Eliot provides a structured logging and tracing system for Python that generates log messages describing a forest of nested actions. Actions start and eventually finish, successfully or not. Log messages thus tell a story: what happened and what caused it. Here's what your logs might look like before using Eliot: Going to validate http://example.com/index.html [1]. Started download attempted. Download succeeded! Missing <title> element in "/html/body". Bad HTML entity in "/html/body/p[2]". 2 validation errors found! After switching to Eliot you'll get a tree of messages with both message contents and causal relationships encoded in a structured format: * {"action_type": "validate_page", "action_status": "started", "url": "http://example.com/index.html" [1]} * {"action_type": "download", "action_status": "started"} * {"action_type": "download", "action_status": "succeeded"} * {"action_type": "validate_html", "action_status": "started"} * {"message_type": "validation_error", "error_type": "missing_title", "xpath": "/html/head"} * {"message_type": "validation_error", "error_type": "bad_entity", "xpath": "/html/body/p[2]"} * {"action_type": "validate_html", "action_status": "failed", "exception": "validator.ValidationFailed"} * {"action_type": "validate_page", "action_status": "failed", "exception": "validator.ValidationFailed"} Features: * Structured, typed log messages. * Ability to log actions, not just point-in-time information: log messages become a trace of program execution. * Excellent support for unit testing your logging code. * Emphasis on performance, including no blocking I/O in logging code path. * Optional Twisted support. * Designed for JSON output, usable by Logstash/Elasticsearch. * Supports CPython 2.7, 3.3 and PyPy. Eliot is released by HybridCluster [2] under the Apache 2.0 License. To install: $ pip install eliot Downloads are available on PyPI [3]. Documentation can be found on Read The Docs [4]. Bugs and feature requests should be filed at the project Github page [5]. Links: ------ [1] http://example.com/index.html [2] https://hybridcluster.github.io [3] https://pypi.python.org/pypi/eliot [4] https://eliot.readthedocs.org/ [5] https://github.com/hybridcluster/eliot