A simple and fast logging monad

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MIT licensed by winterland1989, zmactep
Maintained by

This package is a fork of great `monad-log`, as the original author is unreachable.

It provides a mtl style MonadLog class and a concrete monad transformer LogT, the main difference between this package and monad-logger are:

  • Base monad has to be an instance of MonadIO.

  • Parametrized logging environment for extensibility.

  • Basic logging environment type(Label,Loc,NameSpace,ThreadId) are included, and you can easily make your own.

  • JSON logging built-in.

  • default to fast-logger backend, with good stdout and file support.

If you are an application author, you can use LogT transformer, it's just a specialized reader monad to inject `Logger env`.

If you are a library author, you should do following two things:

  • make your monad stack an instance of MonadLog, usually you can do this by embedding `Logger env` into your monad's reader part.

  • provide a default formatter, and API to run with customized formatter.