Expose ranking metadata in request trace

crates/aether-admin/src/observability/monitoring.rs

@@ -365,6 +365,7 @@ pub fn build_admin_monitoring_trace_request_candidate_payload_with_key_accounts(
         "error_message": candidate.error_message,
         "latency_ms": candidate.latency_ms,
         "concurrent_requests": candidate.concurrent_requests,
+        "ranking": build_admin_monitoring_trace_candidate_ranking(candidate.extra_data.as_ref()),
         "extra_data": build_admin_monitoring_trace_candidate_extra_data(candidate.extra_data.as_ref(), usage),
         "created_at": unix_ms_to_rfc3339(candidate.created_at_unix_ms),
         "started_at": candidate.started_at_unix_ms.and_then(unix_ms_to_rfc3339),
@@ -417,6 +418,41 @@ fn admin_monitoring_candidate_status_rank(status: RequestCandidateStatus) -> u8
     }
 }
 
+fn build_admin_monitoring_trace_candidate_ranking(existing: Option<&Value>) -> Value {
+    let Some(object) = existing.and_then(Value::as_object) else {
+        return Value::Null;
+    };
+
+    let mut ranking = serde_json::Map::new();
+    if let Some(ranking_mode) = json_string_field(object, "ranking_mode") {
+        ranking.insert("mode".to_string(), Value::String(ranking_mode));
+    }
+    if let Some(priority_mode) = json_string_field(object, "priority_mode") {
+        ranking.insert("priority_mode".to_string(), Value::String(priority_mode));
+    }
+    if let Some(ranking_index) = json_u64_field(object, "ranking_index") {
+        ranking.insert("index".to_string(), Value::Number(ranking_index.into()));
+    }
+    if let Some(priority_slot) = json_i64_field(object, "priority_slot") {
+        ranking.insert(
+            "priority_slot".to_string(),
+            Value::Number(priority_slot.into()),
+        );
+    }
+    if let Some(promoted_by) = json_string_field(object, "promoted_by") {
+        ranking.insert("promoted_by".to_string(), Value::String(promoted_by));
+    }
+    if let Some(demoted_by) = json_string_field(object, "demoted_by") {
+        ranking.insert("demoted_by".to_string(), Value::String(demoted_by));
+    }
+
+    if ranking.is_empty() {
+        Value::Null
+    } else {
+        Value::Object(ranking)
+    }
+}
+
 fn build_admin_monitoring_trace_candidate_extra_data(
     existing: Option<&Value>,
     usage: Option<&StoredRequestUsageAudit>,
@@ -461,6 +497,31 @@ fn build_admin_monitoring_trace_candidate_extra_data(
     }
 }
 
+fn json_string_field(object: &serde_json::Map<String, Value>, key: &str) -> Option<String> {
+    object
+        .get(key)
+        .and_then(Value::as_str)
+        .map(str::trim)
+        .filter(|value| !value.is_empty())
+        .map(ToOwned::to_owned)
+}
+
+fn json_u64_field(object: &serde_json::Map<String, Value>, key: &str) -> Option<u64> {
+    match object.get(key)? {
+        Value::Number(value) => value.as_u64(),
+        Value::String(value) => value.trim().parse::<u64>().ok(),
+        _ => None,
+    }
+}
+
+fn json_i64_field(object: &serde_json::Map<String, Value>, key: &str) -> Option<i64> {
+    match object.get(key)? {
+        Value::Number(value) => value.as_i64().or_else(|| value.as_u64()?.try_into().ok()),
+        Value::String(value) => value.trim().parse::<i64>().ok(),
+        _ => None,
+    }
+}
+
 fn parse_admin_monitoring_usage_proxy_timing(usage: &StoredRequestUsageAudit) -> Option<Value> {
     admin_monitoring_header_value(usage.response_headers.as_ref(), "x-proxy-timing")
         .or_else(|| {