compose: undefined in logger

there is a "undefined" when I run the compose/app.js
undefined / - 6
undefined / - 1
undefined /aaaa - 0

I think that the code 'this' will be modified to 'ctx' in the 'logger()' function.

Start with compose/app.js and inspect the logger() function, focusing on the reported use of `this` versus `ctx`. Run the app to reproduce the `undefined` log entries; done means the logger output no longer begins with `undefined` for the shown requests.

Written by the indexing model from the issue text.