Fix Regression in Full History CSV Percentiles (#1873)

* full history CSV should use current percentile

Fixes a regression that I believe was introduced in August 18th, 2020. Before then, the full history CSV used current percentiles (starting from December 3rd, 2019).

* Sanity Check

* Debugging logs...

* Remove Sanity Checks from UI

* Remove sanity/debug print statements

* Revert <br> that I accidentally left in.

* Formatting change to appease tox.

* Update unit test to demonstrate fix and prevent future regressions.

locust/stats.py

@@ -842,12 +842,13 @@ def __init__(self, environment, percentiles_to_report):
             "Nodes",
         ]
 
-    def _percentile_fields(self, stats_entry):
-        return (
-            [int(stats_entry.get_response_time_percentile(x) or 0) for x in self.percentiles_to_report]
-            if stats_entry.num_requests
-            else self.percentiles_na
-        )
+    def _percentile_fields(self, stats_entry, use_current=False):
+        if not stats_entry.num_requests:
+            return self.percentiles_na
+        elif use_current:
+            return [int(stats_entry.get_current_response_time_percentile(x) or 0) for x in self.percentiles_to_report]
+        else:
+            return [int(stats_entry.get_response_time_percentile(x) or 0) for x in self.percentiles_to_report]
 
     def requests_csv(self, csv_writer):
         """Write requests csv with header and data rows."""
@@ -1012,7 +1013,7 @@ def _stats_history_data_rows(self, csv_writer, now):
                         f"{stats_entry.current_rps:2f}",
                         f"{stats_entry.current_fail_per_sec:2f}",
                     ),
-                    self._percentile_fields(stats_entry),
+                    self._percentile_fields(stats_entry, use_current=self.full_history),
                     (
                         stats_entry.num_requests,
                         stats_entry.num_failures,

locust/test/test_stats.py

@@ -377,8 +377,18 @@ def test_csv_stats_writer_full_history(self):
         stats_writer = StatsCSVFileWriter(
             self.environment, PERCENTILES_TO_REPORT, self.STATS_BASE_NAME, full_history=True
         )
-        self.runner.stats.log_request("GET", "/", 10, content_length=666)
+
+        for i in range(10):
+            self.runner.stats.log_request("GET", "/", 100, content_length=666)
+
         greenlet = gevent.spawn(stats_writer)
+        gevent.sleep(10)
+
+        for i in range(10):
+            self.runner.stats.log_request("GET", "/", 10, content_length=666)
+
+        gevent.sleep(5)
+
         gevent.sleep(_TEST_CSV_STATS_INTERVAL_WAIT_SEC)
         gevent.kill(greenlet)
         stats_writer.close_files()
@@ -392,11 +402,26 @@ def test_csv_stats_writer_full_history(self):
             reader = csv.DictReader(f)
             rows = [r for r in reader]
 
-        self.assertEqual(4, len(rows))
+        self.assertGreaterEqual(len(rows), 130)
+
         self.assertEqual("/", rows[0]["Name"])
         self.assertEqual("Aggregated", rows[1]["Name"])
         self.assertEqual("/", rows[2]["Name"])
         self.assertEqual("Aggregated", rows[3]["Name"])
+        self.assertEqual("20", rows[-1]["Total Request Count"])
+
+        saw100 = False
+        saw10 = False
+
+        for row in rows:
+            if not saw100 and row["95%"] == "100":
+                saw100 = True
+            elif saw100 and row["95%"] == "10":
+                saw10 = True
+                break
+
+        self.assertTrue(saw100, "Never saw 95th percentile increase to 100")
+        self.assertTrue(saw10, "Never saw 95th percentile decrease to 10")
 
     def test_csv_stats_on_master_from_aggregated_stats(self):
         # Failing test for: https://github.com/locustio/locust/issues/1315