Struct Logger 

pub struct Logger { /* private fields */ }

Builder for an opinionated tracing subscriber.

By default the subscriber writes INFO level events to stdout and does not write to a file. Each log line is prefixed with the elapsed wall-clock time since the subscriber was initialized, formatted as HHh MMm SSs. This column can be restarted at any time with Logger::reset_time.

Implementations

impl Logger

pub fn new() -> Self

Create a new Logger builder with default settings (stdout at INFO).

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

Set the minimum level of events to record.

pub fn stdout(self, enable: bool) -> Self

Enable or disable the stdout layer. Enabled by default.

pub fn file<P: AsRef<Path>>(self, path: P) -> Self

Write logs to the given file path. Parent directories are created as needed and the file is truncated on open.

pub fn no_file(self) -> Self

Disable writing logs to a file.

pub fn directives(self, directives: impl Into<String>) -> Self

Override the additional EnvFilter directives appended after the level.

Defaults to "diffsol=off". Pass an empty string to disable the default directives entirely. The RUST_LOG environment variable, if set, takes precedence over the configured level and directives.

pub fn init(self) -> Result<()>

Install the configured subscriber as the global default.

Returns an error if a log file is configured but cannot be opened. Silently does nothing if a global subscriber is already installed, which makes the subscriber safe to reuse across back-to-back runs.

pub fn reset_time()

Restart the elapsed-time column so subsequent log lines count from now.

The leading HHh MMm SSs column is process-wide and shared by every layer of the installed subscriber. Calling this resets that column to 00h 00m 00s, which is useful before a fresh run when a single subscriber is reused across back-to-back fits.

This is an associated function rather than a method because the column lives in process-wide subscriber state, not on a Logger instance (which is consumed by Logger::init).

Trait Implementations

impl Clone for Logger

fn clone(&self) -> Logger

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Logger

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

Formats the value using the given formatter.

impl Default for Logger

fn default() -> Self

Returns the “default value” for a type.