package topology import ( "code.google.com/p/weed-fs/go/storage" "errors" "fmt" "math/rand" ) type VolumeLayout struct { repType storage.ReplicationType vid2location map[storage.VolumeId]*VolumeLocationList writables []storage.VolumeId // transient array of writable volume id pulse int64 volumeSizeLimit uint64 } func NewVolumeLayout(repType storage.ReplicationType, volumeSizeLimit uint64, pulse int64) *VolumeLayout { return &VolumeLayout{ repType: repType, vid2location: make(map[storage.VolumeId]*VolumeLocationList), writables: *new([]storage.VolumeId), pulse: pulse, volumeSizeLimit: volumeSizeLimit, } } func (vl *VolumeLayout) RegisterVolume(v *storage.VolumeInfo, dn *DataNode) { if _, ok := vl.vid2location[v.Id]; !ok { vl.vid2location[v.Id] = NewVolumeLocationList() } if vl.vid2location[v.Id].Add(dn) { if len(vl.vid2location[v.Id].list) == v.RepType.GetCopyCount() { if vl.isWritable(v) { vl.writables = append(vl.writables, v.Id) } } } } func (vl *VolumeLayout) isWritable(v *storage.VolumeInfo) bool { return uint64(v.Size) < vl.volumeSizeLimit && v.Version == storage.CurrentVersion } func (vl *VolumeLayout) Lookup(vid storage.VolumeId) []*DataNode { if location := vl.vid2location[vid]; location != nil { return location.list } return nil } func (vl *VolumeLayout) PickForWrite(count int) (*storage.VolumeId, int, *VolumeLocationList, error) { len_writers := len(vl.writables) if len_writers <= 0 { fmt.Println("No more writable volumes!") return nil, 0, nil, errors.New("No more writable volumes!") } vid := vl.writables[rand.Intn(len_writers)] locationList := vl.vid2location[vid] if locationList != nil { return &vid, count, locationList, nil } return nil, 0, nil, errors.New("Strangely vid " + vid.String() + " is on no machine!") } func (vl *VolumeLayout) GetActiveVolumeCount() int { return len(vl.writables) } func (vl *VolumeLayout) removeFromWritable(vid storage.VolumeId) bool { for i, v := range vl.writables { if v == vid { fmt.Println("Volume", vid, "becomes unwritable") vl.writables = append(vl.writables[:i], vl.writables[i+1:]...) return true } } return false } func (vl *VolumeLayout) setVolumeWritable(vid storage.VolumeId) bool { for _, v := range vl.writables { if v == vid { return false } } fmt.Println("Volume", vid, "becomes writable") vl.writables = append(vl.writables, vid) return true } func (vl *VolumeLayout) SetVolumeUnavailable(dn *DataNode, vid storage.VolumeId) bool { if vl.vid2location[vid].Remove(dn) { if vl.vid2location[vid].Length() < vl.repType.GetCopyCount() { fmt.Println("Volume", vid, "has", vl.vid2location[vid].Length(), "replica, less than required", vl.repType.GetCopyCount()) return vl.removeFromWritable(vid) } } return false } func (vl *VolumeLayout) SetVolumeAvailable(dn *DataNode, vid storage.VolumeId) bool { if vl.vid2location[vid].Add(dn) { if vl.vid2location[vid].Length() >= vl.repType.GetCopyCount() { return vl.setVolumeWritable(vid) } } return false } func (vl *VolumeLayout) SetVolumeCapacityFull(vid storage.VolumeId) bool { return vl.removeFromWritable(vid) } func (vl *VolumeLayout) ToMap() interface{} { m := make(map[string]interface{}) m["replication"] = vl.repType.String() m["writables"] = vl.writables //m["locations"] = vl.vid2location return m }