Fix span link deserialization when missing optional fields (#887)

trace-protobuf/build.rs

@@ -54,6 +54,10 @@ fn generate_protobuf() {
     config.type_attribute("TraceChunk", "#[derive(Deserialize, Serialize)]");
 
     config.type_attribute("SpanLink", "#[derive(Deserialize, Serialize)]");
+    config.field_attribute(".pb.SpanLink.traceID_high", "#[serde(default)]");
+    config.field_attribute(".pb.SpanLink.attributes", "#[serde(default)]");
+    config.field_attribute(".pb.SpanLink.tracestate", "#[serde(default)]");
+    config.field_attribute(".pb.SpanLink.flags", "#[serde(default)]");
 
     config.type_attribute("Span", "#[derive(Deserialize, Serialize)]");
     config.field_attribute(

trace-protobuf/src/pb.rs

@@ -29,6 +29,7 @@ pub struct SpanLink {
     ///
     /// Optional. The high 64 bits of a referenced trace id.
     #[prost(uint64, tag = "2")]
+    #[serde(default)]
     pub trace_id_high: u64,
     /// @gotags: json:"span_id" msg:"span_id"
     ///
@@ -39,6 +40,7 @@ pub struct SpanLink {
     ///
     /// Optional. Simple mapping of keys to string values.
     #[prost(map = "string, string", tag = "4")]
+    #[serde(default)]
     pub attributes: ::std::collections::HashMap<
         ::prost::alloc::string::String,
         ::prost::alloc::string::String,
@@ -47,11 +49,13 @@ pub struct SpanLink {
     ///
     /// Optional. W3C tracestate.
     #[prost(string, tag = "5")]
+    #[serde(default)]
     pub tracestate: ::prost::alloc::string::String,
     /// @gotags: msg:"flags,omitempty"
     ///
     /// Optional. W3C trace flags. If set, the high bit (bit 31) must be set.
     #[prost(uint32, tag = "6")]
+    #[serde(default)]
     pub flags: u32,
 }
 #[derive(Deserialize, Serialize)]

trace-utils/src/trace_utils.rs

@@ -902,6 +902,64 @@ mod tests {
         }
     }
 
+    #[tokio::test]
+    async fn test_get_traces_from_request_body_with_span_links() {
+        let trace_input = json!([[{
+            "service": "test-service",
+            "name": "test-name",
+            "resource": "test-resource",
+            "trace_id": 111,
+            "span_id": 222,
+            "parent_id": 333,
+            "start": 1,
+            "duration": 5,
+            "error": 0,
+            "meta": {},
+            "metrics": {},
+            "span_links": [{
+                "trace_id": 999,
+                "span_id": 888,
+                "trace_id_high": 777,
+                "attributes": {"key": "value"},
+                "tracestate": "vendor=value"
+                // flags field intentionally omitted
+            }]
+        }]]);
+
+        let expected_output = vec![vec![pb::Span {
+            service: "test-service".to_string(),
+            name: "test-name".to_string(),
+            resource: "test-resource".to_string(),
+            trace_id: 111,
+            span_id: 222,
+            parent_id: 333,
+            start: 1,
+            duration: 5,
+            error: 0,
+            meta: HashMap::new(),
+            metrics: HashMap::new(),
+            meta_struct: HashMap::new(),
+            r#type: String::new(),
+            span_links: vec![pb::SpanLink {
+                trace_id: 999,
+                span_id: 888,
+                trace_id_high: 777,
+                attributes: HashMap::from([("key".to_string(), "value".to_string())]),
+                tracestate: "vendor=value".to_string(),
+                flags: 0, // Should default to 0 when omitted
+            }],
+        }]];
+
+        let bytes = rmp_serde::to_vec(&trace_input).unwrap();
+        let request = Request::builder()
+            .body(hyper::body::Body::from(bytes))
+            .unwrap();
+
+        let res = get_traces_from_request_body(request.into_body()).await;
+        assert!(res.is_ok(), "Failed to deserialize: {:?}", res);
+        assert_eq!(res.unwrap().1, expected_output);
+    }
+
     #[test]
     fn test_get_root_span_index_from_complete_trace() {
         let trace = vec![