Output Common Log Format access logs to any stream. Defaults to process.stdout.

npm install koa-accesslog

var koa = require('koa');
var accesslog = require('koa-accesslog');
var app = koa();

app.use(accesslog());

127.0.0.1 - - [19/Nov/2014:13:47:37 +0100] "GET / HTTP/1.X" 404 -

You may configure Accesslog to use any writable stream such as an instance of stream.PassThrough as seen below.

var log = new stream.PassThrough();
app.use(accesslog(log));

MIT