Enum Target 

pub enum Target {
    Field(String),
    Attr(String),
}

What a term filters on.

Variants

Field(String)

A column of the signal’s root table, by name.

Attr(String)

An attribute key, looked up at every level the signal has — record, resource, scope, and on traces the span’s own events and links — and unioned.

Whether service.name is a resource attribute is a detail of whoever configured the SDK, and users do not know it. Searching all of them is what every usable tracing UI does; the star schema makes it a handful of scans of tables that are tiny next to the root.

The child levels are not a nicety. Span.recordException — the one API call behind most of the spans anyone goes looking for — writes exception.type to a span event, so leaving events out made the commonest question in a tracing UI return an empty list while the value was visible in events[].attributes of the very same response. A match on a child selects the span it hangs off, which is the row the caller asked for.

Trait Implementations

impl Clone for Target

fn clone(&self) -> Target

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Target

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

Formats the value using the given formatter.