[#1337] blobovniczatree: Add rebuild by fill percent

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/blobstor/blobovniczatree/rebuild.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"errors"
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -59,7 +60,7 @@ func (b *Blobovniczas) Rebuild(ctx context.Context, prm common.RebuildPrm) (comm
 	b.log.Debug(logs.BlobovniczaTreeCompletedPreviousRebuildSuccess)
 
 	b.log.Debug(logs.BlobovniczaTreeCollectingDBToRebuild)
-	dbsToMigrate, err := b.getDBsToRebuild(ctx)
+	dbsToMigrate, err := b.getDBsToRebuild(ctx, prm.Action)
 	if err != nil {
 		b.log.Warn(logs.BlobovniczaTreeCollectingDBToRebuildFailed, zap.Error(err))
 		success = false
@@ -93,7 +94,33 @@ func (b *Blobovniczas) migrateDBs(ctx context.Context, dbs []string, prm common.
 	return res, nil
 }
 
-func (b *Blobovniczas) getDBsToRebuild(ctx context.Context) ([]string, error) {
+func (b *Blobovniczas) getDBsToRebuild(ctx context.Context, action common.RebuildAction) ([]string, error) {
+	schemaChange := make(map[string]struct{})
+	fillPercent := make(map[string]struct{})
+	var err error
+	if action.SchemaChange {
+		schemaChange, err = b.selectDBsDoNotMatchSchema(ctx)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if action.FillPercent {
+		fillPercent, err = b.selectDBsDoNotMatchFillPercent(ctx, action.FillPercentValue)
+		if err != nil {
+			return nil, err
+		}
+	}
+	for k := range fillPercent {
+		schemaChange[k] = struct{}{}
+	}
+	result := make([]string, 0, len(schemaChange))
+	for db := range schemaChange {
+		result = append(result, db)
+	}
+	return result, nil
+}
+
+func (b *Blobovniczas) selectDBsDoNotMatchSchema(ctx context.Context) (map[string]struct{}, error) {
 	dbsToMigrate := make(map[string]struct{})
 	if err := b.iterateExistingDBPaths(ctx, func(s string) (bool, error) {
 		dbsToMigrate[s] = struct{}{}
@@ -107,13 +134,69 @@ func (b *Blobovniczas) getDBsToRebuild(ctx context.Context) ([]string, error) {
 	}); err != nil {
 		return nil, err
 	}
-	result := make([]string, 0, len(dbsToMigrate))
-	for db := range dbsToMigrate {
-		result = append(result, db)
+	return dbsToMigrate, nil
+}
+
+func (b *Blobovniczas) selectDBsDoNotMatchFillPercent(ctx context.Context, target int) (map[string]struct{}, error) {
+	if target <= 0 || target > 100 {
+		return nil, fmt.Errorf("invalid fill percent value %d: must be (0; 100]", target)
+	}
+	result := make(map[string]struct{})
+	if err := b.iterateDeepest(ctx, oid.Address{}, func(lvlPath string) (bool, error) {
+		dir := filepath.Join(b.rootPath, lvlPath)
+		entries, err := os.ReadDir(dir)
+		if os.IsNotExist(err) { // non initialized tree
+			return false, nil
+		}
+		if err != nil {
+			return false, err
+		}
+		hasDBs := false
+		// db with maxIdx could be an active, so it should not be rebuilded
+		var maxIdx uint64
+		for _, e := range entries {
+			if e.IsDir() || strings.HasSuffix(e.Name(), rebuildSuffix) {
+				continue
+			}
+			hasDBs = true
+			maxIdx = max(u64FromHexString(e.Name()), maxIdx)
+		}
+		if !hasDBs {
+			return false, nil
+		}
+		for _, e := range entries {
+			if e.IsDir() || strings.HasSuffix(e.Name(), rebuildSuffix) {
+				continue
+			}
+			if u64FromHexString(e.Name()) == maxIdx {
+				continue
+			}
+			path := filepath.Join(lvlPath, e.Name())
+			resettlementRequired, err := b.fillPercentIsLow(path, target)
+			if err != nil {
+				return false, err
+			}
+			if resettlementRequired {
+				result[path] = struct{}{}
+			}
+		}
+		return false, nil
+	}); err != nil {
+		return nil, err
 	}
 	return result, nil
 }
 
+func (b *Blobovniczas) fillPercentIsLow(path string, target int) (bool, error) {
+	shDB := b.getBlobovnicza(path)
+	blz, err := shDB.Open()
+	if err != nil {
+		return false, err
+	}
+	defer shDB.Close()
+	return blz.FillPercent() < target, nil
+}
+
 func (b *Blobovniczas) rebuildDB(ctx context.Context, path string, meta common.MetaStorage, limiter common.ConcurrentWorkersLimiter) (uint64, error) {
 	shDB := b.getBlobovnicza(path)
 	blz, err := shDB.Open()