From 10706ecdc16805f3c4069fe724db96f210a25046 Mon Sep 17 00:00:00 2001
From: Vikram Raman <vikram@wavefront.com>
Date: Tue, 19 Feb 2019 16:20:50 -0800
Subject: [PATCH] handle multiple data points

---
 Makefile                   | 11 ++++++++---
 pkg/client/api.go          |  6 +++---
 pkg/provider/provider.go   |  5 +++--
 pkg/provider/translator.go | 32 ++++++++++++++++++--------------
 4 files changed, 32 insertions(+), 22 deletions(-)

diff --git a/Makefile b/Makefile
index 472e5d2..f5f82f5 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,10 @@ OUT_DIR?=./_output
 TEMP_DIR:=$(shell mktemp -d)
 DOCKER_REPO=wavefronthq
 DOCKER_IMAGE=wavefront-hpa-adapter
-VERSION=0.9
+VERSION=0.9.1
+
+# for testing, the built image will also be tagged with this name
+OVERRIDE_IMAGE_NAME?=vikramraman/wavefront-adapter
 
 .PHONY: all test verify-gofmt gofmt verify
 
@@ -40,9 +43,11 @@ container: build-linux
 	cp deploy/Dockerfile $(TEMP_DIR)
 	cp $(OUT_DIR)/$(ARCH)/wavefront-adapter-linux $(TEMP_DIR)/wavefront-adapter
 	cd $(TEMP_DIR)
-	docker build -t $(DOCKER_REPO)/$(DOCKER_IMAGE)-$(ARCH):$(VERSION) $(TEMP_DIR)
-	docker tag $(DOCKER_REPO)/$(DOCKER_IMAGE)-$(ARCH):$(VERSION) $(DOCKER_REPO)/$(DOCKER_IMAGE):latest
+	docker build -t $(DOCKER_REPO)/$(DOCKER_IMAGE):$(VERSION) $(TEMP_DIR)
 	rm -rf $(TEMP_DIR)
+ifneq ($(OVERRIDE_IMAGE_NAME),)
+	docker tag $(DOCKER_REPO)/$(DOCKER_IMAGE):$(VERSION) $(OVERRIDE_IMAGE_NAME)
+endif
 
 clean:
 	rm -rf $(OUT_DIR)
diff --git a/pkg/client/api.go b/pkg/client/api.go
index 68e99fc..9d81d22 100644
--- a/pkg/client/api.go
+++ b/pkg/client/api.go
@@ -95,8 +95,8 @@ func (w DefaultWavefrontClient) ListMetrics(prefix string) ([]string, error) {
 	return result.Metrics, nil
 }
 
-func (w DefaultWavefrontClient) Query(ts int64, query string) (QueryResult, error) {
-	glog.V(4).Infof("DEBUG:---WavefrontClient.Query: ts=%s, query=%s", ts, query)
+func (w DefaultWavefrontClient) Query(start int64, query string) (QueryResult, error) {
+	glog.V(4).Infof("DEBUG:---WavefrontClient.Query: start=%s, query=%s", start, query)
 	if query == "" {
 		return QueryResult{}, &Error{
 			Type: ErrBadData,
@@ -106,7 +106,7 @@ func (w DefaultWavefrontClient) Query(ts int64, query string) (QueryResult, erro
 
 	vals := url.Values{}
 	vals.Set(queryKey, query)
-	vals.Set(startTime, strconv.FormatInt(ts, 10))
+	vals.Set(startTime, strconv.FormatInt(start, 10))
 	vals.Set(granularity, "m")
 
 	resp, err := w.Do("GET", chartEndpoint, vals)
diff --git a/pkg/provider/provider.go b/pkg/provider/provider.go
index ab9cad0..3f04210 100644
--- a/pkg/provider/provider.go
+++ b/pkg/provider/provider.go
@@ -73,8 +73,9 @@ func (p *wavefrontProvider) query(info provider.CustomMetricInfo, namespace stri
 }
 
 func (p *wavefrontProvider) doQuery(query string) (wave.QueryResult, error) {
-	now := time.Now().Unix()
-	queryResult, err := p.waveClient.Query(now, query)
+	now := time.Now()
+	start := now.Add(time.Duration(-30) * time.Second)
+	queryResult, err := p.waveClient.Query(start.Unix(), query)
 	if err != nil {
 		glog.Errorf("unable to fetch metrics from wavefront: %v", err)
 		// don't leak implementation details to the user
diff --git a/pkg/provider/translator.go b/pkg/provider/translator.go
index ec70dfa..f375fa1 100644
--- a/pkg/provider/translator.go
+++ b/pkg/provider/translator.go
@@ -101,25 +101,29 @@ func (t WavefrontTranslator) ExternalMetricsFor(metricNames []string) []provider
 }
 
 func (t WavefrontTranslator) ExternalValuesFor(queryResult wave.QueryResult, name string) (*external_metrics.ExternalMetricValueList, error) {
-	matchingMetrics := []external_metrics.ExternalMetricValue{}
+	var matchingMetrics []external_metrics.ExternalMetricValue
 	for _, timeseries := range queryResult.Timeseries {
-		if len(timeseries.Data) == 0 {
+		length := len(timeseries.Data)
+		if length == 0 {
 			return nil, fmt.Errorf("no data for external metric: %s", name)
 		}
 
-		for _, metric := range timeseries.Data {
-			value, err := trimFloat(metric[1])
-			if err != nil {
-				glog.Errorf("error converting external metric: %s value: %f", name, metric[1])
-				continue
-			}
-			metricValue := external_metrics.ExternalMetricValue{
-				MetricName: name,
-				Value:      *resource.NewMilliQuantity(int64(1000*value), resource.DecimalSI),
-				Timestamp:  metav1.Now(),
-			}
-			matchingMetrics = append(matchingMetrics, metricValue)
+		// use the last data point
+		point := timeseries.Data[length-1]
+		if len(point) != 2 {
+			return nil, fmt.Errorf("invalid data point for external metric: %s", name)
+		}
+		value, err := trimFloat(point[1])
+		if err != nil {
+			glog.Errorf("error converting external metric: %s value: %f", name, point[1])
+			continue
+		}
+		metricValue := external_metrics.ExternalMetricValue{
+			MetricName: name,
+			Value:      *resource.NewMilliQuantity(int64(1000*value), resource.DecimalSI),
+			Timestamp:  metav1.Now(),
 		}
+		matchingMetrics = append(matchingMetrics, metricValue)
 	}
 	return &external_metrics.ExternalMetricValueList{
 		Items: matchingMetrics,