custom_format/
custom_format.rs

1/*!
2Changing the default logging format.
3
4Before running this example, try setting the `MY_LOG_LEVEL` environment variable to `info`:
5
6```no_run,shell
7$ export MY_LOG_LEVEL='info'
8```
9
10Also try setting the `MY_LOG_STYLE` environment variable to `never` to disable colors
11or `auto` to enable them:
12
13```no_run,shell
14$ export MY_LOG_STYLE=never
15```
16
17If you want to control the logging output completely, see the `custom_logger` example.
18*/
19
20#[cfg(all(feature = "color", feature = "humantime"))]
21fn main() {
22    use env_logger::{Builder, Env};
23
24    use std::io::Write;
25
26    fn init_logger() {
27        let env = Env::default()
28            .filter("MY_LOG_LEVEL")
29            .write_style("MY_LOG_STYLE");
30
31        Builder::from_env(env)
32            .format(|buf, record| {
33                // We are reusing `anstyle` but there are `anstyle-*` crates to adapt it to your
34                // preferred styling crate.
35                let warn_style = buf.default_level_style(log::Level::Warn);
36                let timestamp = buf.timestamp();
37
38                writeln!(
39                    buf,
40                    "My formatted log ({timestamp}): {warn_style}{}{warn_style:#}",
41                    record.args()
42                )
43            })
44            .init();
45    }
46
47    init_logger();
48
49    log::info!("a log from `MyLogger`");
50}
51
52#[cfg(not(all(feature = "color", feature = "humantime")))]
53fn main() {}
custom_format/custom_format.rs

custom_format/
custom_format.rs
