Struct env_logger::fmt::Style

source · [−]

pub struct Style { /* private fields */ }

Expand description

A set of styles to apply to the terminal output.

Call Formatter::style to get a Style and use the builder methods to set styling properties, like color and weight. To print a value using the style, wrap it in a call to value when the log record is formatted.

Examples

Create a bold, red colored style and use it to print the log level:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut level_style = buf.style();

    level_style.set_color(Color::Red).set_bold(true);

    writeln!(buf, "{}: {}",
        level_style.value(record.level()),
        record.args())
});

Styles can be re-used to output multiple values:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut bold = buf.style();

    bold.set_bold(true);

    writeln!(buf, "{}: {} {}",
        bold.value(record.level()),
        bold.value("some bold text"),
        record.args())
});

Implementations

source

impl Style

source

pub fn set_color(&mut self, color: Color) -> &mut Style

Set the text color.

Examples

Create a style with red text:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_color(Color::Red);

    writeln!(buf, "{}", style.value(record.args()))
});

source

pub fn set_bold(&mut self, yes: bool) -> &mut Style

Set the text weight.

If yes is true then text will be written in bold. If yes is false then text will be written in the default weight.

Examples

Create a style with bold text:

use std::io::Write;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_bold(true);

    writeln!(buf, "{}", style.value(record.args()))
});

source

pub fn set_intense(&mut self, yes: bool) -> &mut Style

Set the text intensity.

If yes is true then text will be written in a brighter color. If yes is false then text will be written in the default color.

Examples

Create a style with intense text:

use std::io::Write;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_intense(true);

    writeln!(buf, "{}", style.value(record.args()))
});

source

pub fn set_bg(&mut self, color: Color) -> &mut Style

Set the background color.

Examples

Create a style with a yellow background:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_bg(Color::Yellow);

    writeln!(buf, "{}", style.value(record.args()))
});

source

pub fn value<T>(&self, value: T) -> StyledValue<'_, T>

Wrap a value in the style.

The same Style can be used to print multiple different values.

Examples

Create a bold, red colored style and use it to print the log level:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_color(Color::Red).set_bold(true);

    writeln!(buf, "{}: {}",
        style.value(record.level()),
        record.args())
});