fixing help message printing

weed-fs/src/pkg/directory/volume_mapping.go

@@ -7,36 +7,38 @@ import (
 	"pkg/sequence"
 	"pkg/storage"
 	"pkg/util"
-	"sync"
+	"time"
 )
 
 type Machine struct {
 	Volumes   []storage.VolumeInfo
 	Url       string //<server name/ip>[:port]
 	PublicUrl string
+	LastSeen  int64 // unix time in seconds
 }
 
 type Mapper struct {
-	volumeLock    sync.Mutex
-	Machines      map[string]*Machine
-	vid2machineId map[storage.VolumeId]*Machine //machineId is +1 of the index of []*Machine, to detect not found entries
-	Writers       []storage.VolumeId            // transient array of Writers volume id
+	Machines    map[string]*Machine
+	vid2machine map[storage.VolumeId]*Machine
+	Writers     []storage.VolumeId // transient array of Writers volume id
+	pulse       int64
 
 	volumeSizeLimit uint64
 
 	sequence sequence.Sequencer
 }
 
-func NewMachine(server, publicUrl string, volumes []storage.VolumeInfo) *Machine {
-	return &Machine{Url: server, PublicUrl: publicUrl, Volumes: volumes}
+func NewMachine(server, publicUrl string, volumes []storage.VolumeInfo, lastSeen int64) *Machine {
+	return &Machine{Url: server, PublicUrl: publicUrl, Volumes: volumes, LastSeen: lastSeen}
 }
 
-func NewMapper(dirname string, filename string, volumeSizeLimit uint64) (m *Mapper) {
+func NewMapper(dirname string, filename string, volumeSizeLimit uint64, pulse int) (m *Mapper) {
 	m = &Mapper{}
-	m.vid2machineId = make(map[storage.VolumeId]*Machine)
+	m.vid2machine = make(map[storage.VolumeId]*Machine)
 	m.volumeSizeLimit = volumeSizeLimit
 	m.Writers = *new([]storage.VolumeId)
 	m.Machines = make(map[string]*Machine)
+	m.pulse = int64(pulse)
 
 	m.sequence = sequence.NewSequencer(dirname, filename)
 
@@ -49,7 +51,7 @@ func (m *Mapper) PickForWrite(c string) (string, int, *Machine, error) {
 		return "", 0, nil, errors.New("No more writable volumes!")
 	}
 	vid := m.Writers[rand.Intn(len_writers)]
-	machine := m.vid2machineId[vid]
+	machine := m.vid2machine[vid]
 	if machine != nil {
 		fileId, count := m.sequence.NextFileId(util.ParseInt(c, 1))
 		if count == 0 {
@@ -60,29 +62,39 @@ func (m *Mapper) PickForWrite(c string) (string, int, *Machine, error) {
 	return "", 0, nil, errors.New("Strangely vid " + vid.String() + " is on no machine!")
 }
 func (m *Mapper) Get(vid storage.VolumeId) (*Machine, error) {
-	machine := m.vid2machineId[vid]
+	machine := m.vid2machine[vid]
 	if machine == nil {
 		return nil, errors.New("invalid volume id " + vid.String())
 	}
 	return machine, nil
 }
 func (m *Mapper) Add(machine *Machine) {
-	//check existing machine, linearly
-	//log.Println("Adding machine", machine.Server.Url)
-	m.volumeLock.Lock()
 	m.Machines[machine.Url] = machine
-	m.volumeLock.Unlock()
-
-	//add to vid2machineId map, and Writers array
+	//add to vid2machine map, and Writers array
 	for _, v := range machine.Volumes {
-		m.vid2machineId[v.Id] = machine
+		m.vid2machine[v.Id] = machine
 	}
+	m.refreshWritableVolumes()
+}
+func (m *Mapper) StartRefreshWritableVolumes() {
+	go func() {
+		for {
+			m.refreshWritableVolumes()
+			time.Sleep(time.Duration(float32(m.pulse*1e3)*(1+rand.Float32())) * time.Millisecond)
+		}
+	}()
+}
+
+func (m *Mapper) refreshWritableVolumes() {
+	freshThreshHold := time.Now().Unix() - 5*m.pulse //5 times of sleep interval
 	//setting Writers, copy-on-write because of possible updating, this needs some future work!
 	var writers []storage.VolumeId
 	for _, machine_entry := range m.Machines {
-		for _, v := range machine_entry.Volumes {
-			if uint64(v.Size) < m.volumeSizeLimit {
-				writers = append(writers, v.Id)
+		if machine_entry.LastSeen > freshThreshHold {
+			for _, v := range machine_entry.Volumes {
+				if uint64(v.Size) < m.volumeSizeLimit {
+					writers = append(writers, v.Id)
+				}
 			}
 		}
 	}