Struct Builder 

pub struct Builder { /* private fields */ }

A struct to initialize the logger for log crate.

Implementations

impl Builder

pub fn new() -> Self

Returns a Builder with default configuration. The default configuration is:

• level filter: get from the environment variable by get_env_level().
• default writer: write to stderr in JSON format.

pub fn with_level(level: &str) -> Self

Returns a Builder with a given level filter. level is a string that can be parsed to log::LevelFilter. Such as “OFF”, “ERROR”, “WARN”, “INFO”, “DEBUG”, “TRACE”, ignore ascii case.

pub fn with_default_writer(self, writer: Box<dyn Writer>) -> Self

Returns a Builder with a given writer as default writer.

pub fn with_target_writer(self, targets: &str, writer: Box<dyn Writer>) -> Self

Returns a Builder with a given targets pattern and writer. targets is a pattern that be used to test log target, if true, the log will be written to the writer. writer is a boxed struct that implements the Writer trait. You can call this method multiple times in order to add multiple writers.

targets pattern examples:

• "api": match the target “api”.
• "api,db": match the target “api” or “db”.
• "api*,db": match the target “db”, “api”, “api::v1”, “api::v2”, etc.
• "*": match all targets.

pub fn with_msg_field(self) -> Self

Use “msg” field for log message instead of “message”.

pub fn build(self) -> impl Log

Builds the logger without registering it in the log crate.

Unlike Builder::init and Builder::try_init this does not register the logger into the log system, allowing it to be combined with other logging crates.

pub fn init(self)

Initialize the logger for log crate.

See the crate level documentation for more.

Panics

This will panic if the logger fails to initialize. Use Builder::try_init if you want to handle the error yourself.

pub fn try_init(self) -> Result<(), SetLoggerError>

Try to initialize the logger for log crate.

Unlike Builder::init this doesn’t panic when the logger fails to initialize. See the crate level documentation for more.

Trait Implementations

impl Default for Builder

fn default() -> Self

Returns the “default value” for a type.