changing ordering so AWS API is only called if cache has expired (#9136)

pkg/api/cloudwatch/metrics.go

@@ -292,11 +292,6 @@ func getAllMetrics(cwData *datasourceInfo) (cloudwatch.ListMetricsOutput, error)
 var metricsCacheLock sync.Mutex
 
 func getMetricsForCustomMetrics(dsInfo *datasourceInfo, getAllMetrics func(*datasourceInfo) (cloudwatch.ListMetricsOutput, error)) ([]string, error) {
-	result, err := getAllMetrics(dsInfo)
-	if err != nil {
-		return []string{}, err
-	}
-
 	metricsCacheLock.Lock()
 	defer metricsCacheLock.Unlock()
 
@@ -314,6 +309,10 @@ func getMetricsForCustomMetrics(dsInfo *datasourceInfo, getAllMetrics func(*data
 	if customMetricsMetricsMap[dsInfo.Profile][dsInfo.Region][dsInfo.Namespace].Expire.After(time.Now()) {
 		return customMetricsMetricsMap[dsInfo.Profile][dsInfo.Region][dsInfo.Namespace].Cache, nil
 	}
+	result, err := getAllMetrics(dsInfo)
+	if err != nil {
+		return []string{}, err
+	}
 	customMetricsMetricsMap[dsInfo.Profile][dsInfo.Region][dsInfo.Namespace].Cache = make([]string, 0)
 	customMetricsMetricsMap[dsInfo.Profile][dsInfo.Region][dsInfo.Namespace].Expire = time.Now().Add(5 * time.Minute)
 
@@ -330,11 +329,6 @@ func getMetricsForCustomMetrics(dsInfo *datasourceInfo, getAllMetrics func(*data
 var dimensionsCacheLock sync.Mutex
 
 func getDimensionsForCustomMetrics(dsInfo *datasourceInfo, getAllMetrics func(*datasourceInfo) (cloudwatch.ListMetricsOutput, error)) ([]string, error) {
-	result, err := getAllMetrics(dsInfo)
-	if err != nil {
-		return []string{}, err
-	}
-
 	dimensionsCacheLock.Lock()
 	defer dimensionsCacheLock.Unlock()
 
@@ -352,6 +346,10 @@ func getDimensionsForCustomMetrics(dsInfo *datasourceInfo, getAllMetrics func(*d
 	if customMetricsDimensionsMap[dsInfo.Profile][dsInfo.Region][dsInfo.Namespace].Expire.After(time.Now()) {
 		return customMetricsDimensionsMap[dsInfo.Profile][dsInfo.Region][dsInfo.Namespace].Cache, nil
 	}
+	result, err := getAllMetrics(dsInfo)
+	if err != nil {
+		return []string{}, err
+	}
 	customMetricsDimensionsMap[dsInfo.Profile][dsInfo.Region][dsInfo.Namespace].Cache = make([]string, 0)
 	customMetricsDimensionsMap[dsInfo.Profile][dsInfo.Region][dsInfo.Namespace].Expire = time.Now().Add(5 * time.Minute)