Add telemetry

1 files changed, 30 insertions, 1 deletions

diff --git a/src/client.rs b/src/client.rs
index ca1bcf9..7ef772d 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -125,10 +125,39 @@ impl ClientConn {
 			.next_query_number
 			.fetch_add(1, atomic::Ordering::Relaxed);
 
-		let mut bytes = vec![prio, path.as_bytes().len() as u8];
+		cfg_if::cfg_if! {
+			if #[cfg(feature = "telemetry")] {
+				use opentelemetry::{trace::{TraceId, TraceContextExt}, Context};
+				let trace_id_int = Context::current()
+					.span()
+					.span_context()
+					.trace_id();
+				let trace_id = if trace_id_int == TraceId::INVALID {
+					None
+				} else {
+					Some(trace_id_int.to_bytes().to_vec())
+				};
+			} else {
+				let trace_id: Option<Vec<u8>> = None;
+			}
+		};
+
+		// Encode request
+		let mut bytes = vec![];
+
+		bytes.extend_from_slice(&[prio, path.as_bytes().len() as u8]);
 		bytes.extend_from_slice(path.as_bytes());
+
+		if let Some(by) = trace_id {
+			bytes.push(by.len() as u8);
+			bytes.extend(by);
+		} else {
+			bytes.push(0);
+		}
+
 		bytes.extend_from_slice(&rmp_to_vec_all_named(rq)?[..]);
 
+		// Send request through
 		let (resp_send, resp_recv) = oneshot::channel();
 		let old = self.inflight.lock().unwrap().insert(id, resp_send);
 		if let Some(old_ch) = old {