func (fsm *FSM) Apply(l *raft.Log) interface{} {
// Skip all messages that are raft-related.
if l.Type != raft.LogCommand {
return nil
}
if err := fsm.ircstore.StoreLog(l); err != nil {
log.Panicf("Could not persist message in irclogs/: %v", err)
}
msg := types.NewRobustMessageFromBytes(l.Data)
log.Printf("Apply(msg.Type=%s)\n", msg.Type)
defer func() {
if msg.Type == types.RobustMessageOfDeath {
return
}
if r := recover(); r != nil {
// Panics in ircserver.ProcessMessage() are a problem, since
// they will bring down the entire raft cluster and you cannot
// bring up any raft node anymore without deleting the entire
// log.
//
// Therefore, when we panic, we invalidate the log entry in
// question before crashing. This doesn’t fix the underlying
// bug, i.e. an IRC message will then go unhandled, but it
// prevents RobustIRC from dying horribly in such a situation.
msg.Type = types.RobustMessageOfDeath
data, err := json.Marshal(msg)
if err != nil {
glog.Fatalf("Could not marshal message: %v", err)
}
l.Data = data
if err := fsm.store.StoreLog(l); err != nil {
glog.Fatalf("Could not store log while marking message as message of death: %v", err)
}
log.Printf("Marked %+v as message of death\n", l)
glog.Fatalf("%v", r)
}
}()
switch msg.Type {
case types.RobustMessageOfDeath:
// To prevent the message from being accepted again.
ircServer.UpdateLastClientMessageID(&msg)
log.Printf("Skipped message of death.\n")
case types.RobustCreateSession:
ircServer.CreateSession(msg.Id, msg.Data)
case types.RobustDeleteSession:
if _, err := ircServer.GetSession(msg.Session); err == nil {
// TODO(secure): overwrite QUIT messages for services with an faq entry explaining that they are not robust yet.
reply := ircServer.ProcessMessage(msg.Id, msg.Session, irc.ParseMessage("QUIT :"+string(msg.Data)))
ircServer.SendMessages(reply, msg.Session, msg.Id.Id)
}
case types.RobustIRCFromClient:
// Need to do this first, because ircserver.ProcessMessage could delete
// the session, e.g. by using KILL or QUIT.
if err := ircServer.UpdateLastClientMessageID(&msg); err != nil {
log.Printf("Error updating the last message for session: %v\n", err)
} else {
reply := ircServer.ProcessMessage(msg.Id, msg.Session, irc.ParseMessage(string(msg.Data)))
ircServer.SendMessages(reply, msg.Session, msg.Id.Id)
}
case types.RobustConfig:
newCfg, err := config.FromString(string(msg.Data))
if err != nil {
log.Printf("Skipping unexpectedly invalid configuration (%v)\n", err)
} else {
netConfig = newCfg
ircServer.Config = netConfig.IRC
}
}
appliedMessages.WithLabelValues(msg.Type.String()).Inc()
return nil
}
