Struct Metadata 

#[non_exhaustive]
pub struct Metadata<'a> {
    pub level: Level,
    pub target: &'a str,
    pub file: Option<&'a str>,
    pub line: Option<u32>,
    pub timestamp_unix_nanos: Option<u128>,
}

Metadata describing the origin and severity of a record.

level and target are required; the rest is best-effort context. The logging macros populate file and line automatically and the crate::Logger fills in timestamp_unix_nanos when timestamps are enabled.

The struct is #[non_exhaustive] so new metadata can be added in a minor release. Build it with Metadata::new and the with_* methods; every field stays publicly readable.

Examples

use log_io::{Level, Metadata};

let meta = Metadata::new(Level::Warn, "app::db")
    .with_location("src/db.rs", 42)
    .with_timestamp(1_700_000_000_000_000_000);
assert_eq!(meta.target, "app::db");
assert_eq!(meta.line, Some(42));

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

level: Level

Severity of the record.

target: &'a str

Logical target. Typically the module path, but callers are free to use a domain-specific identifier for filtering.

file: Option<&'a str>

Source file path, if known.

line: Option<u32>

Source line number, if known.

timestamp_unix_nanos: Option<u128>

Nanoseconds since the Unix epoch, if known. Populated by the logger when std is available and timestamps are enabled. None means the consumer should supply its own clock (typical in no_std builds).

Implementations

impl<'a> Metadata<'a>

pub const fn new(level: Level, target: &'a str) -> Self

Build minimal metadata containing only level and target. All optional fields are None.

pub const fn with_location(self, file: &'a str, line: u32) -> Self

Replace the source location.

pub const fn with_timestamp(self, ts_unix_nanos: u128) -> Self

Replace the timestamp (nanoseconds since the Unix epoch).

Trait Implementations

impl<'a> Clone for Metadata<'a>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for Metadata<'a>

impl<'a> Debug for Metadata<'a>

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

Formats the value using the given formatter.

impl<'a> PartialEq for Metadata<'a>

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<'a> StructuralPartialEq for Metadata<'a>