package easy_logging_yojson

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Configuration loader for easy_logging with yojson backend


Dune Dependency






Provides deserialisation of logging configuration (loggers instantation and handlers parameters) from json, using ppx_deriving_yojson.

 Logging infrastructure inspired by the Python logging module.

The aim of this module is to provide a quick and easy to use logging infrastructure.

It has the following features :

  • one line logger creation
  • log messages printf style, or [string] or [string lazy_t]
  • tree logging architecture for light configuration
  • handlers associated to each logger will format, filter and treat the message independantly.
  • use the infrastructure with your own handlers with the [MakeLogging] functor.
  • use tags to add contextual information to log messages

Published: 07 Oct 2019


Logging module for OCaml.

Quick start :

open Easy_logging
logger = Logging.make_logger "my_logger" Debug [Cli Debug];;
logger#info "log_message";;

See documentation at


Version 0.4

  • printf style logging is now the default

  • simplifed configuration in case of multiple loggers (and closer to the python module) : the loggers form a tree (based on their name, dots indicating descendence)

    • log items are passed to the handlers of a logger’s ancestors (so that few handlers need initialisation) (possible to override)

    • loggers inherit the level of their ancestor if not set explicitely

  • an additional package easy_logging_yojson provides initialisation of loggers from the json format (with ppx_deriving_yojson), so that configuration can be fully done outside the code.

Version 0.5

  • Renamed the Default_handlers module to handlers

  • tag type in Handlers is now string (was unit)

  • added the possibility to add filters to handlers

  • added tag_generator feature to loggers, to automatically add tags to all messages passed to a logger

version 0.5.1
  • log_level type is direcly accessible from Easy_logging and Easy_logging_yojson modules

version 0.5.2
  • more file_handler options (timestamp, versioning)

Version 0.6

  • Added more options to file handlers (automatic timestamps and/or versioning of file names)

  • Added CliErr handler to output to stderr

  • modified handlers type so that fully custom handlers can be instantiated

  • cleaned module API

  • log items contains a timestamp

Version 0.6.2
  • Added RotatingFile handlers : log file rotation based on file size

Dependencies (5)

  1. easy_logging = version
  2. ppx_deriving_yojson
  3. ppx_deriving >= "4.0" & < "5.0"
  4. dune >= "1.8"
  5. ocaml >= "4.04.0"

Dev Dependencies


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