seaweedfs/weed/server/volume_grpc_remote.go

package weed_server

import (
	"context"
	"fmt"
	"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
	"github.com/chrislusf/seaweedfs/weed/remote_storage"
	"github.com/chrislusf/seaweedfs/weed/storage/needle"
	"github.com/chrislusf/seaweedfs/weed/storage/types"
)

func (vs *VolumeServer) FetchAndWriteNeedle(ctx context.Context, req *volume_server_pb.FetchAndWriteNeedleRequest) (resp *volume_server_pb.FetchAndWriteNeedleResponse, err error) {
	resp = &volume_server_pb.FetchAndWriteNeedleResponse{}
	v := vs.store.GetVolume(needle.VolumeId(req.VolumeId))
	if v == nil {
		return nil, fmt.Errorf("not found volume id %d", req.VolumeId)
	}

	remoteConf := req.RemoteConf

	client, getClientErr := remote_storage.GetRemoteStorage(remoteConf)
	if getClientErr != nil {
		return nil, fmt.Errorf("get remote client: %v", getClientErr)
	}

	remoteStorageLocation := req.RemoteLocation

	data, ReadRemoteErr := client.ReadFile(remoteStorageLocation, req.Offset, req.Size)
	if ReadRemoteErr != nil {
		return nil, fmt.Errorf("read from remote %+v: %v", remoteStorageLocation, ReadRemoteErr)
	}

	n := new(needle.Needle)
	n.Id = types.NeedleId(req.NeedleId)
	n.Cookie = types.Cookie(req.Cookie)
	n.Data, n.DataSize = data, uint32(len(data))
	// copied from *Needle.prepareWriteBuffer()
	n.Size = 4 + types.Size(n.DataSize) + 1
	n.Checksum = needle.NewCRC(n.Data)
	if _, err = vs.store.WriteVolumeNeedle(v.Id, n, true, false); err != nil {
		return nil, fmt.Errorf("write needle %d size %d: %v", req.NeedleId, req.Size, err)
	}

	return resp, nil
}