feat(tvix/tracing): http propagation for axum r/8384

It introduces a new accept_trace function for axum0.7 which can be used
to accept a header trace from a received request. This function can be
used for tonic 0.12 once that version is released, and the specific
`accept_trace` function within `tvix_tracing::propagate::tonic` can then
be removed.

This also integrates http propagation into the nar_bridge crate.

Change-Id: I46dcc797d494bb3977c2633753e7060d88d29129
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11925
Reviewed-by: Brian Olsen <me@griff.name>
Tested-by: BuildkiteCI
Reviewed-by: Simon Hauser <simon.hauser@helsinki-systems.de>
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 2 insertions, 3 deletions

diff --git a/tvix/tracing/src/propagate/mod.rs b/tvix/tracing/src/propagate/mod.rs
index 9a7e4332b637..2e56a832e5b7 100644
--- a/tvix/tracing/src/propagate/mod.rs
+++ b/tvix/tracing/src/propagate/mod.rs
@@ -4,6 +4,5 @@ pub mod tonic;
 #[cfg(feature = "reqwest")]
 pub mod reqwest;
 
-// TODO: Helper library for axum or another http server, see
-// https://github.com/hseeberger/hello-tracing-rs/blob/main/hello-tracing-common/src/otel/http.rs
-// as an example and we can reuse tonic::accept_trace fun, at least for a tower::ServiceBuilder
+#[cfg(feature = "axum")]
+pub mod axum;