Refactor metricstore. Initial stub for cluster/ subcluster specific retention times

internal/metricstore/config.go

@@ -33,8 +33,19 @@ type MetricStoreConfig struct {
 		DumpToFile string `json:"dump-to-file"`
 		EnableGops bool   `json:"gops"`
 	} `json:"debug"`
+	// Global default retention duration
 	RetentionInMemory string `json:"retention-in-memory"`
-	Archive           struct {
+	// Per-cluster retention overrides
+	Clusters []struct {
+		Cluster           string `json:"cluster"`
+		RetentionInMemory string `json:"retention-in-memory"`
+		// Per-subcluster retention overrides within this cluster
+		SubClusters []struct {
+			SubCluster        string `json:"subcluster"`
+			RetentionInMemory string `json:"retention-in-memory"`
+		} `json:"subclusters,omitempty"`
+	} `json:"clusters,omitempty"`
+	Archive struct {
 		Interval      string `json:"interval"`
 		RootDir       string `json:"directory"`
 		DeleteInstead bool   `json:"delete-instead"`
@@ -50,6 +61,14 @@ type MetricStoreConfig struct {
 
 var Keys MetricStoreConfig
 
+type retentionConfig struct {
+	global        time.Duration
+	clusterMap    map[string]time.Duration
+	subClusterMap map[string]map[string]time.Duration
+}
+
+var retentionLookup *retentionConfig
+
 // AggregationStrategy for aggregation over multiple values at different cpus/sockets/..., not time!
 type AggregationStrategy int
 
@@ -113,3 +132,52 @@ func AddMetric(name string, metric MetricConfig) error {
 
 	return nil
 }
+
+func GetRetentionDuration(cluster, subCluster string) (time.Duration, error) {
+	if retentionLookup == nil {
+		return 0, fmt.Errorf("[METRICSTORE]> retention configuration not initialized")
+	}
+
+	if subCluster != "" {
+		if subMap, ok := retentionLookup.subClusterMap[cluster]; ok {
+			if retention, ok := subMap[subCluster]; ok {
+				return retention, nil
+			}
+		}
+	}
+
+	if retention, ok := retentionLookup.clusterMap[cluster]; ok {
+		return retention, nil
+	}
+
+	return retentionLookup.global, nil
+}
+
+// GetShortestRetentionDuration returns the shortest configured retention duration
+// across all levels (global, cluster, and subcluster configurations).
+// Returns 0 if retentionLookup is not initialized or global retention is not set.
+func GetShortestRetentionDuration() time.Duration {
+	if retentionLookup == nil || retentionLookup.global <= 0 {
+		return 0
+	}
+
+	shortest := retentionLookup.global
+
+	// Check all cluster-level retention durations
+	for _, clusterRetention := range retentionLookup.clusterMap {
+		if clusterRetention > 0 && clusterRetention < shortest {
+			shortest = clusterRetention
+		}
+	}
+
+	// Check all subcluster-level retention durations
+	for _, subClusterMap := range retentionLookup.subClusterMap {
+		for _, scRetention := range subClusterMap {
+			if scRetention > 0 && scRetention < shortest {
+				shortest = scRetention
+			}
+		}
+	}
+
+	return shortest
+}