Struct TracePropagationInterceptor 

pub struct TracePropagationInterceptor;

Writes the ambient CurrentTrace onto each outbound request.

With no scope open it adds nothing, so a client used outside a traced call is unaffected. It never overwrites a traceparent a caller set on the request itself — an explicit header is a decision, and silently replacing it would move the callee into a different trace than the one its caller asked for.

That guard is case-insensitive, because the header name is. W3C Trace Context §3.2.1 and §3.3.1 both say: “Vendors MUST expect the header name in any case (upper, lower, mixed), and SHOULD send the header name in lowercase.” A case-sensitive lookup against the lowercase literal would miss a caller’s Traceparent and write a second one, and both HTTP transports build the request with hyper::Request::builder().header(..), which appends rather than replaces — so the peer would receive two traceparent fields and pick whichever its own parser happened to.

One transport is outside its reach, and says so in its own module docs: WebSocketTransport (behind the websocket feature) cannot carry a per-request header at all, so nothing this interceptor writes reaches the wire on an established WebSocket connection.

Implementations

impl TracePropagationInterceptor

pub const fn new() -> TracePropagationInterceptor

Creates the interceptor.

Trait Implementations

impl CallInterceptor for TracePropagationInterceptor

fn before<'a>( &'a self, req: &'a mut ClientRequest, ) -> impl Future<Output = Result<(), ClientError>> + Send + 'a

Called before the request is sent.

fn after<'a>( &'a self, _resp: &'a ClientResponse, ) -> impl Future<Output = Result<(), ClientError>> + Send + 'a

Called after a successful response is received.

fn on_error<'a>( &'a self, req: &'a ClientRequest, err: &'a ClientError, ) -> impl Future<Output = ()> + Send + 'a

Called when the transport returns an error for a request this chain’s before hooks saw, in reverse registration order like after.

impl Clone for TracePropagationInterceptor

fn clone(&self) -> TracePropagationInterceptor

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TracePropagationInterceptor

impl Debug for TracePropagationInterceptor

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

Formats the value using the given formatter.

impl Default for TracePropagationInterceptor

fn default() -> TracePropagationInterceptor

Returns the “default value” for a type.