Use traceparent header to get tracing.

src/filters.rs

@@ -12,6 +12,7 @@ pub fn search(db: Pool) -> impl Filter<Extract = impl Reply, Error = Rejection>
 
 pub fn search_file(db: Pool) -> impl Filter<Extract = impl Reply, Error = Rejection> + Clone {
     warp::path("file")
+        .and(with_telem())
         .and(warp::get())
         .and(warp::query::<FileSearchOpts>())
         .and(with_pool(db))
@@ -21,6 +22,7 @@ pub fn search_file(db: Pool) -> impl Filter<Extract = impl Reply, Error = Reject
 
 pub fn search_image(db: Pool) -> impl Filter<Extract = impl Reply, Error = Rejection> + Clone {
     warp::path("image")
+        .and(with_telem())
         .and(warp::post())
         .and(warp::multipart::form().max_length(1024 * 1024 * 10))
         .and(warp::query::<ImageSearchOpts>())
@@ -31,6 +33,7 @@ pub fn search_image(db: Pool) -> impl Filter<Extract = impl Reply, Error = Rejec
 
 pub fn search_hashes(db: Pool) -> impl Filter<Extract = impl Reply, Error = Rejection> + Clone {
     warp::path("hashes")
+        .and(with_telem())
         .and(warp::get())
         .and(warp::query::<HashSearchOpts>())
         .and(with_pool(db))
@@ -42,6 +45,7 @@ pub fn stream_search_image(
     db: Pool,
 ) -> impl Filter<Extract = impl Reply, Error = Rejection> + Clone {
     warp::path("stream")
+        .and(with_telem())
         .and(warp::post())
         .and(warp::multipart::form().max_length(1024 * 1024 * 10))
         .and(with_pool(db))
@@ -56,3 +60,27 @@ fn with_api_key() -> impl Filter<Extract = (String,), Error = Rejection> + Clone
 fn with_pool(db: Pool) -> impl Filter<Extract = (Pool,), Error = Infallible> + Clone {
     warp::any().map(move || db.clone())
 }
+
+fn with_telem() -> impl Filter<Extract = (crate::Span,), Error = Rejection> + Clone {
+    warp::any()
+        .and(warp::header::optional("traceparent"))
+        .map(|traceparent: Option<String>| {
+            use opentelemetry::api::trace::{provider::Provider, tracer::Tracer, propagator::HttpTextFormat};
+
+            let mut headers = std::collections::HashMap::new();
+            headers.insert("Traceparent", traceparent.unwrap_or_else(String::new));
+
+            let propagator = opentelemetry::api::distributed_context::http_trace_context_propagator::HTTPTraceContextPropagator::new();
+            let context = propagator.extract(&headers);
+
+            if context.is_valid() {
+                let tracer = opentelemetry::global::trace_provider().get_tracer("api");
+                let span = tracer.start("context", Some(context));
+                tracer.mark_span_as_active(&span);
+
+                Some(span)
+            } else {
+                None
+            }
+        })
+}

src/handlers.rs

@@ -76,8 +76,9 @@ async fn hash_input(form: warp::multipart::FormData) -> (i64, img_hash::ImageHas
     (i64::from_be_bytes(buf), hash)
 }
 
-#[tracing::instrument(skip(form, pool, api_key))]
+#[tracing::instrument(skip(_telem, form, pool, api_key))]
 pub async fn search_image(
+    _telem: crate::Span,
     form: warp::multipart::FormData,
     opts: ImageSearchOpts,
     pool: Pool,
@@ -123,8 +124,9 @@ pub async fn search_image(
     Ok(warp::reply::json(&similarity))
 }
 
-#[tracing::instrument(skip(form, pool, api_key))]
+#[tracing::instrument(skip(_telem, form, pool, api_key))]
 pub async fn stream_image(
+    _telem: crate::Span,
     form: warp::multipart::FormData,
     pool: Pool,
     api_key: String,
@@ -158,8 +160,9 @@ fn sse_matches(
     Ok(warp::sse::json(items))
 }
 
-#[tracing::instrument(skip(form, db, api_key))]
+#[tracing::instrument(skip(_telem, form, db, api_key))]
 pub async fn search_hashes(
+    _telem: crate::Span,
     opts: HashSearchOpts,
     db: Pool,
     api_key: String,
@@ -190,8 +193,9 @@ pub async fn search_hashes(
     Ok(warp::reply::json(&matches))
 }
 
-#[tracing::instrument(skip(db, api_key))]
+#[tracing::instrument(skip(_telem, db, api_key))]
 pub async fn search_file(
+    _telem: crate::Span,
     opts: FileSearchOpts,
     db: Pool,
     api_key: String,

src/main.rs

@@ -10,6 +10,8 @@ mod utils;
 
 use warp::Filter;
 
+type Span = Option<opentelemetry::global::BoxedSpan>;
+
 fn configure_tracing() {
     use opentelemetry::{
         api::{KeyValue, Provider, Sampler},
@@ -43,7 +45,9 @@ fn configure_tracing() {
         })
         .build();
 
-    let tracer = provider.get_tracer("api");
+    opentelemetry::global::set_provider(provider);
+
+    let tracer = opentelemetry::global::trace_provider().get_tracer("api");
 
     let telem_layer = tracing_opentelemetry::OpentelemetryLayer::with_tracer(tracer);
     let fmt_layer = tracing_subscriber::fmt::Layer::default();