file handler directly read from volume servers

this mostly works fine now!

next: need to cache files to local disk

weed/filesys/filehandle.go

@@ -11,6 +11,9 @@ import (
 	"bytes"
 	"github.com/chrislusf/seaweedfs/weed/operation"
 	"time"
+	"strings"
+	"sync"
+	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
 type FileHandle struct {
@@ -33,46 +36,94 @@ type FileHandle struct {
 }
 
 var _ = fs.Handle(&FileHandle{})
-var _ = fs.HandleReadAller(&FileHandle{})
-// var _ = fs.HandleReader(&FileHandle{})
+// var _ = fs.HandleReadAller(&FileHandle{})
+var _ = fs.HandleReader(&FileHandle{})
 var _ = fs.HandleFlusher(&FileHandle{})
 var _ = fs.HandleWriter(&FileHandle{})
 var _ = fs.HandleReleaser(&FileHandle{})
 
-func (fh *FileHandle) ReadAll(ctx context.Context) (content []byte, err error) {
+func (fh *FileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
 
-	glog.V(3).Infof("%v/%v read all fh ", fh.dirPath, fh.name)
+	glog.V(3).Infof("%v/%v read fh: [%d,%d)", fh.dirPath, fh.name, req.Offset, req.Offset+int64(req.Size))
 
 	if len(fh.Chunks) == 0 {
 		glog.V(0).Infof("empty fh %v/%v", fh.dirPath, fh.name)
-		return
+		return fmt.Errorf("empty file %v/%v", fh.dirPath, fh.name)
 	}
 
-	err = fh.wfs.withFilerClient(func(client filer_pb.SeaweedFilerClient) error {
+	buff := make([]byte, req.Size)
 
-		// FIXME: need to either use Read() or implement differently
-		chunks, _ := filer2.CompactFileChunks(fh.Chunks)
-		glog.V(1).Infof("read fh %v/%v %d/%d chunks", fh.dirPath, fh.name, len(chunks), len(fh.Chunks))
-		for i, chunk := range chunks {
-			glog.V(1).Infof("read fh %v/%v %d/%d chunk %s [%d,%d)", fh.dirPath, fh.name, i, len(chunks), chunk.FileId, chunk.Offset, chunk.Offset+int64(chunk.Size))
-		}
-		request := &filer_pb.GetFileContentRequest{
-			FileId: chunks[0].FileId,
-		}
+	chunkViews := filer2.ReadFromChunks(fh.Chunks, req.Offset, req.Size)
 
-		glog.V(1).Infof("read fh content %d chunk %s [%d,%d): %v", len(chunks),
-			chunks[0].FileId, chunks[0].Offset, chunks[0].Offset+int64(chunks[0].Size), request)
-		resp, err := client.GetFileContent(ctx, request)
+	var vids []string
+	for _, chunkView := range chunkViews {
+		vids = append(vids, volumeId(chunkView.FileId))
+	}
+
+	vid2Locations := make(map[string]*filer_pb.Locations)
+
+	err := fh.wfs.withFilerClient(func(client filer_pb.SeaweedFilerClient) error {
+
+		glog.V(4).Infof("read fh lookup volume id locations: %v", vids)
+		resp, err := client.LookupVolume(ctx, &filer_pb.LookupVolumeRequest{
+			VolumeIds: vids,
+		})
 		if err != nil {
 			return err
 		}
 
-		content = resp.Content
+		vid2Locations = resp.LocationsMap
 
 		return nil
 	})
 
-	return content, err
+	if err != nil {
+		glog.V(3).Infof("%v/%v read fh lookup volume ids: %v", fh.dirPath, fh.name, err)
+		return fmt.Errorf("failed to lookup volume ids %v: %v", vids, err)
+	}
+
+	var totalRead int64
+	var wg sync.WaitGroup
+	for _, chunkView := range chunkViews {
+		wg.Add(1)
+		go func(chunkView *filer2.ChunkView) {
+			defer wg.Done()
+
+			glog.V(3).Infof("read fh reading chunk: %+v", chunkView)
+
+			locations := vid2Locations[volumeId(chunkView.FileId)]
+			if locations == nil || len(locations.Locations) == 0 {
+				glog.V(0).Infof("failed to locate %s", chunkView.FileId)
+				err = fmt.Errorf("failed to locate %s", chunkView.FileId)
+				return
+			}
+
+			var n int64
+			n, err = util.ReadUrl(
+				fmt.Sprintf("http://%s/%s", locations.Locations[0].Url, chunkView.FileId),
+				chunkView.Offset,
+				int(chunkView.Size),
+				buff[chunkView.LogicOffset-req.Offset:chunkView.LogicOffset-req.Offset+int64(chunkView.Size)])
+
+			if err != nil {
+
+				glog.V(0).Infof("%v/%v read http://%s/%v %v bytes: %v", fh.dirPath, fh.name, locations.Locations[0].Url, chunkView.FileId, n, err)
+
+				err = fmt.Errorf("failed to read http://%s/%s: %v",
+					locations.Locations[0].Url, chunkView.FileId, err)
+				return
+			}
+
+			glog.V(3).Infof("read fh read %d bytes: %+v", n, chunkView)
+			totalRead += n
+
+		}(chunkView)
+	}
+	wg.Wait()
+
+	resp.Data = buff[:totalRead]
+
+	return err
 }
 
 // Write to the file handle
@@ -179,3 +230,11 @@ func (fh *FileHandle) Flush(ctx context.Context, req *fuse.FlushRequest) error {
 
 	return err
 }
+
+func volumeId(fileId string) string {
+	lastCommaIndex := strings.LastIndex(fileId, ",")
+	if lastCommaIndex > 0 {
+		return fileId[:lastCommaIndex]
+	}
+	return fileId
+}