Struct flexi_logger::LogSpecification

pub struct LogSpecification { /* fields omitted */ }

Immutable struct that defines which loglines are to be written, based on the module, the log level, and the text.

The loglevel specification via string (relevant for methods parse() and env()) works essentially like with env_logger, but we are a bit more tolerant with spaces. Its functionality can be described with some Backus-Naur-form:

<log_level_spec> ::= single_log_level_spec[{,single_log_level_spec}][/<text_filter>]
<single_log_level_spec> ::= <path_to_module>|<log_level>|<path_to_module>=<log_level>
<text_filter> ::= <regex>

• Examples:

  • "info": all logs with info, warn, or error level are written
  • "crate1": all logs of this crate are written, but nothing else
  • "warn, crate2::mod_a=debug, mod_x::mod_y=trace": all crates log warnings and errors, mod_a additionally debug messages, and mod_x::mod_y is fully traced

• If you just specify the module, without log_level, all levels will be traced for this module.

• If you just specify a log level, this will be applied as default to all modules without explicit log level assigment. (You see that for modules named error, warn, info, debug or trace, it is necessary to specify their loglevel explicitly).

• The module names are compared as Strings, with the side effect that a specified module filter affects all modules whose name starts with this String.
  Example: "foo" affects e.g.

  • foo
  • foo::bar
  • foobaz (!)
  • foobaz::bar (!)

The optional text filter is applied for all modules.

Note that external module names are to be specified like in "extern crate ...", i.e., for crates with a dash in their name this means: the dash is to be replaced with the underscore (e.g. karl_heinz, not karl-heinz).

Methods

impl LogSpecification

pub fn enabled(&self, level: Level, target_module: &str) -> bool

Implementation of Log::enabled() with easier testable signature

pub fn off() -> LogSpecification

Returns a LogSpecification where all traces are switched off.

pub fn parse(spec: &str) -> Result<LogSpecification, FlexiLoggerError>

Returns a log specification from a String.

pub fn env() -> Result<LogSpecification, FlexiLoggerError>

Returns a log specification based on the value of the environment variable RUST_LOG, or an empty one.

pub fn env_or_parse<S: AsRef<str>>(     given_spec: S ) -> Result<LogSpecification, FlexiLoggerError>

Returns a log specification based on the value of the environment variable RUST_LOG, or on the given String.

pub fn ensure_specfile_is_valid(     &self,     specfile: &PathBuf ) -> Result<(), FlexiLoggerError>

If the specfile does not exist, try to create it, with the current spec as content, under the specified name.

pub fn file<P: AsRef<Path>>(     specfile: P ) -> Result<LogSpecification, FlexiLoggerError>

Reads a log specification from a file.

pub fn to_toml(&self, w: &mut dyn Write) -> Result<(), FlexiLoggerError>

Serializes itself in toml format

pub fn default(level_filter: LevelFilter) -> LogSpecBuilder

Creates a LogSpecBuilder, setting the default log level.

pub fn module_filters(&self) -> &Vec<ModuleFilter>

Provides a reference to the module filters.

pub fn text_filter(&self) -> &Option<Regex>

Provides a reference to the text filter.

Trait Implementations

impl Default for LogSpecification

fn default() -> LogSpecification

Returns the "default value" for a type.

impl Clone for LogSpecification

fn clone(&self) -> LogSpecification

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for LogSpecification

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

Formats the value using the given formatter.