Align delivery telemetry attributes

Record delivery success on delivery duration metrics so successful and
failed attempts can be separated in histograms, and remove the stale sent
activity JSON attribute from the OpenTelemetry docs.

#755 (comment)
#755 (comment)

Assisted-by: gpt-5.5

Author: dahlia

docs/manual/opentelemetry.md

@@ -263,7 +263,6 @@ Each span event includes attributes with detailed information:
 
 **`activitypub.activity.sent` event attributes:**
 
- -  `activitypub.activity.json`: The complete activity JSON being sent
  -  `activitypub.inbox.url`: The inbox URL where the activity was delivered
  -  `activitypub.activity.id`: The activity ID
 
@@ -307,7 +306,7 @@ Fedify records the following OpenTelemetry metrics:
 :   `activitypub.remote.host` and `http.response.status_code`.
 
 `activitypub.delivery.duration`
-:   `activitypub.remote.host`.
+:   `activitypub.remote.host` and `activitypub.delivery.success`.
 
 `activitypub.inbox.processing_duration`
 :   `activitypub.activity.type`.

packages/fedify/src/federation/metrics.ts

@@ -66,6 +66,7 @@ class FederationMetrics {
     this.deliverySent.add(1, deliveryAttributes);
     this.deliveryDuration.record(durationMs, {
       "activitypub.remote.host": getRemoteHost(inbox),
+      "activitypub.delivery.success": success,
     });
   }
 

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

@@ -554,6 +554,10 @@ test("sendActivity() records OpenTelemetry delivery metrics", async (t) => {
       durations[0].attributes["activitypub.remote.host"],
       "metrics.example",
     );
+    assertEquals(
+      durations[0].attributes["activitypub.delivery.success"],
+      true,
+    );
 
     recorder.clear();
     fetchMock.hardReset();
@@ -607,6 +611,10 @@ test("sendActivity() records OpenTelemetry delivery metrics", async (t) => {
       durations[0].attributes["activitypub.remote.host"],
       "metrics.example",
     );
+    assertEquals(
+      durations[0].attributes["activitypub.delivery.success"],
+      false,
+    );
 
     recorder.clear();
     fetchMock.hardReset();