Struct Builder

pub struct Builder { /* private fields */ }

A builder for a log filter.

It can be used to parse a set of directives from a string before building a Filter instance.

Example

use env_logger::filter::Builder;

let mut builder = Builder::new();

// Parse a logging filter from an environment variable.
if let Ok(rust_log) = env::var("RUST_LOG") {
    builder.parse(&rust_log);
}

let filter = builder.build();

Implementations

impl Builder

pub fn new() -> Builder

Initializes the filter builder with defaults.

pub fn from_env(env: &str) -> Builder

Initializes the filter builder from an environment.

pub fn filter_module(&mut self, module: &str, level: LevelFilter) -> &mut Self

Adds a directive to the filter for a specific module.

pub fn filter_level(&mut self, level: LevelFilter) -> &mut Self

Adds a directive to the filter for all modules.

pub fn filter(&mut self, module: Option<&str>, level: LevelFilter) -> &mut Self

Adds a directive to the filter.

The given module (if any) will log at most the specified level provided. If no module is provided then the filter will apply to all log messages.

pub fn parse(&mut self, filters: &str) -> &mut Self

Parses the directives string.

See the Enabling Logging section for more details.

pub fn build(&mut self) -> Filter

Build a log filter.

Trait Implementations

impl Debug for Builder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Builder

fn default() -> Self

Returns the “default value” for a type.