feat(discover): Support sum function while querying metrics in discover (#35576)

Adds support to sum() support to metrics queries in discover

Author: edwardgou-sentry

src/sentry/search/events/datasets/metrics.py

@@ -238,6 +238,21 @@ def function_converter(self) -> Mapping[str, fields.MetricsFunction]:
                         alias,
                     ),
                 ),
+                fields.MetricsFunction(
+                    "sum",
+                    required_args=[
+                        fields.MetricArg("column"),
+                    ],
+                    calculated_args=[resolve_metric_id],
+                    snql_distribution=lambda args, alias: Function(
+                        "sumIf",
+                        [
+                            Column("value"),
+                            Function("equals", [Column("metric_id"), args["metric_id"]]),
+                        ],
+                        alias,
+                    ),
+                ),
                 fields.MetricsFunction(
                     "percentile",
                     required_args=[

tests/snuba/api/endpoints/test_organization_events_stats.py

@@ -1152,6 +1152,26 @@ def test_explicit_not_mep(self):
         assert response.status_code == 200, response.content
         return not response.data["isMetricsData"]
 
+    def test_sum_transaction_duration(self):
+        self.store_metric(123, timestamp=self.day_ago + timedelta(minutes=30))
+        self.store_metric(456, timestamp=self.day_ago + timedelta(hours=1, minutes=30))
+        self.store_metric(789, timestamp=self.day_ago + timedelta(hours=1, minutes=30))
+        response = self.do_request(
+            data={
+                "start": iso_format(self.day_ago),
+                "end": iso_format(self.day_ago + timedelta(hours=2)),
+                "interval": "1h",
+                "yAxis": "sum(transaction.duration)",
+                "metricsEnhanced": "1",
+            },
+        )
+        assert response.status_code == 200, response.content
+        assert response.data["isMetricsData"]
+        assert [attrs for time, attrs in response.data["data"]] == [
+            [{"count": 123}],
+            [{"count": 1245}],
+        ]
+
 
 class OrganizationEventsStatsTopNEvents(APITestCase, SnubaTestCase):
     def setUp(self):

tests/snuba/api/endpoints/test_organization_events_v2.py

@@ -11961,3 +11961,41 @@ def test_count_unique_user_returns_zero(self):
         assert data[1]["transaction"] == "bar_transaction"
         assert data[1]["count_unique(user)"] == 0
         assert meta["isMetricsData"]
+
+    def test_sum_transaction_duration(self):
+        self.store_metric(
+            50,
+            tags={"transaction": "foo_transaction"},
+            timestamp=self.min_ago,
+        )
+        self.store_metric(
+            100,
+            tags={"transaction": "foo_transaction"},
+            timestamp=self.min_ago,
+        )
+        self.store_metric(
+            150,
+            tags={"transaction": "foo_transaction"},
+            timestamp=self.min_ago,
+        )
+
+        query = {
+            "project": [self.project.id],
+            "orderby": "sum(transaction.duration)",
+            "field": [
+                "transaction",
+                "sum(transaction.duration)",
+            ],
+            "dataset": "metricsEnhanced",
+            "per_page": 50,
+        }
+
+        response = self.do_request(query)
+        assert response.status_code == 200, response.content
+        assert len(response.data["data"]) == 1
+        data = response.data["data"]
+        meta = response.data["meta"]
+
+        assert data[0]["transaction"] == "foo_transaction"
+        assert data[0]["sum(transaction.duration)"] == 300
+        assert meta["isMetricsData"]