Modules to use log4rs easily.
```rust fn main() {
// 1. setting to rotate log files by size.
let setting = rotate::size::SettingBuilder::new()
.file_path("sample/sample.log")
.file_pattern("backup/sample.{}.log")
.build();
// 2. create log4rs Config.
let config = setting.configure().unwrap();
// 3. call init_config() as usual.
log4rs::init_config(config).unwrap();
let greeting = "hello, world!";
debug!("debug: {}", greeting);
info!("info: {}", greeting);
warn!("warn: {}", greeting);
error!("error: {}", greeting);
} ```
output:
``` $ tail -f sample/sample.log
2019-08-10T16:59:36.011987+09:00 [DEBUG] sampleapp debug: hello, world! 2019-08-10T16:59:36.012626+09:00 [INFO] sampleapp info: hello, world! 2019-08-10T16:59:36.012680+09:00 [WARN] sampleapp warn: hello, world! 2019-08-10T16:59:36.012731+09:00 [ERROR] sampleapp error: hello, world! ```