logging library for Python that tells you why things happen

 Most logging systems tell you what happened in your application,
 whereas eliot also tells you why it happened.
 .
 eliot is a Python logging system that outputs causal chains of actions:
 actions can spawn other actions, and eventually they either succeed or fail.
 The resulting logs tell you the story of what your software did: what
 happened, and what caused it.
 .
 Eliot works well within a single process, but can also be used across
 multiple processes to trace causality across a distributed system.
 .
 Eliot is only used to generate your logs; you will still need tools like
 Logstash and ElasticSearch to aggregate and store logs if you are using
 multiple processes.