iceberg: add resource-group proposal controls (#8668)

* iceberg: add resource-group proposal controls

* iceberg: tighten resource group config validation

weed/plugin/worker/iceberg/resource_groups.go

@@ -0,0 +1,111 @@
+package iceberg
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/seaweedfs/seaweedfs/weed/pb/plugin_pb"
+)
+
+const (
+	resourceGroupNone            = "none"
+	resourceGroupBucket          = "bucket"
+	resourceGroupNamespace       = "namespace"
+	resourceGroupBucketNamespace = "bucket_namespace"
+)
+
+type resourceGroupConfig struct {
+	GroupBy           string
+	MaxTablesPerGroup int64
+}
+
+func readResourceGroupConfig(values map[string]*plugin_pb.ConfigValue) (resourceGroupConfig, error) {
+	groupBy := strings.TrimSpace(strings.ToLower(readStringConfig(values, "resource_group_by", "")))
+	if groupBy == "" {
+		groupBy = resourceGroupNone
+	}
+
+	switch groupBy {
+	case resourceGroupNone, resourceGroupBucket, resourceGroupNamespace, resourceGroupBucketNamespace:
+	default:
+		return resourceGroupConfig{}, fmt.Errorf("invalid resource_group_by %q (valid: none, bucket, namespace, bucket_namespace)", groupBy)
+	}
+
+	maxTablesPerGroup := readInt64Config(values, "max_tables_per_resource_group", 0)
+	if maxTablesPerGroup < 0 {
+		return resourceGroupConfig{}, fmt.Errorf("max_tables_per_resource_group must be >= 0, got %d", maxTablesPerGroup)
+	}
+	if groupBy == resourceGroupNone && maxTablesPerGroup > 0 {
+		return resourceGroupConfig{}, fmt.Errorf("max_tables_per_resource_group requires resource_group_by to be set")
+	}
+
+	return resourceGroupConfig{
+		GroupBy:           groupBy,
+		MaxTablesPerGroup: maxTablesPerGroup,
+	}, nil
+}
+
+func (c resourceGroupConfig) enabled() bool {
+	return c.GroupBy != "" && c.GroupBy != resourceGroupNone
+}
+
+func resourceGroupKey(info tableInfo, groupBy string) string {
+	switch groupBy {
+	case resourceGroupBucket:
+		return info.BucketName
+	case resourceGroupNamespace:
+		return info.Namespace
+	case resourceGroupBucketNamespace:
+		return info.BucketName + "/" + info.Namespace
+	default:
+		return ""
+	}
+}
+
+func selectTablesByResourceGroup(tables []tableInfo, cfg resourceGroupConfig, maxResults int) ([]tableInfo, bool) {
+	if !cfg.enabled() {
+		if maxResults > 0 && len(tables) > maxResults {
+			return tables[:maxResults], true
+		}
+		return tables, false
+	}
+
+	grouped := make(map[string][]tableInfo)
+	groupOrder := make([]string, 0)
+	for _, table := range tables {
+		key := resourceGroupKey(table, cfg.GroupBy)
+		if _, ok := grouped[key]; !ok {
+			groupOrder = append(groupOrder, key)
+		}
+		grouped[key] = append(grouped[key], table)
+	}
+
+	selected := make([]tableInfo, 0, len(tables))
+	selectedPerGroup := make(map[string]int64)
+	for {
+		progress := false
+		for _, key := range groupOrder {
+			if maxResults > 0 && len(selected) >= maxResults {
+				return selected, len(selected) < len(tables)
+			}
+			if cfg.MaxTablesPerGroup > 0 && selectedPerGroup[key] >= cfg.MaxTablesPerGroup {
+				continue
+			}
+
+			queue := grouped[key]
+			if len(queue) == 0 {
+				continue
+			}
+
+			selected = append(selected, queue[0])
+			grouped[key] = queue[1:]
+			selectedPerGroup[key]++
+			progress = true
+		}
+		if !progress {
+			break
+		}
+	}
+
+	return selected, len(selected) < len(tables)
+}