only look for metadata if batch replication asks for metadata filters (minio#18082)

This PR changes the StatObject() to be must have for non-minio source
to being a conditional API call.

- Calls StatObject() when needed
- Calls GetObjectTagging() when needed

These calls if we do without these conditionals can cause a lot of
delays, so we avoid them if not needed in more common scenario.

Author: harshavardhana

cmd/batch-handlers.go

@@ -37,6 +37,7 @@ import (
 	"github.com/dustin/go-humanize"
 	"github.com/lithammer/shortuuid/v4"
 	"github.com/minio/madmin-go/v3"
+	"github.com/minio/minio-go/v7"
 	miniogo "github.com/minio/minio-go/v7"
 	"github.com/minio/minio-go/v7/pkg/credentials"
 	"github.com/minio/minio-go/v7/pkg/encrypt"
@@ -269,6 +270,10 @@ func (r *BatchJobReplicateV1) StartFromSource(ctx context.Context, api ObjectLay
 	}
 	rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
 
+	isTags := len(r.Flags.Filter.Tags) != 0
+	isMetadata := len(r.Flags.Filter.Metadata) != 0
+	isStorageClassOnly := len(r.Flags.Filter.Metadata) == 1 && strings.EqualFold(r.Flags.Filter.Metadata[0].Key, xhttp.AmzStorageClass)
+
 	skip := func(oi ObjectInfo) (ok bool) {
 		if r.Flags.Filter.OlderThan > 0 && time.Since(oi.ModTime) < r.Flags.Filter.OlderThan {
 			// skip all objects that are newer than specified older duration
@@ -289,7 +294,8 @@ func (r *BatchJobReplicateV1) StartFromSource(ctx context.Context, api ObjectLay
 			// skip all objects that are created after the specified time.
 			return true
 		}
-		if len(r.Flags.Filter.Tags) > 0 {
+
+		if isTags {
 			// Only parse object tags if tags filter is specified.
 			tagMap := map[string]string{}
 			tagStr := oi.UserTags
@@ -312,23 +318,19 @@ func (r *BatchJobReplicateV1) StartFromSource(ctx context.Context, api ObjectLay
 			return false
 		}
 
-		if len(r.Flags.Filter.Metadata) > 0 {
-			for _, kv := range r.Flags.Filter.Metadata {
-				for k, v := range oi.UserDefined {
-					if !stringsHasPrefixFold(k, "x-amz-meta-") && !isStandardHeader(k) {
-						continue
-					}
-					// We only need to match x-amz-meta or standardHeaders
-					if kv.Match(BatchJobKV{Key: k, Value: v}) {
-						return true
-					}
+		for _, kv := range r.Flags.Filter.Metadata {
+			for k, v := range oi.UserDefined {
+				if !stringsHasPrefixFold(k, "x-amz-meta-") && !isStandardHeader(k) {
+					continue
+				}
+				// We only need to match x-amz-meta or standardHeaders
+				if kv.Match(BatchJobKV{Key: k, Value: v}) {
+					return true
 				}
 			}
-
-			// None of the provided metadata filters match skip the object.
-			return false
 		}
 
+		// None of the provided filters match
 		return false
 	}
 
@@ -383,17 +385,32 @@ func (r *BatchJobReplicateV1) StartFromSource(ctx context.Context, api ObjectLay
 		for obj := range objInfoCh {
 			oi := toObjectInfo(r.Source.Bucket, obj.Key, obj)
 			if !minioSrc {
-				oi2, err := c.StatObject(ctx, r.Source.Bucket, obj.Key, miniogo.StatObjectOptions{})
-				if err == nil {
-					oi = toObjectInfo(r.Source.Bucket, obj.Key, oi2)
-				} else {
-					if isErrMethodNotAllowed(ErrorRespToObjectError(err, r.Source.Bucket, obj.Key)) ||
-						isErrObjectNotFound(ErrorRespToObjectError(err, r.Source.Bucket, obj.Key)) {
+				// Check if metadata filter was requested and it is expected to have
+				// all user metadata or just storageClass. If its only storageClass
+				// List() already returns relevant information for filter to be applied.
+				if isMetadata && !isStorageClassOnly {
+					oi2, err := c.StatObject(ctx, r.Source.Bucket, obj.Key, miniogo.StatObjectOptions{})
+					if err == nil {
+						oi = toObjectInfo(r.Source.Bucket, obj.Key, oi2)
+					} else {
+						if !isErrMethodNotAllowed(ErrorRespToObjectError(err, r.Source.Bucket, obj.Key)) &&
+							!isErrObjectNotFound(ErrorRespToObjectError(err, r.Source.Bucket, obj.Key)) {
+							logger.LogIf(ctx, err)
+						}
+						continue
+					}
+				}
+				if isTags {
+					tags, err := c.GetObjectTagging(ctx, r.Source.Bucket, obj.Key, minio.GetObjectTaggingOptions{})
+					if err == nil {
+						oi.UserTags = tags.String()
+					} else {
+						if !isErrMethodNotAllowed(ErrorRespToObjectError(err, r.Source.Bucket, obj.Key)) &&
+							!isErrObjectNotFound(ErrorRespToObjectError(err, r.Source.Bucket, obj.Key)) {
+							logger.LogIf(ctx, err)
+						}
 						continue
 					}
-					logger.LogIf(ctx, err)
-					cancel()
-					return err
 				}
 			}
 			if skip(oi) {
@@ -481,17 +498,25 @@ func toObjectInfo(bucket, object string, objInfo miniogo.ObjectInfo) ObjectInfo
 		ReplicationStatusInternal: objInfo.ReplicationStatus,
 		UserTags:                  tags.String(),
 	}
+
 	oi.UserDefined = make(map[string]string, len(objInfo.Metadata))
 	for k, v := range objInfo.Metadata {
 		oi.UserDefined[k] = v[0]
 	}
+
 	ce, ok := oi.UserDefined[xhttp.ContentEncoding]
 	if !ok {
 		ce, ok = oi.UserDefined[strings.ToLower(xhttp.ContentEncoding)]
 	}
 	if ok {
 		oi.ContentEncoding = ce
 	}
+
+	_, ok = oi.UserDefined[xhttp.AmzStorageClass]
+	if !ok {
+		oi.UserDefined[xhttp.AmzStorageClass] = objInfo.StorageClass
+	}
+
 	return oi
 }
 
@@ -821,7 +846,7 @@ func (r *BatchJobReplicateV1) Start(ctx context.Context, api ObjectLayer, job Ba
 	}
 	rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
 
-	skip := func(info FileInfo) (ok bool) {
+	selectObj := func(info FileInfo) (ok bool) {
 		if r.Flags.Filter.OlderThan > 0 && time.Since(info.ModTime) < r.Flags.Filter.OlderThan {
 			// skip all objects that are newer than specified older duration
 			return false
@@ -931,7 +956,7 @@ func (r *BatchJobReplicateV1) Start(ctx context.Context, api ObjectLayer, job Ba
 		results := make(chan ObjectInfo, 100)
 		if err := api.Walk(ctx, r.Source.Bucket, r.Source.Prefix, results, ObjectOptions{
 			WalkMarker: lastObject,
-			WalkFilter: skip,
+			WalkFilter: selectObj,
 		}); err != nil {
 			cancel()
 			// Do not need to retry if we can't list objects on source.