fix: Default to 0 if nothing to sum in batch exports app metrics (#21851

)

* fix: Default to 0 if nothing to sum

* test: Add test case

posthog/api/app_metrics.py

@@ -118,8 +118,12 @@ def get_batch_export_runs_app_metrics_queryset(self, batch_export_id: str):
             .annotate(dates=TruncDay("last_updated_at"))
             .values("dates")
             .annotate(
-                successes=Sum(Coalesce("records_total_count", 0), filter=Q(status=BatchExportRun.Status.COMPLETED)),
-                failures=Sum(Coalesce("records_total_count", 0), filter=~Q(status=BatchExportRun.Status.COMPLETED)),
+                successes=Sum(
+                    Coalesce("records_total_count", 0), filter=Q(status=BatchExportRun.Status.COMPLETED), default=0
+                ),
+                failures=Sum(
+                    Coalesce("records_total_count", 0), filter=~Q(status=BatchExportRun.Status.COMPLETED), default=0
+                ),
             )
             .order_by("dates")
             .all()

posthog/api/test/test_app_metrics.py

@@ -156,6 +156,75 @@ def test_retrieve_batch_export_runs_app_metrics(self):
                 },
             )
 
+    def test_retrieve_batch_export_runs_app_metrics_defaults_to_zero(self):
+        """Test batch export metrics returned by app metrics endpoint."""
+        destination_data = {
+            "type": "S3",
+            "config": {
+                "bucket_name": "my-production-s3-bucket",
+                "region": "us-east-1",
+                "prefix": "posthog-events/",
+                "aws_access_key_id": "abc123",
+                "aws_secret_access_key": "secret",
+            },
+        }
+
+        batch_export_data = {
+            "name": "my-production-s3-bucket-destination",
+            "destination": destination_data,
+            "interval": "hour",
+        }
+
+        temporal = sync_connect()
+        now = dt.datetime(2021, 12, 5, 13, 23, 0, tzinfo=dt.timezone.utc)
+
+        with start_test_worker(temporal):
+            response = create_batch_export_ok(
+                self.client,
+                self.team.pk,
+                json.dumps(batch_export_data),
+            )
+            batch_export_id = response["id"]
+
+            for days_ago in range(0, 7):
+                last_updated_at = now - dt.timedelta(days=days_ago)
+
+                with freeze_time(last_updated_at):
+                    # Since 'last_updated_at' uses 'auto_now', passing the argument is ignored.
+                    # We have to re-freeze time to get each run created on a single date.
+                    BatchExportRun.objects.create(
+                        batch_export_id=batch_export_id,
+                        data_interval_end=last_updated_at,
+                        data_interval_start=last_updated_at - dt.timedelta(hours=1),
+                        status=BatchExportRun.Status.COMPLETED,
+                        records_completed=1,
+                        records_total_count=1,
+                    )
+
+            response = self.client.get(f"/api/projects/@current/app_metrics/{batch_export_id}?date_from=-7d")
+            self.assertEqual(response.status_code, status.HTTP_200_OK)
+            self.assertEqual(
+                response.json(),
+                {
+                    "metrics": {
+                        "dates": [
+                            "2021-11-29",
+                            "2021-11-30",
+                            "2021-12-01",
+                            "2021-12-02",
+                            "2021-12-03",
+                            "2021-12-04",
+                            "2021-12-05",
+                        ],
+                        "successes": [1, 1, 1, 1, 1, 1, 1],
+                        "successes_on_retry": [0, 0, 0, 0, 0, 0, 0],
+                        "failures": [0, 0, 0, 0, 0, 0, 0],
+                        "totals": {"successes": 7, "successes_on_retry": 0, "failures": 0},
+                    },
+                    "errors": None,
+                },
+            )
+
     def test_list_historical_exports(self):
         self._create_activity_log(
             activity="job_triggered",