Struct HumanFormat 

pub struct HumanFormat { /* private fields */ }

Available on crate feature human only.

Human-readable formatter.

Message and target are written as-is except that control characters, DEL, C1 controls, U+2028/U+2029 and bidi controls are escaped (\n, \x1b, \u{85}, …), so hostile input can neither break the one-record-per-line layout nor drive the terminal. Values are quoted when they are empty or contain whitespace, =, ", \ or a special character. Keys are sanitized: whitespace, =, " and special characters become _.

Backslashes in unquoted text are not escaped, so a message that literally contains \n renders the same as one containing a newline. The format is meant for people; use JSON or logfmt where output must be parsed back exactly.

Colour is off by default. HumanFormat::color turns ANSI colour on for the level column (and dims the target); the LoggerBuilder::stdout_human / stderr_human shortcuts enable it automatically when the stream is a terminal (see ColorChoice, available with the std feature).

Examples

use log_io::format::{Format, HumanFormat};
use log_io::{Field, Level, Metadata, Record};

let fields = [Field::new("port", 8080_u32), Field::new("note", "two words")];
let record = Record::new(Metadata::new(Level::Info, "app"), "ok\x1b[2J", &fields);

let mut out = String::new();
HumanFormat::new().write_record(&record, &mut out)?;
assert_eq!(out, "INFO  [app] ok\\x1b[2J port=8080 note=\"two words\"\n");

Implementations

impl HumanFormat

pub const fn new() -> Self

New formatter: target shown, source location hidden, no colour.

pub const fn show_target(self, enabled: bool) -> Self

Toggle the [target] column. The column is always omitted for records with an empty target.

pub const fn show_source_location(self, enabled: bool) -> Self

Toggle the (file:line) suffix for records that carry a source location.

pub const fn color(self, enabled: bool) -> Self

Toggle ANSI colour: the level is coloured (ERROR red, WARN yellow, INFO green, DEBUG blue, TRACE magenta) and the target is dimmed. Only the formatter emits escape sequences; user text is always escaped, so it cannot add its own.

pub const fn is_color(&self) -> bool

Whether ANSI colour is enabled.

Trait Implementations

impl Clone for HumanFormat

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for HumanFormat

impl Debug for HumanFormat

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

Formats the value using the given formatter.

impl Default for HumanFormat

fn default() -> Self

Returns the “default value” for a type.

impl Format for HumanFormat

fn write_record(&self, record: &Record<'_>, writer: &mut dyn Write) -> Result

Write record to writer.

fn write_record_generic<W: Write>( &self, record: &Record<'_>, writer: &mut W, ) -> Result

Statically dispatched variant of Format::write_record.