Overview

Module logi_builtin_layout_fun

• Description
• Data Types
• Function Index
• Function Details

Copyright © 2014-2016 Takeru Ohta <phjgt308@gmail.com>

Behaviours: logi_layout.

Description

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

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.

EXAMPLE

  > error_logger:tty(false). % Suppresses annoying warning outputs for brevity
 
  > Context = logi_context:new(sample_log, info).
  > FormatFun = fun (_, Format, Data) -> io_lib:format("EXAMPLE: " ++ Format, Data) end.
  > Layout = logi_builtin_layout_fun:new(FormatFun).
  > lists:flatten(logi_layout:format(Context, "Hello ~s", ["World"], Layout)).
  "EXAMPLE: Hello World"
  

  > Layout0 = logi_builtin_layout_fun:new(fun (_, Format, Data) -> io_lib:format("[LAYOUT_0] " ++ Format ++ "\n", Data) end).
  > {ok, _} = logi_channel:install_sink(logi_builtin_sink_io_device:new(foo, [{layout, Layout0}]), info).
  > logi:info("hello world").
  [LAYOUT_0] hello world
 
  > Layout1 = logi_builtin_layout_fun:new(fun (_, Format, Data) -> io_lib:format("[LAYOUT_1] " ++ Format ++ "\n", Data) end).
  > {ok, _} = logi_channel:install_sink(logi_builtin_sink_io_device:new(bar, [{layout, Layout1}]), info).
  > logi:info("hello world").
  [LAYOUT_0] hello world
  [LAYOUT_1] hello world
  

Data Types

format_fun()

format_fun() = fun((logi_context:context(), io:format(), logi_layout:data()) -> logi_layout:formatted_data())

A log message formatting function

Function Index

Function Details

new/1

Creates a layout which formats log messages by FormatFun

Overview

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