func readDatabase() (Database, error) {
kvdb := kvdb.Instance()
db := Database{
Status: api.Status_STATUS_INIT,
NodeEntries: make(map[string]NodeEntry),
}
kv, err := kvdb.Get(ClusterDBKey)
if err != nil && !strings.Contains(err.Error(), "Key not found") {
dlog.Warnln("Warning, could not read cluster database")
return db, err
}
if kv == nil || bytes.Compare(kv.Value, []byte("{}")) == 0 {
dlog.Infoln("Cluster is uninitialized...")
return db, nil
}
if err := json.Unmarshal(kv.Value, &db); err != nil {
dlog.Warnln("Fatal, Could not parse cluster database ", kv)
return db, err
}
return db, nil
}
func writeDatabase(db *Database) error {
kvdb := kvdb.Instance()
b, err := json.Marshal(db)
if err != nil {
dlog.Warnf("Fatal, Could not marshal cluster database to JSON: %v", err)
return err
}
if _, err := kvdb.Put(ClusterDBKey, b, 0); err != nil {
dlog.Warnf("Fatal, Could not marshal cluster database to JSON: %v", err)
return err
}
dlog.Infoln("Cluster database updated.")
return nil
}
func (c *ClusterManager) Start() error {
dlog.Infoln("Cluster manager starting...")
c.gEnabled = true
c.selfNode = api.Node{}
c.selfNode.GenNumber = uint64(time.Now().UnixNano())
c.selfNode.Id = c.config.NodeId
c.selfNode.Status = api.Status_STATUS_OK
c.selfNode.MgmtIp, c.selfNode.DataIp, _ = ExternalIp(&c.config)
c.selfNode.NodeData = make(map[string]interface{})
c.system = systemutils.New()
// Start the gossip protocol.
// XXX Make the port configurable.
gob.Register(api.Node{})
c.gossip = gossip.New("0.0.0.0:9002", types.NodeId(c.config.NodeId),
c.selfNode.GenNumber)
c.gossip.SetGossipInterval(2 * time.Second)
kvdb := kvdb.Instance()
kvlock, err := kvdb.Lock(clusterLockKey, 60)
if err != nil {
dlog.Panicln("Fatal, Unable to obtain cluster lock.", err)
}
defer kvdb.Unlock(kvlock)
db, err := readDatabase()
if err != nil {
dlog.Panicln(err)
}
// Cluster database max size... 0 if unlimited.
c.size = db.Size
if db.Status == api.Status_STATUS_INIT {
dlog.Infoln("Will initialize a new cluster.")
c.status = api.Status_STATUS_OK
db.Status = api.Status_STATUS_OK
self, _ := c.initNode(&db)
err = c.initCluster(&db, self, false)
if err != nil {
dlog.Errorln("Failed to initialize the cluster.", err)
return err
}
// Update the new state of the cluster in the KV Database
err := writeDatabase(&db)
if err != nil {
dlog.Errorln("Failed to save the database.", err)
return err
}
} else if db.Status&api.Status_STATUS_OK > 0 {
dlog.Infoln("Cluster state is OK... Joining the cluster.")
c.status = api.Status_STATUS_OK
self, exist := c.initNode(&db)
err = c.joinCluster(&db, self, exist)
if err != nil {
dlog.Errorln("Failed to join cluster.", err)
return err
}
err := writeDatabase(&db)
if err != nil {
return err
}
} else {
return errors.New("Fatal, Cluster is in an unexpected state.")
}
// Start heartbeating to other nodes.
go c.startHeartBeat()
go c.updateClusterStatus()
kvdb.WatchKey(ClusterDBKey, 0, nil, c.watchDB)
return nil
}