Preserve outbound trace activity details

Outbound send activity events now keep the lightweight activity type and actor identifiers that the debug exporter needs after the full activity JSON payload was removed from the event attributes.

#755 (comment)

Assisted-by: gpt-5.5

Author: dahlia

docs/manual/opentelemetry.md

@@ -265,11 +265,14 @@ Each span event includes attributes with detailed information:
 
  -  `activitypub.inbox.url`: The inbox URL where the activity was delivered
  -  `activitypub.activity.id`: The activity ID
+ -  `activitypub.activity.type` (optional): The qualified activity type URI
+ -  `activitypub.actor.id` (optional): The sender actor ID
 
-The `activitypub.activity.sent` event records delivery metadata only.  It does
-not include the full `activitypub.activity.json` payload; if you need the full
-outbound activity for auditing, store it in your application before delivery
-and correlate it with `activitypub.activity.id`.
+The `activitypub.activity.sent` event records delivery metadata and lightweight
+activity identifiers only.  It does not include the full
+`activitypub.activity.json` payload; if you need the full outbound activity for
+auditing, store it in your application before delivery and correlate it with
+`activitypub.activity.id`.
 
 **`activitypub.delivery.failed` event attributes:**
 
@@ -462,9 +465,17 @@ export class FedifyDebugExporter implements SpanExporter {
           const inboxUrl = event.attributes[
             "activitypub.inbox.url"
           ] as string | undefined;
+          const activityType = event.attributes[
+            "activitypub.activity.type"
+          ] as string | undefined;
+          const actorId = event.attributes[
+            "activitypub.actor.id"
+          ] as string | undefined;
           this.activities.push({
             direction: "outbound",
             activityId,
+            activityType,
+            actorId,
             inboxUrl,
             timestamp: new Date(span.startTime[0] * 1000),
           });

packages/fedify/src/federation/send.test.ts

@@ -498,6 +498,14 @@ test("sendActivity() records OpenTelemetry span events", async (t) => {
       event.attributes["activitypub.activity.id"],
       "https://example.com/activity",
     );
+    assertEquals(
+      event.attributes["activitypub.activity.type"],
+      "https://www.w3.org/ns/activitystreams#Create",
+    );
+    assertEquals(
+      event.attributes["activitypub.actor.id"],
+      "https://example.com/person",
+    );
     assertEquals(event.attributes["activitypub.activity.json"], undefined);
 
     exporter.clear();

packages/fedify/src/federation/send.ts

@@ -1,6 +1,7 @@
 import type { Recipient } from "@fedify/vocab";
 import { getLogger } from "@logtape/logtape";
 import {
+  type Attributes,
   type MeterProvider,
   type Span,
   SpanKind,
@@ -198,6 +199,29 @@ export function sendActivity(
 
 const MAX_ERROR_RESPONSE_BODY_BYTES = 1024;
 
+function getActivityActorId(activity: unknown): string | undefined {
+  if (!isRecord(activity)) return undefined;
+  return getIdValue(activity.actor);
+}
+
+function getIdValue(value: unknown): string | undefined {
+  if (typeof value === "string" && value !== "") return value;
+  if (value instanceof URL) return value.href;
+  if (Array.isArray(value)) {
+    for (const item of value) {
+      const id = getIdValue(item);
+      if (id != null) return id;
+    }
+    return undefined;
+  }
+  if (isRecord(value)) return getIdValue(value.id);
+  return undefined;
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value != null;
+}
+
 async function readLimitedResponseBody(
   response: Response,
   maxBytes: number,
@@ -340,10 +364,18 @@ async function sendActivityInternal(
     deliverySuccess = true;
 
     // Record the sent activity with delivery details
-    span.addEvent("activitypub.activity.sent", {
+    const eventAttributes: Attributes = {
       "activitypub.inbox.url": inbox.href,
       "activitypub.activity.id": activityId ?? "",
-    });
+    };
+    if (activityType != null) {
+      eventAttributes["activitypub.activity.type"] = activityType;
+    }
+    const actorId = getActivityActorId(activity);
+    if (actorId != null) {
+      eventAttributes["activitypub.actor.id"] = actorId;
+    }
+    span.addEvent("activitypub.activity.sent", eventAttributes);
   } finally {
     federationMetrics.recordDelivery(
       inbox,

packages/fedify/src/otel/exporter.test.ts

@@ -99,11 +99,19 @@ function createActivitySentEvent(options: {
   activityJson?: string;
   inboxUrl: string;
   activityId?: string;
+  activityType?: string;
+  actorId?: string;
 }): TimedEvent {
   const attributes: Attributes = {
     "activitypub.inbox.url": options.inboxUrl,
     "activitypub.activity.id": options.activityId ?? "",
   };
+  if (options.activityType != null) {
+    attributes["activitypub.activity.type"] = options.activityType;
+  }
+  if (options.actorId != null) {
+    attributes["activitypub.actor.id"] = options.actorId;
+  }
   if (options.activityJson != null) {
     attributes["activitypub.activity.json"] = options.activityJson;
   }
@@ -180,6 +188,8 @@ test("FedifySpanExporter", async (t) => {
       const spanId = "span012";
       const inboxUrl = "https://example.com/users/alice/inbox";
       const activityId = "https://myserver.com/activities/789";
+      const activityType = "https://www.w3.org/ns/activitystreams#Accept";
+      const actorId = "https://myserver.com/users/bob";
 
       const span = createMockSpan({
         traceId,
@@ -189,6 +199,8 @@ test("FedifySpanExporter", async (t) => {
           createActivitySentEvent({
             inboxUrl,
             activityId,
+            activityType,
+            actorId,
           }),
         ],
       });
@@ -205,8 +217,9 @@ test("FedifySpanExporter", async (t) => {
       assertEquals(activities[0].traceId, traceId);
       assertEquals(activities[0].spanId, spanId);
       assertEquals(activities[0].direction, "outbound");
-      assertEquals(activities[0].activityType, "Unknown");
+      assertEquals(activities[0].activityType, activityType);
       assertEquals(activities[0].activityId, activityId);
+      assertEquals(activities[0].actorId, actorId);
       assertEquals(activities[0].activityJson, undefined);
       assertEquals(activities[0].inboxUrl, inboxUrl);
     },

packages/fedify/src/otel/exporter.ts

@@ -432,18 +432,25 @@ export class FedifySpanExporter implements SpanExporter {
 
     const inboxUrl = attrs["activitypub.inbox.url"];
     const explicitActivityId = attrs["activitypub.activity.id"];
+    const explicitActivityType = attrs["activitypub.activity.type"];
+    const explicitActorId = attrs["activitypub.actor.id"];
 
     return {
       traceId,
       spanId,
       parentSpanId,
       direction: "outbound",
-      activityType,
+      activityType:
+        typeof explicitActivityType === "string" && explicitActivityType !== ""
+          ? explicitActivityType
+          : activityType,
       activityId: activityId ??
         (typeof explicitActivityId === "string" && explicitActivityId !== ""
           ? explicitActivityId
           : undefined),
-      actorId,
+      actorId: typeof explicitActorId === "string" && explicitActorId !== ""
+        ? explicitActorId
+        : actorId,
       ...(typeof activityJson === "string" ? { activityJson } : {}),
       timestamp: new Date(
         event.time[0] * 1000 + event.time[1] / 1e6,