package consul import ( "net" "strings" "github.com/hashicorp/serf/serf" ) const ( // StatusReap is used to update the status of a node if we // are handling a EventMemberReap StatusReap = serf.MemberStatus(-1) // userEventPrefix is pre-pended to a user event to distinguish it userEventPrefix = "consul:event:" ) // userEventName computes the name of a user event func userEventName(name string) string { return userEventPrefix + name } // isUserEvent checks if a serf event is a user event func isUserEvent(name string) bool { return strings.HasPrefix(name, userEventPrefix) } // rawUserEventName is used to get the raw user event name func rawUserEventName(name string) string { return strings.TrimPrefix(name, userEventPrefix) } // lanEventHandler is used to handle events from the lan Serf cluster func (s *Server) lanEventHandler() { for { select { case e := <-s.eventChLAN: switch e.EventType() { case serf.EventMemberJoin: s.nodeJoin(e.(serf.MemberEvent), false) s.localMemberEvent(e.(serf.MemberEvent)) case serf.EventMemberLeave: fallthrough case serf.EventMemberFailed: s.nodeFailed(e.(serf.MemberEvent), false) s.localMemberEvent(e.(serf.MemberEvent)) case serf.EventMemberReap: s.localMemberEvent(e.(serf.MemberEvent)) case serf.EventUser: s.localEvent(e.(serf.UserEvent)) case serf.EventMemberUpdate: // Ignore case serf.EventQuery: // Ignore default: s.logger.Printf("[WARN] consul: unhandled LAN Serf Event: %#v", e) } case <-s.shutdownCh: return } } } // wanEventHandler is used to handle events from the wan Serf cluster func (s *Server) wanEventHandler() { for { select { case e := <-s.eventChWAN: switch e.EventType() { case serf.EventMemberJoin: s.nodeJoin(e.(serf.MemberEvent), true) case serf.EventMemberLeave: fallthrough case serf.EventMemberFailed: s.nodeFailed(e.(serf.MemberEvent), true) case serf.EventMemberUpdate: // Ignore case serf.EventMemberReap: // Ignore case serf.EventUser: case serf.EventQuery: // Ignore default: s.logger.Printf("[WARN] consul: unhandled WAN Serf Event: %#v", e) } case <-s.shutdownCh: return } } } // localMemberEvent is used to reconcile Serf events with the strongly // consistent store if we are the current leader func (s *Server) localMemberEvent(me serf.MemberEvent) { // Do nothing if we are not the leader if !s.IsLeader() { return } // Check if this is a reap event isReap := me.EventType() == serf.EventMemberReap // Queue the members for reconciliation for _, m := range me.Members { // Change the status if this is a reap event if isReap { m.Status = StatusReap } select { case s.reconcileCh <- m: default: } } } // localEvent is called when we receive an event on the local Serf func (s *Server) localEvent(event serf.UserEvent) { // Handle only consul events if !strings.HasPrefix(event.Name, "consul:") { return } switch name := event.Name; { case name == newLeaderEvent: s.logger.Printf("[INFO] consul: New leader elected: %s", event.Payload) // Trigger the callback if s.config.ServerUp != nil { s.config.ServerUp() } case isUserEvent(name): event.Name = rawUserEventName(name) s.logger.Printf("[DEBUG] consul: user event: %s", event.Name) // Trigger the callback if s.config.UserEventHandler != nil { s.config.UserEventHandler(event) } default: s.logger.Printf("[WARN] consul: Unhandled local event: %v", event) } } // nodeJoin is used to handle join events on the both serf clusters func (s *Server) nodeJoin(me serf.MemberEvent, wan bool) { for _, m := range me.Members { ok, parts := isConsulServer(m) if !ok { if wan { s.logger.Printf("[WARN] consul: non-server in WAN pool: %s", m.Name) } continue } s.logger.Printf("[INFO] consul: adding server %s", parts) // Check if this server is known found := false s.remoteLock.Lock() existing := s.remoteConsuls[parts.Datacenter] for idx, e := range existing { if e.Name == parts.Name { existing[idx] = parts found = true break } } // Add ot the list if not known if !found { s.remoteConsuls[parts.Datacenter] = append(existing, parts) } s.remoteLock.Unlock() // Add to the local list as well if !wan && parts.Datacenter == s.config.Datacenter { s.localLock.Lock() s.localConsuls[parts.Addr.String()] = parts s.localLock.Unlock() } // If we still expecting to bootstrap, may need to handle this if s.config.BootstrapExpect != 0 { s.maybeBootstrap() } } } // maybeBootsrap is used to handle bootstrapping when a new consul server joins func (s *Server) maybeBootstrap() { index, err := s.raftStore.LastIndex() if err != nil { s.logger.Printf("[ERR] consul: failed to read last raft index: %v", err) return } // Bootstrap can only be done if there are no committed logs, // remove our expectations of bootstrapping if index != 0 { s.config.BootstrapExpect = 0 return } // Scan for all the known servers members := s.serfLAN.Members() addrs := make([]net.Addr, 0) for _, member := range members { valid, p := isConsulServer(member) if !valid { continue } if p.Datacenter != s.config.Datacenter { s.logger.Printf("[ERR] consul: Member %v has a conflicting datacenter, ignoring", member) continue } if p.Expect != 0 && p.Expect != s.config.BootstrapExpect { s.logger.Printf("[ERR] consul: Member %v has a conflicting expect value. All nodes should expect the same number.", member) return } if p.Bootstrap { s.logger.Printf("[ERR] consul: Member %v has bootstrap mode. Expect disabled.", member) return } addrs = append(addrs, &net.TCPAddr{IP: member.Addr, Port: p.Port}) } // Skip if we haven't met the minimum expect count if len(addrs) < s.config.BootstrapExpect { return } // Update the peer set s.logger.Printf("[INFO] consul: Attempting bootstrap with nodes: %v", addrs) if err := s.raft.SetPeers(addrs).Error(); err != nil { s.logger.Printf("[ERR] consul: failed to bootstrap peers: %v", err) } // Bootstrapping comlete, don't enter this again s.config.BootstrapExpect = 0 } // nodeFailed is used to handle fail events on both the serf clustes func (s *Server) nodeFailed(me serf.MemberEvent, wan bool) { for _, m := range me.Members { ok, parts := isConsulServer(m) if !ok { continue } s.logger.Printf("[INFO] consul: removing server %s", parts) // Remove the server if known s.remoteLock.Lock() existing := s.remoteConsuls[parts.Datacenter] n := len(existing) for i := 0; i < n; i++ { if existing[i].Name == parts.Name { existing[i], existing[n-1] = existing[n-1], nil existing = existing[:n-1] n-- break } } // Trim the list if all known consuls are dead if n == 0 { delete(s.remoteConsuls, parts.Datacenter) } else { s.remoteConsuls[parts.Datacenter] = existing } s.remoteLock.Unlock() // Remove from the local list as well if !wan { s.localLock.Lock() delete(s.localConsuls, parts.Addr.String()) s.localLock.Unlock() } } }