Struct Span 

pub struct Span { /* private fields */ }

A single open span. Create one with span or client_span (or Span::new for full control over SpanKind); it becomes the “current” span on this thread until it’s dropped (or Span::end is called explicitly, which is equivalent).

Nesting: creating a Span while another is already active makes the new one its child — the child inherits the parent’s trace_id and sampling decision, and parent_span_id() is the parent’s span_id(). Dropping the child makes the parent “current” again.

Not Send: a Span must be dropped on the thread that created it, since dropping pops a thread-local stack — moving one to another thread and dropping it there would corrupt that thread’s stack.

Example

use rust_web_server::otel;

let span = otel::span("db.query");
span.set_attribute("db.statement", "SELECT 1");
// ... do the work ...
span.end(); // or just let it drop at the end of scope

Implementations

impl Span

pub fn new(name: &str, kind: SpanKind) -> Span

Start a new span with an explicit SpanKind. Prefer span or client_span for the common cases.

pub fn set_attribute(&self, key: &str, value: impl Into<AttributeValue>)

Attach a key/value attribute. Repeated keys are appended, not deduplicated — matching this module’s existing “loosely OTLP” style.

pub fn set_error(&self)

Mark this span as failed (OTLP Status.code = 2, Error).

pub fn record_error(&self, message: &str)

Mark this span as failed and attach an error.message attribute.

pub fn trace_id(&self) -> [u8; 16]

pub fn span_id(&self) -> [u8; 8]

pub fn parent_span_id(&self) -> Option<[u8; 8]>

pub fn end(self)

End the span now. Equivalent to letting it drop at the end of scope — both run the exact same recording logic — but useful when you want the span’s duration to stop before other work continues in the same scope.

Trait Implementations

impl Drop for Span

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.