Struct SpanGuard 

pub struct SpanGuard { /* private fields */ }

RAII guard that ends the span when dropped.

Use builder-style methods to attach data before the span completes.

Implementations

impl SpanGuard

pub fn id(&self) -> &str

Get the span ID.

pub fn parent_id(&self) -> Option<&str>

Get the parent span ID.

pub fn with_tokens(self, usage: SpanTokenUsage) -> Self

Set token usage on this span.

pub fn with_cost(self, cost: f64) -> Self

Set cost on this span.

When set, end uses this value verbatim. When left None, cost is auto-estimated from token usage + gen_ai model at span end (E3).

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

Set the gen_ai request model (used for auto cost estimation).

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

Set the gen_ai response model (fallback for auto cost estimation).

pub fn with_metadata(self, key: &str, value: Value) -> Self

Add a metadata key-value pair.

pub fn set_error(&mut self, msg: &str)

Mark this span as having errored.

pub fn end(self)

Manually end the span now instead of waiting for Drop.

Trait Implementations

impl Drop for SpanGuard

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.