// Join a server to the cluster
func (c *JoinCommandV1) Apply(context raft.Context) (interface{}, error) {
ps, _ := context.Server().Context().(*PeerServer)
b := make([]byte, 8)
binary.PutUvarint(b, context.CommitIndex())
// Make sure we're not getting a cached value from the registry.
ps.registry.Invalidate(c.Name)
// Check if the join command is from a previous peer, who lost all its previous log.
if _, ok := ps.registry.ClientURL(c.Name); ok {
return b, nil
}
// Check peer number in the cluster
if ps.registry.PeerCount() >= ps.ClusterConfig().ActiveSize {
log.Debug("Reject join request from ", c.Name)
return []byte{0}, etcdErr.NewError(etcdErr.EcodeNoMorePeer, "", context.CommitIndex())
}
// Add to shared peer registry.
ps.registry.RegisterPeer(c.Name, c.RaftURL, c.EtcdURL)
// Add peer in raft
err := context.Server().AddPeer(c.Name, "")
// Add peer stats
if c.Name != ps.RaftServer().Name() {
ps.followersStats.Followers[c.Name] = &raftFollowerStats{}
ps.followersStats.Followers[c.Name].Latency.Minimum = 1 << 63
}
return b, err
}
// Get the key
func (c *GetCommand) Apply(context raft.Context) (interface{}, error) {
s, _ := context.Server().StateMachine().(store.Store)
e, err := s.Get(c.Key, c.Recursive, c.Sorted)
if err != nil {
log.Debug(err)
return nil, err
}
return e, nil
}
// Set the key-value pair if the current value of the key equals to the given prevValue
func (c *CompareAndSwapCommand) Apply(context raft.Context) (interface{}, error) {
s, _ := context.Server().StateMachine().(store.Store)
e, err := s.CompareAndSwap(c.Key, c.PrevValue, c.PrevIndex, c.Value, c.ExpireTime)
if err != nil {
log.Debug(err)
return nil, err
}
return e, nil
}
// Create node
func (c *CreateCommand) Apply(context raft.Context) (interface{}, error) {
s, _ := context.Server().StateMachine().(store.Store)
e, err := s.Create(c.Key, c.Dir, c.Value, c.Unique, c.ExpireTime)
if err != nil {
log.Debug(err)
return nil, err
}
return e, nil
}
// Create node
func (c *SetCommand) Apply(context raft.Context) (interface{}, error) {
s, _ := context.Server().StateMachine().(store.Store)
// create a new node or replace the old node.
e, err := s.Set(c.Key, c.Dir, c.Value, c.ExpireTime)
if err != nil {
log.Debug(err)
return nil, err
}
return e, nil
}
// applyJoin attempts to join a machine to the cluster.
func applyJoin(c *JoinCommand, context raft.Context) (uint64, error) {
ps, _ := context.Server().Context().(*PeerServer)
commitIndex := context.CommitIndex()
// Make sure we're not getting a cached value from the registry.
ps.registry.Invalidate(c.Name)
// Check if the join command is from a previous peer, who lost all its previous log.
if peerURL, ok := ps.registry.PeerURL(c.Name); ok {
// If previous node restarts with different peer URL,
// update its information.
if peerURL != c.RaftURL {
log.Infof("Rejoin with %v instead of %v from %v", c.RaftURL, peerURL, c.Name)
if err := updatePeerURL(c, ps); err != nil {
return 0, err
}
}
return commitIndex, nil
}
// Check if the join command adds an instance that collides with existing one on peer URL.
peerURLs := ps.registry.PeerURLs(ps.raftServer.Leader(), c.Name)
for _, peerURL := range peerURLs {
if peerURL == c.RaftURL {
log.Warnf("%v tries to join the cluster with existing URL %v", c.Name, c.EtcdURL)
return 0, etcdErr.NewError(etcdErr.EcodeExistingPeerAddr, c.EtcdURL, context.CommitIndex())
}
}
// Check peer number in the cluster
if ps.registry.Count() >= ps.ClusterConfig().ActiveSize {
log.Debug("Reject join request from ", c.Name)
return 0, etcdErr.NewError(etcdErr.EcodeNoMorePeer, "", context.CommitIndex())
}
// Add to shared peer registry.
ps.registry.Register(c.Name, c.RaftURL, c.EtcdURL)
// Add peer in raft
if err := context.Server().AddPeer(c.Name, ""); err != nil {
return 0, err
}
// Add peer stats
if c.Name != ps.RaftServer().Name() {
ps.followersStats.Followers[c.Name] = &raftFollowerStats{}
ps.followersStats.Followers[c.Name].Latency.Minimum = 1 << 63
}
return commitIndex, nil
}
// Delete the key
func (c *DeleteCommand) Apply(context raft.Context) (interface{}, error) {
s, _ := context.Server().StateMachine().(store.Store)
if c.Recursive {
// recursive implies dir
c.Dir = true
}
e, err := s.Delete(c.Key, c.Dir, c.Recursive)
if err != nil {
log.Debug(err)
return nil, err
}
return e, nil
}
// Apply attempts to join a machine to the cluster.
func (c *JoinCommandV2) Apply(context raft.Context) (interface{}, error) {
ps, _ := context.Server().Context().(*PeerServer)
var msg = joinMessageV2{
Mode: PeerMode,
CommitIndex: context.CommitIndex(),
}
// Make sure we're not getting a cached value from the registry.
ps.registry.Invalidate(c.Name)
// Check if the join command is from a previous peer, who lost all its previous log.
if _, ok := ps.registry.ClientURL(c.Name); ok {
return json.Marshal(msg)
}
// Check peer number in the cluster.
if ps.registry.PeerCount() >= ps.ClusterConfig().ActiveSize {
log.Debug("Join as proxy ", c.Name)
ps.registry.RegisterProxy(c.Name, c.PeerURL, c.ClientURL)
msg.Mode = ProxyMode
return json.Marshal(msg)
}
// Remove it as a proxy if it is one.
if ps.registry.ProxyExists(c.Name) {
ps.registry.UnregisterProxy(c.Name)
}
// Add to shared peer registry.
ps.registry.RegisterPeer(c.Name, c.PeerURL, c.ClientURL)
// Add peer in raft
if err := context.Server().AddPeer(c.Name, ""); err != nil {
b, _ := json.Marshal(msg)
return b, err
}
// Add peer stats
if c.Name != ps.RaftServer().Name() {
ps.followersStats.Followers[c.Name] = &raftFollowerStats{}
ps.followersStats.Followers[c.Name].Latency.Minimum = 1 << 63
}
return json.Marshal(msg)
}
// Apply executes the command.
func (c *DemoteCommand) Apply(context raft.Context) (interface{}, error) {
ps, _ := context.Server().Context().(*PeerServer)
// Ignore this command if there is no peer.
if !ps.registry.PeerExists(c.Name) {
return nil, fmt.Errorf("peer does not exist: %s", c.Name)
}
// Save URLs.
clientURL, _ := ps.registry.ClientURL(c.Name)
peerURL, _ := ps.registry.PeerURL(c.Name)
// Remove node from the shared registry.
err := ps.registry.UnregisterPeer(c.Name)
if err != nil {
log.Debugf("Demote peer %s: Error while unregistering (%v)", c.Name, err)
return nil, err
}
// Delete from stats
delete(ps.followersStats.Followers, c.Name)
// Remove peer in raft
err = context.Server().RemovePeer(c.Name)
if err != nil {
log.Debugf("Demote peer %s: (%v)", c.Name, err)
return nil, err
}
// Register node as a standby.
ps.registry.RegisterStandby(c.Name, peerURL, clientURL)
// Update mode if this change applies to this server.
if c.Name == ps.Config.Name {
log.Infof("Demote peer %s: Set mode to standby with %s", c.Name, ps.server.Leader())
ps.standbyPeerURL, _ = ps.registry.PeerURL(ps.server.Leader())
go ps.setMode(StandbyMode)
}
return nil, nil
}
// Remove a server from the cluster
func (c *RemoveCommandV1) Apply(context raft.Context) (interface{}, error) {
ps, _ := context.Server().Context().(*PeerServer)
// If this is a standby then remove it and exit.
if ps.registry.StandbyExists(c.Name) {
return []byte{0}, ps.registry.UnregisterStandby(c.Name)
}
// Remove node from the shared registry.
err := ps.registry.UnregisterPeer(c.Name)
// Delete from stats
delete(ps.followersStats.Followers, c.Name)
if err != nil {
log.Debugf("Error while unregistering: %s (%v)", c.Name, err)
return []byte{0}, err
}
// Remove peer in raft
err = context.Server().RemovePeer(c.Name)
if err != nil {
log.Debugf("Unable to remove peer: %s (%v)", c.Name, err)
return []byte{0}, err
}
if c.Name == context.Server().Name() {
// the removed node is this node
// if the node is not replaying the previous logs
// and the node has sent out a join request in this
// start. It is sure that this node received a new remove
// command and need to be removed
if context.CommitIndex() > ps.joinIndex && ps.joinIndex != 0 {
log.Debugf("server [%s] is removed", context.Server().Name())
os.Exit(0)
} else {
// else ignore remove
log.Debugf("ignore previous remove command.")
}
}
b := make([]byte, 8)
binary.PutUvarint(b, context.CommitIndex())
return b, err
}
// Apply removes the given machine from the cluster.
func (c *RemoveCommandV2) Apply(context raft.Context) (interface{}, error) {
ps, _ := context.Server().Context().(*PeerServer)
ret, _ := json.Marshal(removeMessageV2{CommitIndex: context.CommitIndex()})
// If this is a proxy then remove it and exit.
if ps.registry.ProxyExists(c.Name) {
if err := ps.registry.UnregisterProxy(c.Name); err != nil {
return nil, err
}
return ret, nil
}
// Remove node from the shared registry.
err := ps.registry.UnregisterPeer(c.Name)
// Delete from stats
delete(ps.followersStats.Followers, c.Name)
if err != nil {
log.Debugf("Error while unregistering: %s (%v)", c.Name, err)
return nil, err
}
// Remove peer in raft
if err := context.Server().RemovePeer(c.Name); err != nil {
log.Debugf("Unable to remove peer: %s (%v)", c.Name, err)
return nil, err
}
if c.Name == context.Server().Name() {
// the removed node is this node
// if the node is not replaying the previous logs
// and the node has sent out a join request in this
// start. It is sure that this node received a new remove
// command and need to be removed
if context.CommitIndex() > ps.joinIndex && ps.joinIndex != 0 {
log.Debugf("server [%s] is removed", context.Server().Name())
os.Exit(0)
} else {
// else ignore remove
log.Debugf("ignore previous remove command.")
}
}
return ret, nil
}
// applyRemove removes the given machine from the cluster.
func applyRemove(c *RemoveCommand, context raft.Context) (uint64, error) {
ps, _ := context.Server().Context().(*PeerServer)
commitIndex := context.CommitIndex()
// Remove node from the shared registry.
err := ps.registry.Unregister(c.Name)
// Delete from stats
delete(ps.followersStats.Followers, c.Name)
if err != nil {
log.Debugf("Error while unregistering: %s (%v)", c.Name, err)
return 0, err
}
// Remove peer in raft
if err := context.Server().RemovePeer(c.Name); err != nil {
log.Debugf("Unable to remove peer: %s (%v)", c.Name, err)
return 0, err
}
if c.Name == context.Server().Name() {
// the removed node is this node
// if the node is not replaying the previous logs
// and the node has sent out a join request in this
// start. It is sure that this node received a new remove
// command and need to be removed
if context.CommitIndex() > ps.joinIndex && ps.joinIndex != 0 {
log.Debugf("server [%s] is removed", context.Server().Name())
ps.asyncRemove()
} else {
// else ignore remove
log.Debugf("ignore previous remove command.")
ps.removedInLog = true
}
}
return commitIndex, nil
}
// Apply updates the cluster configuration.
func (c *SetClusterConfigCommand) Apply(context raft.Context) (interface{}, error) {
ps, _ := context.Server().Context().(*PeerServer)
ps.SetClusterConfig(c.Config)
return nil, nil
}
func (c SyncCommand) Apply(context raft.Context) (interface{}, error) {
s, _ := context.Server().StateMachine().(store.Store)
s.DeleteExpiredKeys(c.Time)
return nil, nil
}
// Apply attempts to join a machine to the cluster.
func (c *JoinCommandV2) Apply(context raft.Context) (interface{}, error) {
ps, _ := context.Server().Context().(*PeerServer)
var msg = joinMessageV2{
Mode: PeerMode,
CommitIndex: context.CommitIndex(),
}
// Make sure we're not getting a cached value from the registry.
ps.registry.Invalidate(c.Name)
// Check if the join command is from a previous peer, who lost all its previous log.
if peerURL, ok := ps.registry.PeerURL(c.Name); ok {
// If previous node restarts with different peer URL,
// update its information.
if peerURL != c.PeerURL {
log.Infof("Rejoin with %v instead of %v from %v", c.PeerURL, peerURL, c.Name)
if err := c.updatePeerURL(ps); err != nil {
return []byte{0}, err
}
}
return json.Marshal(msg)
}
// Check if the join command adds an instance that collides with existing one on peer URL.
peerURLs := ps.registry.PeerURLs(ps.raftServer.Leader(), c.Name)
for _, peerURL := range peerURLs {
if peerURL == c.PeerURL {
log.Warnf("%v tries to join the cluster with existing URL %v", c.Name, c.PeerURL)
return []byte{0}, etcdErr.NewError(etcdErr.EcodeExistingPeerAddr, c.PeerURL, context.CommitIndex())
}
}
// Check peer number in the cluster.
if ps.registry.PeerCount() >= ps.ClusterConfig().ActiveSize {
log.Debug("Join as standby ", c.Name)
ps.registry.RegisterStandby(c.Name, c.PeerURL, c.ClientURL)
msg.Mode = StandbyMode
return json.Marshal(msg)
}
// Remove it as a standby if it is one.
if ps.registry.StandbyExists(c.Name) {
ps.registry.UnregisterStandby(c.Name)
}
// Add to shared peer registry.
ps.registry.RegisterPeer(c.Name, c.PeerURL, c.ClientURL)
// Add peer in raft
if err := context.Server().AddPeer(c.Name, ""); err != nil {
b, _ := json.Marshal(msg)
return b, err
}
// Add peer stats
if c.Name != ps.RaftServer().Name() {
ps.followersStats.Followers[c.Name] = &raftFollowerStats{}
ps.followersStats.Followers[c.Name].Latency.Minimum = 1 << 63
}
return json.Marshal(msg)
}