Improve cloud aggregation for different URLs (#1220)

stats/cloud: improve cloud aggregation for different URLs

For cloud output, we currently don't aggregate HTTP metrics with
different url tag, but with the same name tag.

This PR improves aggregation by setting url tag to be the same as name
tag. It's not ideal, but seems like the least bad option in term of UX.

Fixes #1166

stats/cloud/collector.go

@@ -250,6 +250,24 @@ func (c *Collector) Run(ctx context.Context) {
 	}
 }
 
+func useCloudTags(source *httpext.Trail) *httpext.Trail {
+	name, nameExist := source.Tags.Get("name")
+	url, urlExist := source.Tags.Get("url")
+	if !nameExist || !urlExist || name == url {
+		return source
+	}
+
+	newTags := source.Tags.CloneTags()
+	newTags["url"] = name
+
+	dest := new(httpext.Trail)
+	*dest = *source
+	dest.Tags = stats.IntoSampleTags(&newTags)
+	dest.Samples = nil
+
+	return dest
+}
+
 // Collect receives a set of samples. This method is never called concurrently, and only while
 // the context for Run() is valid, but should defer as much work as possible to Run().
 func (c *Collector) Collect(sampleContainers []stats.SampleContainer) {
@@ -269,6 +287,7 @@ func (c *Collector) Collect(sampleContainers []stats.SampleContainer) {
 	for _, sampleContainer := range sampleContainers {
 		switch sc := sampleContainer.(type) {
 		case *httpext.Trail:
+			sc = useCloudTags(sc)
 			// Check if aggregation is enabled,
 			if c.config.AggregationPeriod.Duration > 0 {
 				newHTTPTrails = append(newHTTPTrails, sc)

stats/cloud/collector_test.go

@@ -47,6 +47,26 @@ import (
 	"github.com/loadimpact/k6/stats"
 )
 
+func tagEqual(expected, got *stats.SampleTags) bool {
+	expectedMap := expected.CloneTags()
+	gotMap := got.CloneTags()
+
+	if len(expectedMap) != len(gotMap) {
+		return false
+	}
+
+	for k, v := range gotMap {
+		if k == "url" {
+			if expectedMap["name"] != v {
+				return false
+			}
+		} else if expectedMap[k] != v {
+			return false
+		}
+	}
+	return true
+}
+
 func getSampleChecker(t *testing.T, expSamples <-chan []Sample) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		body, err := ioutil.ReadAll(r.Body)
@@ -84,7 +104,7 @@ func getSampleChecker(t *testing.T, expSamples <-chan []Sample) http.HandlerFunc
 			case *SampleDataMap:
 				receivedData, ok := receivedSample.Data.(*SampleDataMap)
 				assert.True(t, ok)
-				assert.True(t, expData.Tags.IsEqual(receivedData.Tags))
+				assert.True(t, tagEqual(expData.Tags, receivedData.Tags))
 				assert.True(t, expData.Time.Equal(receivedData.Time))
 				assert.Equal(t, expData.Type, receivedData.Type)
 				assert.Equal(t, expData.Values, receivedData.Values)
@@ -170,7 +190,11 @@ func TestCloudCollector(t *testing.T) {
 	assert.Equal(t, types.Duration(5*time.Millisecond), collector.config.AggregationWaitPeriod.Duration)
 
 	now := time.Now()
-	tags := stats.IntoSampleTags(&map[string]string{"test": "mest", "a": "b"})
+	tagMap := map[string]string{"test": "mest", "a": "b", "name": "name", "url": "url"}
+	tags := stats.IntoSampleTags(&tagMap)
+	expectedTagMap := tags.CloneTags()
+	expectedTagMap["url"], _ = tags.Get("name")
+	expectedTags := stats.IntoSampleTags(&expectedTagMap)
 
 	expSamples := make(chan []Sample)
 	tb.Mux.HandleFunc(fmt.Sprintf("/v1/metrics/%s", collector.referenceID), getSampleChecker(t, expSamples))
@@ -243,7 +267,7 @@ func TestCloudCollector(t *testing.T) {
 			Data: func(data interface{}) {
 				aggrData, ok := data.(*SampleDataAggregatedHTTPReqs)
 				assert.True(t, ok)
-				assert.True(t, aggrData.Tags.IsEqual(tags))
+				assert.True(t, aggrData.Tags.IsEqual(expectedTags))
 				assert.Equal(t, collector.config.AggregationMinSamples.Int64, int64(aggrData.Count))
 				assert.Equal(t, "aggregated_trend", aggrData.Type)
 				assert.InDelta(t, now.UnixNano(), time.Time(aggrData.Time).UnixNano(), float64(collector.config.AggregationPeriod.Duration))