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/*!
Using `env_logger` to drive a custom logger.
Before running this example, try setting the `MY_LOG_LEVEL` environment variable to `info`:
```no_run,shell
$ export MY_LOG_LEVEL='info'
```
If you only want to change the way logs are formatted, look at the `custom_format` example.
*/
#[macro_use]
extern crate log;
use env_logger::filter::{Builder, Filter};
use log::{Log, Metadata, Record, SetLoggerError};
const FILTER_ENV: &str = "MY_LOG_LEVEL";
struct MyLogger {
inner: Filter,
}
impl MyLogger {
fn new() -> MyLogger {
let mut builder = Builder::from_env(FILTER_ENV);
MyLogger {
inner: builder.build(),
}
}
fn init() -> Result<(), SetLoggerError> {
let logger = Self::new();
log::set_max_level(logger.inner.filter());
log::set_boxed_logger(Box::new(logger))
}
}
impl Log for MyLogger {
fn enabled(&self, metadata: &Metadata) -> bool {
self.inner.enabled(metadata)
}
fn log(&self, record: &Record) {
// Check if the record is matched by the logger before logging
if self.inner.matches(record) {
println!("{} - {}", record.level(), record.args());
}
}
fn flush(&self) {}
}
fn main() {
MyLogger::init().unwrap();
info!("a log from `MyLogger`");
}
|
