {}
    }
    event: "request"

API

Creating an middleware

You can create a new logging middleware by passing the existing pino logger and the relevant options to logging;

const logger = pino();
const middleware = logging({
  logger,
  serializers: {},
  overrideSerializers: true,
  getReqId: (ctx) => ctx.reqId,
  getRequestLogLevel: (ctx) => 'info',
  getResponseLogLevel: (ctx) => ctx.state >= 500 ? 'error' : 'info',
  getErrorLogLevel: (err) => 'error'
});

Middleware Configuration

These are the available config options for the middleware. All is optional except logger.

{
  // Logger instance of pino
  logger: pino(),
  // Serializers to override defaults provided
  serializers: {
    req: (ctx) => ({
      ...
    }),
    user: (ctx) => ({
      ...
    })
  },
  // Ovveride serializers if true (default: true)
  overrideSerializers: true,
  // Function to get the request id from `ctx`
  getReqId: (ctx) => ctx.reqId,
  // Function to decide log level of the request from `ctx`
  getRequestLogLevel: (ctx) => 'info',
  // Function to decide log level of the response from `ctx`
  getResponseLogLevel: (ctx) => ctx.state >= 500 ? 'error' : 'info',
  // Function to decide log level of the error from `err`
  getErrorLogLevel: (err) => 'error'
}

Contributing

Bug Reports & Feature Requests

Please use the issue tracker to report any bugs or ask feature requests.