elasticsearch: support bucket script pipeline aggregations

pkg/tsdb/elasticsearch/response_parser.go

@@ -260,6 +260,7 @@ func (rp *responseParser) processMetrics(esAgg *simplejson.Json, target *Query,
 
 			newSeries.Tags["metric"] = metric.Type
 			newSeries.Tags["field"] = metric.Field
+			newSeries.Tags["metricId"] = metric.ID
 			for _, v := range esAgg.Get("buckets").MustArray() {
 				bucket := simplejson.NewFromAny(v)
 				key := castToNullFloat(bucket.Get("key"))
@@ -459,20 +460,42 @@ func (rp *responseParser) getSeriesName(series *tsdb.TimeSeries, target *Query,
 	}
 	// todo, if field and pipelineAgg
 	if field != "" && isPipelineAgg(metricType) {
-		found := false
-		for _, metric := range target.Metrics {
-			if metric.ID == field {
-				metricName += " " + describeMetric(metric.Type, field)
-				found = true
+		if isPipelineAggWithMultipleBucketPaths(metricType) {
+			metricID := ""
+			if v, ok := series.Tags["metricId"]; ok {
+				metricID = v
+			}
+
+			for _, metric := range target.Metrics {
+				if metric.ID == metricID {
+					metricName = metric.Settings.Get("script").MustString()
+					for name, pipelineAgg := range metric.PipelineVariables {
+						for _, m := range target.Metrics {
+							if m.ID == pipelineAgg {
+								metricName = strings.Replace(metricName, "params."+name, describeMetric(m.Type, m.Field), -1)
+							}
+						}
+					}
+				}
+			}
+		} else {
+			found := false
+			for _, metric := range target.Metrics {
+				if metric.ID == field {
+					metricName += " " + describeMetric(metric.Type, field)
+					found = true
+				}
+			}
+			if !found {
+				metricName = "Unset"
 			}
-		}
-		if !found {
-			metricName = "Unset"
 		}
 	} else if field != "" {
 		metricName += " " + field
 	}
 
+	delete(series.Tags, "metricId")
+
 	if len(series.Tags) == 0 {
 		return metricName
 	}