dropbox: basics of metadata in Dropbox datastore working

dropbox/dropbox.go

@@ -13,6 +13,10 @@ Can only have 25,000 objects in a directory
 Setting metadata is problematic!  Might have to use a database
 
 Md5sum has to download the file
+
+FIXME do we need synchronisation for any of the dropbox calls?
+
+FIXME need to delete metadata when we delete files!
 */
 
 import (
@@ -25,6 +29,7 @@ import (
 	"time"
 
 	"github.com/ncw/rclone/fs"
+	"github.com/ncw/swift"
 	"github.com/stacktic/dropbox"
 )
 
@@ -34,6 +39,10 @@ const (
 	rcloneAppSecret = "1n9m04y2zx7bf26"
 	uploadChunkSize = 64 * 1024                    // chunk size for upload
 	metadataLimit   = dropbox.MetadataLimitDefault // max items to fetch at once
+	datastoreName   = "rclone"
+	tableName       = "metadata"
+	md5sumField     = "md5sum"
+	mtimeField      = "mtime"
 )
 
 // Register with Fs
@@ -87,6 +96,9 @@ type FsDropbox struct {
 	db               *dropbox.Dropbox // the connection to the dropbox server
 	root             string           // the path we are working on
 	slashRoot        string           // root with "/" prefix and postix
+	datastoreManager *dropbox.DatastoreManager
+	datastore        *dropbox.Datastore
+	table            *dropbox.Table
 }
 
 // FsObjectDropbox describes a dropbox object
@@ -153,25 +165,40 @@ func NewFs(name, path string) (fs.Fs, error) {
 	// Authorize the client
 	db.SetAccessToken(token)
 
+	// Make a db to store rclone metadata in
+	f.datastoreManager = db.NewDatastoreManager()
+
+	// Open the rclone datastore
+	f.datastore, err = f.datastoreManager.OpenDatastore(datastoreName)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get the table we are using
+	f.table, err = f.datastore.GetTable(tableName)
+	if err != nil {
+		return nil, err
+	}
+
 	return f, nil
 }
 
 // Return an FsObject from a path
 func (f *FsDropbox) newFsObjectWithInfo(remote string, info *dropbox.Entry) (fs.Object, error) {
-	fs := &FsObjectDropbox{
+	o := &FsObjectDropbox{
 		dropbox: f,
 		remote:  remote,
 	}
-	if info != nil {
-		fs.setMetaData(info)
+	if info == nil {
+		o.setMetadataFromEntry(info)
 	} else {
-		err := fs.readMetaData() // reads info and meta, returning an error
+		err := o.readEntryAndSetMetadata()
 		if err != nil {
 			// logged already fs.Debug("Failed to read info: %s", err)
 			return nil, err
 		}
 	}
-	return fs, nil
+	return o, nil
 }
 
 // Return an FsObject from a path
@@ -304,7 +331,7 @@ func (f *FsDropbox) Rmdir() error {
 
 // Return the precision
 func (fs *FsDropbox) Precision() time.Duration {
-	return time.Second
+	return time.Nanosecond
 }
 
 // Purge deletes all the files and the container
@@ -342,17 +369,26 @@ func (o *FsObjectDropbox) Md5sum() (string, error) {
 	if o.md5sum != "" {
 		return o.md5sum, nil
 	}
-	in, err := o.Open()
+	err := o.readMetaData()
 	if err != nil {
-		return "", err
+		fs.Log(o, "Failed to read metadata: %s", err)
+		return "", fmt.Errorf("Failed to read metadata: %s", err)
+
 	}
-	defer in.Close()
-	hash := md5.New()
-	_, err = io.Copy(hash, in)
-	if err != nil {
-		return "", err
-	}
-	o.md5sum = fmt.Sprintf("%x", hash.Sum(nil))
+
+	// For pre-existing files which have no md5sum can read it and set it?
+
+	// in, err := o.Open()
+	// if err != nil {
+	// 	return "", err
+	// }
+	// defer in.Close()
+	// hash := md5.New()
+	// _, err = io.Copy(hash, in)
+	// if err != nil {
+	// 	return "", err
+	// }
+	// o.md5sum = fmt.Sprintf("%x", hash.Sum(nil))
 	return o.md5sum, nil
 }
 
@@ -361,28 +397,102 @@ func (o *FsObjectDropbox) Size() int64 {
 	return o.bytes
 }
 
-// setMetaData sets the fs data from a dropbox.Entry
-func (o *FsObjectDropbox) setMetaData(info *dropbox.Entry) {
+// setMetadataFromEntry sets the fs data from a dropbox.Entry
+//
+// This isn't a complete set of metadata and has an inacurate date
+func (o *FsObjectDropbox) setMetadataFromEntry(info *dropbox.Entry) {
 	o.bytes = int64(info.Bytes)
 	o.modTime = time.Time(info.ClientMtime)
 }
 
+// Reads the entry from dropbox
+func (o *FsObjectDropbox) readEntry() (*dropbox.Entry, error) {
+	entry, err := o.dropbox.db.Metadata(o.remotePath(), false, false, "", "", metadataLimit)
+	if err != nil {
+		fs.Debug(o, "Error reading file: %s", err)
+		return nil, fmt.Errorf("Error reading file: %s", err)
+	}
+	return entry, nil
+}
+
+// Read entry if not set and set metadata from it
+func (o *FsObjectDropbox) readEntryAndSetMetadata() error {
+	// Last resort set time from client
+	if !o.modTime.IsZero() {
+		return nil
+	}
+	entry, err := o.readEntry()
+	if err != nil {
+		return err
+	}
+	o.setMetadataFromEntry(entry)
+	return nil
+}
+
 // Returns the remote path for the object
 func (o *FsObjectDropbox) remotePath() string {
 	return o.dropbox.slashRoot + o.remote
 }
 
+// Returns the key for the metadata database
+func (o *FsObjectDropbox) metadataKey() string {
+	// FIXME lower case it?
+	key := o.dropbox.slashRoot + o.remote
+	return fmt.Sprintf("%x", md5.Sum([]byte(key)))
+}
+
 // readMetaData gets the info if it hasn't already been fetched
 func (o *FsObjectDropbox) readMetaData() (err error) {
-	if !o.modTime.IsZero() {
+	if o.md5sum != "" {
 		return nil
 	}
-	entry, err := o.dropbox.db.Metadata(o.remotePath(), false, false, "", "", metadataLimit)
+
+	record, err := o.dropbox.table.Get(o.metadataKey())
 	if err != nil {
-		fs.Debug(o, "Couldn't find directory: %s", err)
-		return fmt.Errorf("Couldn't find directory: %s", err)
+		fs.Debug(o, "Couldn't read metadata: %s", err)
+		record = nil
 	}
-	o.setMetaData(entry)
+
+	if record != nil {
+		// Read md5sum
+		md5sumInterface, ok, err := record.Get(md5sumField)
+		if err != nil {
+			return err
+		}
+		if !ok {
+			fs.Debug(o, "Couldn't find md5sum in record")
+		} else {
+			md5sum, ok := md5sumInterface.(string)
+			if !ok {
+				fs.Debug(o, "md5sum not a string")
+			} else {
+				o.md5sum = md5sum
+			}
+		}
+
+		// read mtime
+		mtimeInterface, ok, err := record.Get(mtimeField)
+		if err != nil {
+			return err
+		}
+		if !ok {
+			fs.Debug(o, "Couldn't find mtime in record")
+		} else {
+			mtime, ok := mtimeInterface.(string)
+			if !ok {
+				fs.Debug(o, "mtime not a string")
+			} else {
+				modTime, err := swift.FloatStringToTime(mtime)
+				if err != nil {
+					return err
+				}
+				o.modTime = modTime
+			}
+		}
+	}
+
+	// Last resort
+	o.readEntryAndSetMetadata()
 	return nil
 }
 
@@ -399,16 +509,45 @@ func (o *FsObjectDropbox) ModTime() time.Time {
 	return o.modTime
 }
 
+// Sets the modification time of the local fs object into the record
+// FIXME if we don't set md5sum what will that do?
+func (o *FsObjectDropbox) setModTimeAndMd5sum(modTime time.Time, md5sum string) error {
+	record, err := o.dropbox.table.GetOrInsert(o.metadataKey())
+	if err != nil {
+		return fmt.Errorf("Couldn't read record: %s", err)
+	}
+
+	if md5sum != "" {
+		err = record.Set(md5sumField, md5sum)
+		if err != nil {
+			return fmt.Errorf("Couldn't set md5sum record: %s", err)
+		}
+	}
+
+	if !modTime.IsZero() {
+		mtime := swift.TimeToFloatString(modTime)
+		err := record.Set(mtimeField, mtime)
+		if err != nil {
+			return fmt.Errorf("Couldn't set mtime record: %s", err)
+		}
+	}
+
+	err = o.dropbox.datastore.Commit()
+	if err != nil {
+		return fmt.Errorf("Failed to commit metadata changes: %s", err)
+	}
+	return nil
+}
+
 // Sets the modification time of the local fs object
+//
+// Commits the datastore
 func (o *FsObjectDropbox) SetModTime(modTime time.Time) {
-	err := o.readMetaData()
+	err := o.setModTimeAndMd5sum(modTime, "")
 	if err != nil {
 		fs.Stats.Error()
-		fs.Log(o, "Failed to read metadata: %s", err)
-		return
+		fs.Log(o, err.Error())
 	}
-	// fs.Stats.Error()
-	fs.Log(o, "FIXME can't update dropbox mtime")
 }
 
 // Is this object storable
@@ -428,13 +567,17 @@ func (o *FsObjectDropbox) Open() (in io.ReadCloser, err error) {
 //
 // The new object may have been created if an error is returned
 func (o *FsObjectDropbox) Update(in io.Reader, modTime time.Time, size int64) error {
-	rc := &readCloser{in: in}
+	// Calculate md5sum as we upload it
+	hash := md5.New()
+	rc := &readCloser{in: io.TeeReader(in, hash)}
 	entry, err := o.dropbox.db.UploadByChunk(rc, uploadChunkSize, o.remotePath(), true, "")
 	if err != nil {
 		return fmt.Errorf("Upload failed: %s", err)
 	}
-	o.setMetaData(entry)
-	return nil
+	o.setMetadataFromEntry(entry)
+
+	md5sum := fmt.Sprintf("%x", hash.Sum(nil))
+	return o.setModTimeAndMd5sum(modTime, md5sum)
 }
 
 // Remove an object