Improve logging of prometheus-to-sd.

Add component names to logs, replace some warning log messages with
info and update verbosity level for some of them.

prometheus-to-sd/main.go

@@ -133,6 +133,7 @@ func readAndPushDataToStackdriver(stackdriverService *v3.Service, gceConf *confi
 			metricDescriptorCache.Refresh()
 			if useWhitelistedMetricsAutodiscovery {
 				sourceConfig.UpdateWhitelistedMetrics(metricDescriptorCache.GetMetricNames())
+				glog.V(2).Infof("Autodiscovered whitelisted metrics for component %v: %v", commonConfig.ComponentName, sourceConfig.Whitelisted)
 			}
 			signal = time.After(*metricDescriptorsResolution)
 		default:
@@ -143,7 +144,7 @@ func readAndPushDataToStackdriver(stackdriverService *v3.Service, gceConf *confi
 		}
 		metrics, err := translator.GetPrometheusMetrics(sourceConfig.Host, sourceConfig.Port)
 		if err != nil {
-			glog.Warningf("Error while getting Prometheus metrics %v", err)
+			glog.V(2).Infof("Error while getting Prometheus metrics %v for component %v", err, sourceConfig.Component)
 			continue
 		}
 		if *omitComponentName {
@@ -153,6 +154,6 @@ func readAndPushDataToStackdriver(stackdriverService *v3.Service, gceConf *confi
 			metricDescriptorCache.UpdateMetricDescriptors(metrics, sourceConfig.Whitelisted)
 		}
 		ts := translator.TranslatePrometheusToStackdriver(commonConfig, sourceConfig.Whitelisted, metrics, metricDescriptorCache)
-		translator.SendToStackdriver(stackdriverService, gceConf, ts)
+		translator.SendToStackdriver(stackdriverService, commonConfig, ts)
 	}
 }

prometheus-to-sd/translator/metric_descriptor_cache.go

@@ -110,7 +110,7 @@ func (cache *MetricDescriptorCache) updateMetricDescriptorIfStale(metricFamily *
 func (cache *MetricDescriptorCache) getMetricDescriptor(metric string) *v3.MetricDescriptor {
 	value, ok := cache.descriptors[metric]
 	if !ok {
-		glog.Warningf("Metric %s was not found in the cache.", metric)
+		glog.V(4).Infof("Metric %s was not found in the cache for component %v", metric, cache.component)
 	}
 	return value
 }

prometheus-to-sd/translator/stackdriver.go

@@ -33,13 +33,13 @@ const (
 )
 
 // SendToStackdriver sends http request to Stackdriver to create the given timeserieses.
-func SendToStackdriver(service *v3.Service, config *config.GceConfig, ts []*v3.TimeSeries) {
+func SendToStackdriver(service *v3.Service, config *config.CommonConfig, ts []*v3.TimeSeries) {
 	if len(ts) == 0 {
-		glog.Warningf("No metrics to send to Stackdriver")
+		glog.V(3).Infof("No metrics to send to Stackdriver for component %v", config.ComponentName)
 		return
 	}
 
-	proj := createProjectName(config)
+	proj := createProjectName(config.GceConfig)
 
 	var wg sync.WaitGroup
 	var failedTs uint32
@@ -60,7 +60,7 @@ func SendToStackdriver(service *v3.Service, config *config.GceConfig, ts []*v3.T
 		}(i, end)
 	}
 	wg.Wait()
-	glog.V(4).Infof("Successfully sent %v timeserieses to Stackdriver", uint32(len(ts))-failedTs)
+	glog.V(4).Infof("Successfully sent %v timeserieses to Stackdriver for component %v", uint32(len(ts))-failedTs, config.ComponentName)
 }
 
 func getMetricDescriptors(service *v3.Service, config *config.GceConfig, component string) (map[string]*v3.MetricDescriptor, error) {

prometheus-to-sd/translator/translator.go

@@ -103,7 +103,7 @@ func filterWhitelisted(allMetrics map[string]*dto.MetricFamily, whitelisted []st
 		if family, found := allMetrics[w]; found {
 			res[w] = family
 		} else {
-			glog.V(4).Infof("Whitelisted metric %s not present in Prometheus endpoint.", w)
+			glog.V(3).Infof("Whitelisted metric %s not present in Prometheus endpoint.", w)
 		}
 	}
 	return res
@@ -114,7 +114,7 @@ func translateFamily(config *config.CommonConfig,
 	startTime time.Time,
 	cache *MetricDescriptorCache) ([]*v3.TimeSeries, error) {
 
-	glog.V(4).Infof("Translating metric family %v", family.GetName())
+	glog.V(3).Infof("Translating metric family %v from component", family.GetName(), config.ComponentName)
 	var ts []*v3.TimeSeries
 	if _, found := supportedMetricTypes[family.GetType()]; !found {
 		return ts, fmt.Errorf("Metric type %v of family %s not supported", family.GetType(), family.GetName())