feat(WO-1143): determine Onset's SpanKind, serialize to JS

src/workerd/api/tests/tail-worker-test-receiver.js

@@ -34,7 +34,7 @@ export const test = {
     // Number of traces based on how often main tail worker is invoked from previous tests
     let numTraces = 32;
     let basicTrace =
-      '{"type":"onset","executionModel":"stateless","spanId":"0000000000000000","scriptTags":[],"info":{"type":"trace","traces":[]}}{"type":"return"}{"type":"outcome","outcome":"ok","cpuTime":0,"wallTime":0}';
+      '{"type":"onset","executionModel":"stateless","spanId":"0000000000000000","scriptTags":[],"info":{"type":"trace","traces":[]},"spanKind":"server"}{"type":"return"}{"type":"outcome","outcome":"ok","cpuTime":0,"wallTime":0}';
     assert.deepStrictEqual(
       Array.from(resposeMap.values()),
       Array.from({ length: numTraces }, () => basicTrace)

src/workerd/io/trace-stream.c++

@@ -78,6 +78,12 @@ namespace {
   V(SPANCLOSE, "spanClose")                                                                        \
   V(SPANCONTEXT, "spanContext")                                                                    \
   V(SPANID, "spanId")                                                                              \
+  V(SPANKIND, "spanKind")                                                                          \
+  V(SPANKIND_CLIENT, "client")                                                                     \
+  V(SPANKIND_SERVER, "server")                                                                     \
+  V(SPANKIND_PRODUCER, "producer")                                                                 \
+  V(SPANKIND_CONSUMER, "consumer")                                                                 \
+  V(SPANKIND_INTERNAL, "internal")                                                                 \
   V(SPANOPEN, "spanOpen")                                                                          \
   V(STACK, "stack")                                                                                \
   V(STATUSCODE, "statusCode")                                                                      \
@@ -136,6 +142,22 @@ class StringCache final {
 // these structs to be bidirectional. So, instead, let's just do the simple easy thing
 // and define a set of serializers to these types.
 
+kj::LiteralStringConst spanKindToString(SpanKind kind) {
+  switch (kind) {
+    case SpanKind::CLIENT:
+      return SPANKIND_CLIENT_STR;
+    case SpanKind::SERVER:
+      return SPANKIND_SERVER_STR;
+    case SpanKind::PRODUCER:
+      return SPANKIND_PRODUCER_STR;
+    case SpanKind::CONSUMER:
+      return SPANKIND_CONSUMER_STR;
+    case SpanKind::INTERNAL:
+      return SPANKIND_INTERNAL_STR;
+  }
+  KJ_UNREACHABLE;
+}
+
 // Serialize attribute value
 jsg::JsValue ToJs(jsg::Lock& js, const Attribute::Value& value) {
   KJ_SWITCH_ONEOF(value) {
@@ -405,6 +427,7 @@ jsg::JsValue ToJs(jsg::Lock& js, const Onset& onset, StringCache& cache) {
         js.arr(onset.attributes.asPtr(),
             [&cache](jsg::Lock& js, const auto& attr) { return ToJs(js, attr, cache); }));
   }
+  obj.set(js, SPANKIND_STR, cache.get(js, spanKindToString(onset.spanKind)));
 
   return obj;
 }

src/workerd/io/tracer.c++

@@ -379,10 +379,28 @@ void WorkerTracer::setEventInfoInternal(
     auto onsetContext = tracing::InvocationSpanContext(
         context.getTraceId(), context.getInvocationId(), tracing::SpanId::nullId);
 
+    // Derive SpanKind for the root span from the handler type.
+    SpanKind onsetSpanKind = SpanKind::SERVER;
+    KJ_SWITCH_ONEOF(info) {
+      KJ_CASE_ONEOF(_, tracing::ScheduledEventInfo) {
+        onsetSpanKind = SpanKind::CONSUMER;
+      }
+      KJ_CASE_ONEOF(_, tracing::AlarmEventInfo) {
+        onsetSpanKind = SpanKind::CONSUMER;
+      }
+      KJ_CASE_ONEOF(_, tracing::QueueEventInfo) {
+        onsetSpanKind = SpanKind::CONSUMER;
+      }
+      KJ_CASE_ONEOF(_, tracing::EmailEventInfo) {
+        onsetSpanKind = SpanKind::CONSUMER;
+      }
+      KJ_CASE_ONEOF_DEFAULT { /* SERVER for fetch, jsrpc, trace, hibernatableWebSocket, etc. */ }
+    }
+
     // Not applying size accounting for Onset since it is sent separately
     writer->report(onsetContext,
         tracing::Onset(context.getSpanId(), cloneEventInfo(info), kj::mv(workerInfo),
-            attributes.releaseAsArray()),
+            attributes.releaseAsArray(), onsetSpanKind),
         timestamp, 0);
   }
 

types/defines/trace.d.ts

@@ -82,6 +82,8 @@ type EventOutcome = "ok" | "canceled" | "exception" | "unknown" | "killSwitch" |
                     "daemonDown" | "exceededCpu" | "exceededMemory" | "loadShed" |
                     "responseStreamDisconnected" | "scriptNotFound";
 
+type SpanKind = "client" | "server" | "producer" | "consumer" | "internal";
+
 interface ScriptVersion {
   readonly id: string;
   readonly tag?: string;
@@ -103,6 +105,7 @@ interface Onset {
                  ScheduledEventInfo | AlarmEventInfo | QueueEventInfo |
                  EmailEventInfo | TraceEventInfo |
                  HibernatableWebSocketEventInfo | CustomEventInfo;
+  readonly spanKind: SpanKind;
 }
 
 interface Outcome {

types/generated-snapshot/experimental/index.d.ts

@@ -14562,6 +14562,7 @@ declare namespace TailStream {
     | "loadShed"
     | "responseStreamDisconnected"
     | "scriptNotFound";
+  type SpanKind = "client" | "server" | "producer" | "consumer" | "internal";
   interface ScriptVersion {
     readonly id: string;
     readonly tag?: string;
@@ -14589,6 +14590,7 @@ declare namespace TailStream {
       | TraceEventInfo
       | HibernatableWebSocketEventInfo
       | CustomEventInfo;
+    readonly spanKind: SpanKind;
   }
   interface Outcome {
     readonly type: "outcome";

types/generated-snapshot/experimental/index.ts

@@ -14519,6 +14519,7 @@ export declare namespace TailStream {
     | "loadShed"
     | "responseStreamDisconnected"
     | "scriptNotFound";
+  type SpanKind = "client" | "server" | "producer" | "consumer" | "internal";
   interface ScriptVersion {
     readonly id: string;
     readonly tag?: string;
@@ -14546,6 +14547,7 @@ export declare namespace TailStream {
       | TraceEventInfo
       | HibernatableWebSocketEventInfo
       | CustomEventInfo;
+    readonly spanKind: SpanKind;
   }
   interface Outcome {
     readonly type: "outcome";

types/generated-snapshot/latest/index.d.ts

@@ -13868,6 +13868,7 @@ declare namespace TailStream {
     | "loadShed"
     | "responseStreamDisconnected"
     | "scriptNotFound";
+  type SpanKind = "client" | "server" | "producer" | "consumer" | "internal";
   interface ScriptVersion {
     readonly id: string;
     readonly tag?: string;
@@ -13895,6 +13896,7 @@ declare namespace TailStream {
       | TraceEventInfo
       | HibernatableWebSocketEventInfo
       | CustomEventInfo;
+    readonly spanKind: SpanKind;
   }
   interface Outcome {
     readonly type: "outcome";

types/generated-snapshot/latest/index.ts

@@ -13825,6 +13825,7 @@ export declare namespace TailStream {
     | "loadShed"
     | "responseStreamDisconnected"
     | "scriptNotFound";
+  type SpanKind = "client" | "server" | "producer" | "consumer" | "internal";
   interface ScriptVersion {
     readonly id: string;
     readonly tag?: string;
@@ -13852,6 +13853,7 @@ export declare namespace TailStream {
       | TraceEventInfo
       | HibernatableWebSocketEventInfo
       | CustomEventInfo;
+    readonly spanKind: SpanKind;
   }
   interface Outcome {
     readonly type: "outcome";