seaweedfs/weed-fs/src/pkg/topology/topology.go

package topology

import (
	"errors"
	"math/rand"
	"pkg/directory"
	"pkg/sequence"
	"pkg/storage"
	"io/ioutil"
)

type Topology struct {
	NodeImpl

	//transient vid~servers mapping for each replication type
	replicaType2VolumeLayout []*VolumeLayout

	pulse int64

	volumeSizeLimit uint64

	sequence sequence.Sequencer

	chanDeadDataNodes      chan *DataNode
	chanRecoveredDataNodes chan *DataNode
	chanFullVolumes        chan *storage.VolumeInfo
	
	configuration *Configuration
}

func NewTopology(id string, confFile string, dirname string, filename string, volumeSizeLimit uint64, pulse int) *Topology {
	t := &Topology{}
	t.id = NodeId(id)
	t.nodeType = "Topology"
	t.NodeImpl.value = t
	t.children = make(map[NodeId]Node)
	t.replicaType2VolumeLayout = make([]*VolumeLayout, storage.LengthRelicationType)
	t.pulse = int64(pulse)
	t.volumeSizeLimit = volumeSizeLimit

	t.sequence = sequence.NewSequencer(dirname, filename)

	t.chanDeadDataNodes = make(chan *DataNode)
	t.chanRecoveredDataNodes = make(chan *DataNode)
	t.chanFullVolumes = make(chan *storage.VolumeInfo)

  t.loadConfiguration(confFile)
	
	return t
}

func (t *Topology) loadConfiguration(configurationFile string)error{
  b, e := ioutil.ReadFile(configurationFile);
  if e ==nil{
    t.configuration, e = NewConfiguration(b)
  }
  return e 
}

func (t *Topology) Lookup(vid storage.VolumeId) (*[]*DataNode) {
  for _, vl := range t.replicaType2VolumeLayout {
    if list := vl.Lookup(vid); list!=nil {
      return list
    }
  }
  return nil
}

func (t *Topology) RandomlyReserveOneVolume() (bool, *DataNode, *storage.VolumeId) {
	if t.FreeSpace() <= 0 {
		return false, nil, nil
	}
	vid := t.NextVolumeId()
	ret, node := t.ReserveOneVolume(rand.Intn(t.FreeSpace()), vid)
	return ret, node, &vid
}

func (t *Topology) RandomlyReserveOneVolumeExcept(except []Node) (bool, *DataNode, *storage.VolumeId) {
	freeSpace := t.FreeSpace()
	for _, node := range except {
		freeSpace -= node.FreeSpace()
	}
	if freeSpace <= 0 {
		return false, nil, nil
	}
	vid := t.NextVolumeId()
	ret, node := t.ReserveOneVolume(rand.Intn(freeSpace), vid)
	return ret, node, &vid
}

func (t *Topology) NextVolumeId() storage.VolumeId {
	vid := t.GetMaxVolumeId()
	return vid.Next()
}

func (t *Topology) PickForWrite(repType storage.ReplicationType, count int) (string, int, *DataNode, error) {
	replicationTypeIndex := repType.GetReplicationLevelIndex()
	if t.replicaType2VolumeLayout[replicationTypeIndex] == nil {
		t.replicaType2VolumeLayout[replicationTypeIndex] = NewVolumeLayout(repType, t.volumeSizeLimit, t.pulse)
	}
	vid, count, datanodes, err := t.replicaType2VolumeLayout[replicationTypeIndex].PickForWrite(count)
	if err != nil {
		return "", 0, nil, errors.New("No writable volumes avalable!")
	}
	fileId, count := t.sequence.NextFileId(count)
	return directory.NewFileId(*vid, fileId, rand.Uint32()).String(), count, datanodes.Head(), nil
}

func (t *Topology) GetVolumeLayout(repType storage.ReplicationType) *VolumeLayout {
	replicationTypeIndex := repType.GetReplicationLevelIndex()
	if t.replicaType2VolumeLayout[replicationTypeIndex] == nil {
		t.replicaType2VolumeLayout[replicationTypeIndex] = NewVolumeLayout(repType, t.volumeSizeLimit, t.pulse)
	}
	return t.replicaType2VolumeLayout[replicationTypeIndex]
}

func (t *Topology) RegisterVolumeLayout(v *storage.VolumeInfo, dn *DataNode) {
	t.GetVolumeLayout(v.RepType).RegisterVolume(v, dn)
}

func (t *Topology) RegisterVolumes(volumeInfos []storage.VolumeInfo, ip string, port int, publicUrl string, maxVolumeCount int) {
  dcName, rackName := t.configuration.Locate(ip)
	dc := t.GetOrCreateDataCenter(dcName)
	rack := dc.GetOrCreateRack(rackName)
	dn := rack.GetOrCreateDataNode(ip, port, publicUrl, maxVolumeCount)
	for _, v := range volumeInfos {
		dn.AddOrUpdateVolume(v)
		t.RegisterVolumeLayout(&v, dn)
	}
}

func (t *Topology) GetOrCreateDataCenter(dcName string) *DataCenter {
	for _, c := range t.Children() {
		dc := c.(*DataCenter)
		if string(dc.Id()) == dcName {
			return dc
		}
	}
	dc := NewDataCenter(dcName)
	t.LinkChildNode(dc)
	return dc
}

func (t *Topology) ToMap() interface{} {
	m := make(map[string]interface{})
  m["Max"] = t.GetMaxVolumeCount()
	m["Free"] = t.FreeSpace()
	var dcs []interface{}
	for _, c := range t.Children() {
		dc := c.(*DataCenter)
		dcs = append(dcs, dc.ToMap())
	}
	m["DataCenters"] = dcs
	var layouts []interface{}
	for _, layout := range t.replicaType2VolumeLayout {
		if layout != nil {
			layouts = append(layouts, layout.ToMap())
		}
	}
	m["layouts"] = layouts
	return m
}