A built-in layout which formats log messages by an arbitrary user defined function.

Behaviours: Logi.Layout.

This layout formats log messages by format_fun/0 which was specified by the argument of new/1.

Note

This module is provided for debuging/testing purposes only.

A layout will be stored into a logi_channel’s ETS. Then it will be loaded every time a log message is issued. Therefore if the format function (format_fun/0) of the layout is a huge size anonymous function, all log issuers which use the channel will have to pay a non negligible cost to load it.

Examples

iex> layout0 = Logi.BuiltIn.Layout.Fun.new(fn (_, format, data) -> :io_lib.format("[LAYOUT_0] " <> format <> "\n", data) end)
iex> {:ok, _} = Logi.Channel.install_sink(Logi.BuiltIn.Sink.IoDevice.new(:foo, [layout: layout0]), :info)
iex> Logi.info "hello world"
#OUTPUT# [LAYOUT_0] hello world

iex> layout1 = Logi.BuiltIn.Layout.Fun.new(fn (_, format, data) -> :io_lib.format("[LAYOUT_1] " <> format <> "\n", data) end)
iex> {:ok, _} = Logi.Channel.install_sink(Logi.BuiltIn.Sink.IoDevice.new(:bar, [layout: layout1]), :info)
iex> Logi.info "hello world"
#OUTPUT# [LAYOUT_1] hello world
#OUTPUT# [LAYOUT_0] hello world