Fix path prefix handling in S3-to-S3 copy

Makefile

@@ -41,6 +41,7 @@ fixture:
 	aws s3 --endpoint-url http://localhost:4572 cp README.md s3://s3-source/foo/
 	aws s3 --endpoint-url http://localhost:4572 cp README.md s3://s3-source/bar/baz/
 	aws s3 --endpoint-url http://localhost:4572 mb s3://s3-destination
+	aws s3 --endpoint-url http://localhost:4572 mb s3://s3-destination2
 	aws s3 --endpoint-url http://localhost:4572 mb s3://example-bucket-escaped
 	aws s3 --endpoint-url http://localhost:4572 mb s3://example-bucket-upload
 	aws s3 --endpoint-url http://localhost:4572 cp README.md s3://example-bucket-upload/dest_only_file

s3sync.go

@@ -3,7 +3,7 @@
 // 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
+//	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,
@@ -253,15 +253,17 @@ func (m *Manager) syncS3ToLocal(ctx context.Context, chJob chan func(), sourcePa
 }
 
 func (m *Manager) copyS3ToS3(ctx context.Context, file *fileInfo, sourcePath *s3Path, destPath *s3Path) error {
-	println("Copying", file.name, "to", destPath.String())
+	copySource := filepath.ToSlash(filepath.Join(sourcePath.bucket, sourcePath.bucketPrefix, file.name))
+	destinationKey := filepath.ToSlash(filepath.Join(destPath.bucketPrefix, file.name))
+	println("Copying from", copySource, "to key", destinationKey, "in bucket", destPath.bucket)
 	if m.dryrun {
 		return nil
 	}
 
 	_, err := m.s3.CopyObject(&s3.CopyObjectInput{
 		Bucket:     aws.String(destPath.bucket),
-		CopySource: aws.String(sourcePath.bucket + "/" + file.name),
-		Key:        aws.String(file.name),
+		CopySource: aws.String(copySource),
+		Key:        aws.String(destinationKey),
 		ACL:        m.acl,
 	})
 

s3sync_test.go

@@ -38,16 +38,6 @@ func TestS3syncNotImplemented(t *testing.T) {
 	}
 }
 
-func TestS3ToS3(t *testing.T) {
-	m := New(getSession())
-
-	err := m.Sync("s3://s3-source", "s3://s3-destination")
-
-	if err != nil {
-		t.Fatal(err.Error())
-	}
-}
-
 func TestS3sync(t *testing.T) {
 	data, err := ioutil.ReadFile(dummyFilename)
 	if err != nil {
@@ -163,6 +153,25 @@ func TestS3sync(t *testing.T) {
 		}
 	})
 
+	t.Run("S3ToS3CopyWithPrefix", func(t *testing.T) {
+		if err := New(getSession()).Sync("s3://s3-source/bar", "s3://s3-destination2/hoge"); err != nil {
+			t.Fatal("Sync should be successful", err)
+		}
+
+		objs := listObjectsSorted(t, "s3-destination2")
+		if n := len(objs); n != 1 {
+			t.Fatalf("Number of the files should be 1 (result: %v)", objs)
+		}
+		for _, obj := range objs {
+			if obj.size != dummyFileSize {
+				t.Errorf("Object size should be %d, actual %d", dummyFileSize, obj.size)
+			}
+		}
+		if objs[0].path != "hoge/baz/README.md" {
+			t.Error("Unexpected keys", objs)
+		}
+	})
+
 	t.Run("Upload", func(t *testing.T) {
 		temp, err := ioutil.TempDir("", "s3synctest")
 		defer os.RemoveAll(temp)