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. Eliot is released by ClusterHQ <https://docs.clusterhq.com>, the Data People for Docker™, and is available at https://pypi.python.org/pypi/eliot. Here's what your logs might look like before using Eliot: Going to validate http://example.com/index.html. 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"} - {"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"} What's New in 0.5.0: - Added support for Python 3.4. - Most public methods and functions now have underscore-based equivalents to the camel case versions, e.g. eliot.write_traceback and eliot.writeTraceback, for use in PEP 8 styled programs. Twisted-facing APIs and pyunit assertions do not provide these additional APIs, as camel-case is the native idiom. - eliot.to_file outputs log messages to a file. - Documented how to load Eliot logging into ElasticSearch via Logstash. - Documentation has been significantly reorganized.