Revert "ref(spans): Remove the otel spans endpoint (#3973)"

This reverts commit 44186da.

Cargo.toml

@@ -130,6 +130,7 @@ pin-project-lite = "0.2.12"
 pretty-hex = "0.4.1"
 priority-queue = "2.0.3"
 proc-macro2 = "1.0.8"
+prost = "0.11.9"
 psl = "2.1.33"
 quote = "1.0.2"
 r2d2 = "0.8.10"

relay-server/Cargo.toml

@@ -57,6 +57,7 @@ once_cell = { workspace = true }
 papaya = { workspace = true }
 pin-project-lite = { workspace = true }
 priority-queue = { workspace = true }
+prost = { workspace = true }
 rand = { workspace = true }
 rayon = { workspace = true }
 regex = { workspace = true }

relay-server/src/endpoints/mod.rs

@@ -17,6 +17,7 @@ mod nel;
 mod project_configs;
 mod public_keys;
 mod security_report;
+mod spans;
 mod statics;
 mod store;
 mod unreal;
@@ -74,6 +75,7 @@ pub fn routes(config: &Config) -> Router<ServiceState>{
         .route("/api/:project_id/minidump/", minidump::route(config))
         .route("/api/:project_id/events/:event_id/attachments/", post(attachments::handle))
         .route("/api/:project_id/unreal/:sentry_key/", unreal::route(config))
+        .route("/api/:project_id/spans/", spans::route(config))
         // NOTE: If you add a new (non-experimental) route here, please also list it in
         // https://github.com/getsentry/sentry-docs/blob/master/docs/product/relay/operating-guidelines.mdx
         .route_layer(middlewares::cors());

relay-server/src/endpoints/spans.rs

@@ -0,0 +1,62 @@
+use axum::extract::{DefaultBodyLimit, Json, Request};
+use axum::http::StatusCode;
+use axum::response::IntoResponse;
+use axum::routing::{post, MethodRouter};
+use axum::RequestExt;
+use bytes::Bytes;
+use prost::Message;
+use relay_config::Config;
+use relay_dynamic_config::Feature;
+use relay_spans::otel_trace::TracesData;
+
+use crate::endpoints::common;
+use crate::envelope::{ContentType, Envelope, Item, ItemType};
+use crate::extractors::{RawContentType, RequestMeta};
+use crate::service::ServiceState;
+use crate::utils::ApiErrorResponse;
+
+async fn handle(
+    state: ServiceState,
+    content_type: RawContentType,
+    meta: RequestMeta,
+    request: Request,
+) -> axum::response::Result<impl IntoResponse> {
+    let trace: TracesData = if content_type.as_ref().starts_with("application/json") {
+        let Json(trace) = request.extract().await?;
+        trace
+    } else if content_type.as_ref().starts_with("application/x-protobuf") {
+        // let mut bytes: Bytes = Bytes::from_request(req, state).await?;
+        // let Protobuf(trace) = request.extract().await?;
+        let mut bytes: Bytes = request.extract().await?;
+        Message::decode(&mut bytes).map_err(|e| {
+            (
+                StatusCode::UNPROCESSABLE_ENTITY,
+                ApiErrorResponse::from_error(&e),
+            )
+        })?
+    } else {
+        return Ok(StatusCode::UNSUPPORTED_MEDIA_TYPE);
+    };
+
+    let mut envelope = Envelope::from_request(None, meta);
+    envelope.require_feature(Feature::OtelEndpoint);
+    for resource_span in trace.resource_spans {
+        for scope_span in resource_span.scope_spans {
+            for span in scope_span.spans {
+                let Ok(payload) = serde_json::to_vec(&span) else {
+                    continue;
+                };
+                let mut item = Item::new(ItemType::OtelSpan);
+                item.set_payload(ContentType::Json, payload);
+                envelope.add_item(item);
+            }
+        }
+    }
+    common::handle_envelope(&state, envelope).await?;
+
+    Ok(StatusCode::ACCEPTED)
+}
+
+pub fn route(config: &Config) -> MethodRouter<ServiceState> {
+    post(handle).route_layer(DefaultBodyLimit::max(config.max_span_size()))
+}