Chopmunk
Chopmunk is a minimalist logging approach. The idea is to use coroutines as adivsed in Dave Beazley's tutorial:
http://www.dabeaz.com/coroutines/
Evaluating JSON logs with underscore-cli
Since a json file sink preceded by a jsonifier sink leads to one JSON document per line, it cannot be processed with tools like underscore-cli directly. This bash command helps:
cat <yourlog> | while read line; do echo $line | underscore pretty; done
This will pretty print each document after the other.