Overview

Hut is a header-only library for Erlang libraries and small applications to stay agnostic to the logging framework in use. Its purpose is to allow the developers of umbrella applications to use their logging framework of choice and ensure that dependency stick to that choice as well.

Origin

The idea for Hut came out of a discussion about exometer_core's logging facilities.

Usage

1. Include Hut as a dependency in your toolchain.
2. Include Hut in your .erl files via -include_lib(hut/include/hut.hrl)
3. Log with

• ?log(Level, Msg) to log the given message
• ?log(Level, Fmt, Args) to format the given message with the arguments using io_lib:format/2
• ?log(Level, Fmt, Args, Opts) to pass additional options to the logging backend in use

4. Compile and pass the appropriate macro to the compiler to enable a certain backend as described next.

Supported Logging Backends

• io:format/2 as the default
• no-op logging via -DHUT_NONE
• SASL error_logger via -DHUT_ERROR_LOGGER
• Lager via -DHUT_LAGER
• custom callback module via -DHUT_CUSTOM -DHUT_CUSTOM_CB mycbmod (the module must provide the function log(Level, Fmt, Args, Opts)

Examples

Refer to the respective Makefile in each example for details.

• examples/basic shows the use of all backends from an Erlang library
• examples/elixir shows the using a Hut-enabled Erlang library within an Elixir application