fix(charts): prevent displaying stats before requests are made

locust/static/locust.js

@@ -16,9 +16,11 @@ function appearStopped() {
 
 $("#box_stop a.stop-button").click(function(event) {
     event.preventDefault();
-    $.get($(this).attr("href"));
+    $.get($(this).attr("href")).done(() => {
+        markerFlags.stop = true;
+    });
     $("body").attr("class", "stopped");
-    appearStopped()
+    appearStopped();
 });
 
 $("#box_stop a.reset-button").click(function(event) {
@@ -79,6 +81,11 @@ $('#swarm_form').submit(function(event) {
         function(response) {
             if (response.success) {
                 setHostName(response.host);
+
+                // only mark run starts if at least 1 run has been reported
+                if (stats_history["time"].length > 0) {
+                    markerFlags.start = true;
+                }
             }
         }
     );
@@ -174,30 +181,39 @@ $("#workers .stats_label").click(function(event) {
     renderWorkerTable(window.report);
 });
 
+function createMarkLine() {
+    return {
+        symbol: "none",
+        label: {
+            formatter: params => `Run #${params.dataIndex + 1}`
+        },
+        lineStyle: {color: "#5b6f66"},
+        data: stats_history["markers"],
+    }
+}
+
 function update_stats_charts(){
     if(stats_history["time"].length > 0){
         rpsChart.chart.setOption({
             xAxis: {data: stats_history["time"]},
             series: [
-                {data: stats_history["current_rps"]},
+                {data: stats_history["current_rps"], markLine: createMarkLine()},
                 {data: stats_history["current_fail_per_sec"]},
             ]
         });
 
         responseTimeChart.chart.setOption({
             xAxis: {data: stats_history["time"]},
             series: [
-                {data: stats_history["response_time_percentile_50"]},
+                {data: stats_history["response_time_percentile_50"], markLine: createMarkLine()},
                 {data: stats_history["response_time_percentile_95"]},
             ]
         });
 
         usersChart.chart.setOption({
-            xAxis: {
-                data: stats_history["time"]
-            },
+            xAxis: {data: stats_history["time"]},
             series: [
-                {data: stats_history["user_count"]},
+                {data: stats_history["user_count"], markLine: createMarkLine()},
             ]
         });
     }
@@ -210,27 +226,70 @@ var usersChart = new LocustLineChart($(".charts-container"), "Number of Users",
 charts.push(rpsChart, responseTimeChart, usersChart);
 update_stats_charts()
 
+const markerFlags = {
+    start: false,
+    stop: false,
+}
+
 function updateStats() {
     $.get('./stats/requests', function (report) {
         window.report = report;
         try{
             renderTable(report);
             renderWorkerTable(report);
 
-            if (report.state !== "stopped"){
-                // get total stats row
-                var total = report.stats[report.stats.length-1];
-                // update charts
-                stats_history["time"].push(new Date().toLocaleTimeString());
-                stats_history["user_count"].push({"value": report.user_count});
-                stats_history["current_rps"].push({"value": total.current_rps, "users": report.user_count});
-                stats_history["current_fail_per_sec"].push({"value": total.current_fail_per_sec, "users": report.user_count});
-                stats_history["response_time_percentile_50"].push({"value": report.current_response_time_percentile_50, "users": report.user_count});
-                stats_history["response_time_percentile_95"].push({"value": report.current_response_time_percentile_95, "users": report.user_count});
-                update_stats_charts()
-            } else {
+            const time = new Date().toLocaleTimeString();
+
+            if (report.state === "stopped") {
+                if (markerFlags.stop) {
+                    markerFlags.stop = false;
+
+                    // placeholders to show a skip in the lines between test runs
+                    stats_history["time"].push(time);
+                    stats_history["user_count"].push({"value": null});
+                    stats_history["current_rps"].push({"value": null});
+                    stats_history["current_fail_per_sec"].push({"value": null});
+                    stats_history["response_time_percentile_50"].push({"value": null});
+                    stats_history["response_time_percentile_95"].push({"value": null});
+                }
+
+                // update stats chart to ensure the stop spacing appears as part 
+                // of the update loop, otherwise we will "jump" 2 plots on the next run 
+                update_stats_charts();
+
                 appearStopped();
+                return;
+            }
+
+            // add markers between test runs, based on a new run being started
+            if (stats_history["time"].length > 0 && markerFlags.start) {
+                markerFlags.start = false;
+
+                // mark the first run when we start the second run
+                if (stats_history["markers"].length === 0) {
+                    stats_history["markers"].push({xAxis: stats_history["time"][0]});
+                }
+
+                stats_history["markers"].push({xAxis: time});
             }
+
+            // get total stats row
+            var total = report.stats[report.stats.length-1];
+
+            // ignore stats without requests
+            if (total.num_requests < 1) {
+                return;
+            }
+
+            // update charts
+            stats_history["time"].push(time);
+            stats_history["user_count"].push({"value": report.user_count});
+            stats_history["current_rps"].push({"value": total.current_rps, "users": report.user_count});
+            stats_history["current_fail_per_sec"].push({"value": total.current_fail_per_sec, "users": report.user_count});
+            stats_history["response_time_percentile_50"].push({"value": report.current_response_time_percentile_50, "users": report.user_count});
+            stats_history["response_time_percentile_95"].push({"value": report.current_response_time_percentile_95, "users": report.user_count});
+            update_stats_charts();
+
         } catch(i){
             console.debug(i);
         }

locust/stats.py

@@ -579,7 +579,7 @@ def get_current_response_time_percentile(self, percent):
                 break
 
         if cached:
-            # If we fond an acceptable cached response times, we'll calculate a new response
+            # If we found an acceptable cached response times, we'll calculate a new response
             # times dict of the last 10 seconds (approximately) by diffing it with the current
             # total response times. Then we'll use that to calculate a response time percentile
             # for that timeframe
@@ -588,6 +588,8 @@ def get_current_response_time_percentile(self, percent):
                 self.num_requests - cached.num_requests,
                 percent,
             )
+        # if time was not in response times cache window
+        return None
 
     def percentile(self):
         if not self.num_requests:

locust/templates/stats_data.html

@@ -6,4 +6,5 @@
     "current_fail_per_sec": {{ current_fail_per_sec_data | tojson }},
     "response_time_percentile_50": {{ response_time_percentile_50_data | tojson }},
     "response_time_percentile_95": {{ response_time_percentile_95_data | tojson }},
+    "markers": [],
 };

locust/test/test_stats.py

@@ -580,6 +580,12 @@ def test_get_current_response_time_percentile(self):
 
         self.assertEqual(95, s.get_current_response_time_percentile(0.95))
 
+    def test_get_current_response_time_percentile_outside_cache_window(self):
+        s = StatsEntry(self.stats, "/", "GET", use_response_times_cache=True)
+        # an empty response times cache, current time will not be in this cache
+        s.response_times_cache = {}
+        self.assertEqual(None, s.get_current_response_time_percentile(0.95))
+
     def test_diff_response_times_dicts(self):
         self.assertEqual(
             {1: 5, 6: 8},

locust/web.py

@@ -426,7 +426,7 @@ def update_template_args(self):
             "user_count": self.environment.runner.user_count,
             "version": version,
             "host": host,
-            "history": stats.history,
+            "history": stats.history if stats.num_requests > 0 else {},
             "override_host_warning": override_host_warning,
             "num_users": options and options.num_users,
             "spawn_rate": options and options.spawn_rate,