Struct LoggerBuilder

pub struct LoggerBuilder { /* private fields */ }

Available on crate feature logger only.

Implementations

impl LoggerBuilder

pub fn fmt_level(level: &Level) -> String

Return colored string of level.

• TRACE/DEBUG => Magenta
• INFO => Green
• WARN => Yellow
• ERROR => Red

pub fn new() -> Self

Create new logger instance. Default is colorful writer, INFO level, no filename and line number.

pub fn json_writer(self, writer: WriterFn) -> Self

Use custom json writer.

Warning

Do not perform heavy workloads, it can block other logs!

pub fn color_writer(self, writer: WriterFn) -> Self

Use custom colorful writer.

Warning

Do not perform heavy workloads, it can block other logs!

pub fn json(self) -> Self

Use json format writer.

pub fn level(self, level: Level) -> Self

Set log level.

pub fn filename(self) -> Self

Enable filename in the log.

pub fn line_number(self) -> Self

Enable line number in the log.

pub fn handler<F>(self, handler: F) -> Self

where F: Fn(&Map<String, Value>) -> Pin<Box<dyn Future<Output = bool>>> + Send + 'static,

Customize the handler.

The customized handler will be invoked first, even before the filter. When the return value is false, further handler will be skipped. Otherwise, normal log hander will still be invoked.

Warning

Do not perform heavy workloads, it can block other logs!

pub fn filter<F>(self, filter: F) -> Self

where F: Fn(&LogItem) -> bool + Send + 'static,

Customize the filter. Filter out unwanted logs.

When the filter function return false, no logs will be sent to the transformer.

Warning

Do not perform heavy workloads, it can block other logs!

pub fn transformer<F>(self, transformer: F) -> Self

where F: Fn(LogItem) -> LogItem + Send + 'static,

Customize the transformer. Change the logs on the fly.

After this function, LogItem will be sent to the corresponding writer.

Warning

Do not perform heavy workloads, it can block other logs!

pub fn start(self) -> (Logger, LoggerGuard)

Start logger. This method will spawn a new thread to print the log.

You should call this method only once for the entire program. For FFI library, you need to call this method once in the library code and keep the return values alive. Then customize the Self::handler and send output back to the main program.