Add support for server side bucket replication (#9882)

pkg/bucket/replication/destination.go

@@ -0,0 +1,118 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package replication
+
+import (
+	"encoding/xml"
+	"fmt"
+	"strings"
+
+	"github.com/minio/minio/pkg/wildcard"
+)
+
+// DestinationARNPrefix - destination ARN prefix as per AWS S3 specification.
+const DestinationARNPrefix = "arn:aws:s3:::"
+
+// Destination - destination in ReplicationConfiguration.
+type Destination struct {
+	XMLName      xml.Name `xml:"Destination" json:"Destination"`
+	Bucket       string   `xml:"Bucket" json:"Bucket"`
+	StorageClass string   `xml:"StorageClass" json:"StorageClass"`
+	//EncryptionConfiguration TODO: not needed for MinIO
+}
+
+func (d Destination) isValidStorageClass() bool {
+	if d.StorageClass == "" {
+		return true
+	}
+	return d.StorageClass == "STANDARD" || d.StorageClass == "REDUCED_REDUNDANCY"
+}
+
+// IsValid - checks whether Destination is valid or not.
+func (d Destination) IsValid() bool {
+	return d.Bucket != "" || !d.isValidStorageClass()
+}
+
+func (d Destination) String() string {
+	return DestinationARNPrefix + d.Bucket
+}
+
+// MarshalXML - encodes to XML data.
+func (d Destination) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	if err := e.EncodeToken(start); err != nil {
+		return err
+	}
+	if err := e.EncodeElement(d.String(), xml.StartElement{Name: xml.Name{Local: "Bucket"}}); err != nil {
+		return err
+	}
+	if d.StorageClass != "" {
+		if err := e.EncodeElement(d.StorageClass, xml.StartElement{Name: xml.Name{Local: "StorageClass"}}); err != nil {
+			return err
+		}
+	}
+	return e.EncodeToken(xml.EndElement{Name: start.Name})
+}
+
+// UnmarshalXML - decodes XML data.
+func (d *Destination) UnmarshalXML(dec *xml.Decoder, start xml.StartElement) (err error) {
+	// Make subtype to avoid recursive UnmarshalXML().
+	type destination Destination
+	dest := destination{}
+
+	if err := dec.DecodeElement(&dest, &start); err != nil {
+		return err
+	}
+	parsedDest, err := parseDestination(dest.Bucket)
+	if err != nil {
+		return err
+	}
+	if dest.StorageClass != "" {
+		switch dest.StorageClass {
+		case "STANDARD", "REDUCED_REDUNDANCY":
+		default:
+			return fmt.Errorf("unknown storage class %v", dest.StorageClass)
+		}
+	}
+	parsedDest.StorageClass = dest.StorageClass
+	*d = parsedDest
+	return nil
+}
+
+// Validate - validates Resource is for given bucket or not.
+func (d Destination) Validate(bucketName string) error {
+	if !d.IsValid() {
+		return Errorf("invalid destination")
+	}
+
+	if !wildcard.Match(d.Bucket, bucketName) {
+		return Errorf("bucket name does not match")
+	}
+	return nil
+}
+
+// parseDestination - parses string to Destination.
+func parseDestination(s string) (Destination, error) {
+	if !strings.HasPrefix(s, DestinationARNPrefix) {
+		return Destination{}, Errorf("invalid destination '%v'", s)
+	}
+
+	bucketName := strings.TrimPrefix(s, DestinationARNPrefix)
+
+	return Destination{
+		Bucket: bucketName,
+	}, nil
+}