Struct TraceContext 

pub struct TraceContext {
    pub trace_id: TraceId,
    pub span_id: SpanId,
    pub parent_span_id: SpanId,
    pub flags: u8,
}

W3C trace context in binary form.

Carries the identifiers needed to correlate spans across service boundaries. The flags field uses bit 0 as the “sampled” flag (W3C traceparent spec).

Fields

trace_id: TraceId

Trace-wide identifier (shared by all spans in the trace).

span_id: SpanId

Span identifier for the current span.

parent_span_id: SpanId

Parent span identifier (zero if this is the root span).

flags: u8

W3C trace flags. Bit 0 = sampled.

Implementations

impl TraceContext

pub fn current() -> TraceContext

Get the current thread-local trace context.

pub fn set_current(ctx: TraceContext)

Set the current thread-local trace context.

impl TraceContext

pub fn new_root(random_bytes: &[u8; 24]) -> Self

Create a new root trace context with the given random source.

Generates fresh trace_id and span_id from the provided random bytes. random_bytes must be at least 24 bytes (16 for trace_id + 8 for span_id).

pub fn child(&self, random_span_bytes: &[u8; 8]) -> Self

Create a child context within the same trace.

The child inherits trace_id and flags, gets a new span_id from the provided random bytes, and records the current span_id as its parent.

pub fn is_sampled(&self) -> bool

Whether the sampled flag is set.

pub fn set_sampled(&mut self, sampled: bool)

Set or clear the sampled flag.

pub fn encode(&self) -> [u8; 32]

Encode to a 32-byte binary representation.

Layout: [version:1][trace_id:16][span_id:8][flags:1][reserved:6]

pub fn decode(buf: &[u8; 32]) -> Result<Self, TraceContextError>

Decode from a 32-byte binary representation.

pub fn to_w3c_string(&self) -> String

Format as a W3C traceparent string: 00-{trace_id}-{span_id}-{flags}.

Returns a fixed-length 55-character string.

pub fn from_w3c_string(s: &str) -> Result<Self, TraceContextError>

Parse a W3C traceparent string.

Expected format: {version:2}-{trace_id:32}-{span_id:16}-{flags:2} (55 characters total).

pub fn is_empty(&self) -> bool

Check if this context has all-zero IDs (i.e. no trace context was set).

Trait Implementations

impl Clone for TraceContext

fn clone(&self) -> TraceContext

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TraceContext

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

Formats the value using the given formatter.

impl Default for TraceContext

fn default() -> Self

Returns the “default value” for a type.

impl Display for TraceContext

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

Formats the value using the given formatter.

impl PartialEq for TraceContext

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for TraceContext

impl Eq for TraceContext

impl StructuralPartialEq for TraceContext