func GetHostID(conn client.Connection, ip string) (string, error) {
leader := zzk.NewHostLeader(conn, "", "", vippath(ip))
return zzk.GetHostID(leader)
}
// Spawn implements zzk.Listener
func (l *VirtualIPListener) Spawn(shutdown <-chan interface{}, ip string) {
// ensure that the retry sentinel has good initial state
if l.retry == nil {
l.retry = make(map[string]int)
}
if _, ok := l.retry[ip]; !ok {
l.retry[ip] = maxRetries
}
// Check if this ip has exceeded the number of retries for this host
if l.retry[ip] > maxRetries {
glog.Warningf("Throttling acquisition of %s for %s", ip, l.hostID)
select {
case <-time.After(waitTimeout):
case <-shutdown:
return
}
}
glog.V(2).Infof("Host %s waiting to acquire virtual ip %s", l.hostID, ip)
// Try to take lead on the path
leader := zzk.NewHostLeader(l.conn, l.hostID, "", l.GetPath(ip))
_, err := leader.TakeLead()
if err != nil {
glog.Errorf("Error while trying to acquire a lock for %s: %s", ip, err)
return
}
defer l.stopInstances(ip)
defer leader.ReleaseLead()
select {
case <-shutdown:
return
default:
}
// Check if the path still exists
if exists, err := zzk.PathExists(l.conn, l.GetPath(ip)); err != nil {
glog.Errorf("Error while checking ip %s: %s", ip, err)
return
} else if !exists {
return
}
index := l.getIndex()
for {
var vip pool.VirtualIP
event, err := l.conn.GetW(l.GetPath(ip), &VirtualIPNode{VirtualIP: &vip})
if err == client.ErrEmptyNode {
glog.Errorf("Deleting empty node for ip %s", ip)
RemoveVirtualIP(l.conn, ip)
return
} else if err != nil {
glog.Errorf("Could not load virtual ip %s: %s", ip, err)
return
}
glog.V(2).Infof("Host %s binding to %s", l.hostID, ip)
rebind, err := l.bind(&vip, index)
if err != nil {
glog.Errorf("Could not bind to virtual ip %s: %s", ip, err)
l.retry[ip]++
return
}
if l.retry[ip] > 0 {
l.retry[ip]--
}
select {
case e := <-event:
// If the virtual ip is changed, you need to update the bindings
if err := l.unbind(ip); err != nil {
glog.Errorf("Could not unbind to virtual ip %s: %s", ip, err)
return
}
if e.Type == client.EventNodeDeleted {
return
}
glog.V(4).Infof("virtual ip listener for %s receieved event: %v", ip, e)
case <-rebind:
// If the primary virtual IP is removed, all other virtual IPs on
// that subnet are removed. This is in place to restore the
// virtual IPs that were removed soley by the removal of the
// primary virtual IP.
glog.V(2).Infof("Host %s rebinding to %s", l.hostID, ip)
case <-shutdown:
if err := l.unbind(ip); err != nil {
glog.Errorf("Could not unbind to virtual ip %s: %s", ip, err)
}
return
}
}
}