extend virtual folders support to all storage backends

Fixes #241

vfs/azblobfs.go

@@ -36,8 +36,10 @@ var maxTryTimeout = time.Hour * 24 * 365
 
 // AzureBlobFs is a Fs implementation for Azure Blob storage.
 type AzureBlobFs struct {
-	connectionID   string
-	localTempDir   string
+	connectionID string
+	localTempDir string
+	// if not empty this fs is mouted as virtual folder in the specified path
+	mountPath      string
 	config         *AzBlobFsConfig
 	svc            *azblob.ServiceURL
 	containerURL   azblob.ContainerURL
@@ -50,10 +52,14 @@ func init() {
 }
 
 // NewAzBlobFs returns an AzBlobFs object that allows to interact with Azure Blob storage
-func NewAzBlobFs(connectionID, localTempDir string, config AzBlobFsConfig) (Fs, error) {
+func NewAzBlobFs(connectionID, localTempDir, mountPath string, config AzBlobFsConfig) (Fs, error) {
+	if localTempDir == "" {
+		localTempDir = filepath.Clean(os.TempDir())
+	}
 	fs := &AzureBlobFs{
 		connectionID:   connectionID,
 		localTempDir:   localTempDir,
+		mountPath:      mountPath,
 		config:         &config,
 		ctxTimeout:     30 * time.Second,
 		ctxLongTimeout: 300 * time.Second,
@@ -89,7 +95,7 @@ func NewAzBlobFs(connectionID, localTempDir string, config AzBlobFsConfig) (Fs,
 		parts := azblob.NewBlobURLParts(*u)
 		if parts.ContainerName != "" {
 			if fs.config.Container != "" && fs.config.Container != parts.ContainerName {
-				return fs, fmt.Errorf("Container name in SAS URL %#v and container provided %#v do not match",
+				return fs, fmt.Errorf("container name in SAS URL %#v and container provided %#v do not match",
 					parts.ContainerName, fs.config.Container)
 			}
 			fs.svc = nil
@@ -282,7 +288,7 @@ func (fs *AzureBlobFs) Rename(source, target string) error {
 			return err
 		}
 		if hasContents {
-			return fmt.Errorf("Cannot rename non empty directory: %#v", source)
+			return fmt.Errorf("cannot rename non empty directory: %#v", source)
 		}
 	}
 	dstBlobURL := fs.containerURL.NewBlobURL(target)
@@ -318,7 +324,7 @@ func (fs *AzureBlobFs) Rename(source, target string) error {
 		}
 	}
 	if copyStatus != azblob.CopyStatusSuccess {
-		err := fmt.Errorf("Copy failed with status: %s", copyStatus)
+		err := fmt.Errorf("copy failed with status: %s", copyStatus)
 		metrics.AZCopyObjectCompleted(err)
 		return err
 	}
@@ -334,7 +340,7 @@ func (fs *AzureBlobFs) Remove(name string, isDir bool) error {
 			return err
 		}
 		if hasContents {
-			return fmt.Errorf("Cannot remove non empty directory: %#v", name)
+			return fmt.Errorf("cannot remove non empty directory: %#v", name)
 		}
 	}
 	blobBlockURL := fs.containerURL.NewBlockBlobURL(name)
@@ -359,6 +365,11 @@ func (fs *AzureBlobFs) Mkdir(name string) error {
 	return w.Close()
 }
 
+// MkdirAll does nothing, we don't have folder
+func (*AzureBlobFs) MkdirAll(name string, uid int, gid int) error {
+	return nil
+}
+
 // Symlink creates source as a symbolic link to target.
 func (*AzureBlobFs) Symlink(source, target string) error {
 	return ErrVfsUnsupported
@@ -528,7 +539,7 @@ func (*AzureBlobFs) IsNotSupported(err error) bool {
 // CheckRootPath creates the specified local root directory if it does not exists
 func (fs *AzureBlobFs) CheckRootPath(username string, uid int, gid int) bool {
 	// we need a local directory for temporary files
-	osFs := NewOsFs(fs.ConnectionID(), fs.localTempDir, nil)
+	osFs := NewOsFs(fs.ConnectionID(), fs.localTempDir, "")
 	return osFs.CheckRootPath(username, uid, gid)
 }
 
@@ -607,6 +618,9 @@ func (fs *AzureBlobFs) GetRelativePath(name string) string {
 		}
 		rel = path.Clean("/" + strings.TrimPrefix(rel, "/"+fs.config.KeyPrefix))
 	}
+	if fs.mountPath != "" {
+		rel = path.Join(fs.mountPath, rel)
+	}
 	return rel
 }
 
@@ -675,6 +689,9 @@ func (*AzureBlobFs) HasVirtualFolders() bool {
 
 // ResolvePath returns the matching filesystem path for the specified sftp path
 func (fs *AzureBlobFs) ResolvePath(virtualPath string) (string, error) {
+	if fs.mountPath != "" {
+		virtualPath = strings.TrimPrefix(virtualPath, fs.mountPath)
+	}
 	if !path.IsAbs(virtualPath) {
 		virtualPath = path.Clean("/" + virtualPath)
 	}