定制lager的输出
lager的输出可以定制，这里是我的定制方案。
在lager/ebin/lager.app里面的env字段里添加：
{env,[...
{log_root, "log"},
{handlers, [
{lager_console_backend, error},
{lager_file_backend, [{file, "error.log"}, {level, error},{formatter, lager_default_formatter}, {formatter_config, ["=ERROR REPORT==== ", date, " ", time, " ===\n", sev, "(", pid, ":", module, ":", line, ") ", message, "\n\n"]}, {size, 10485760}, {date, "$D0"}, {count, 5}]},
{lager_file_backend, [{file, "console.log"}, {level, info}]}
]},
...
]}.
输出的结果是这样子的：
=ERROR REPORT==== 2016-03-17 15:47:22.915 === E(<0.85.0>:log_module:36) I:1