//
// shared by Put and Append.
//
func (ck *Clerk) PutAppend(key string, value string, op string) {
ck.mu.Lock()
defer ck.mu.Unlock()
xid := nrand()
putReq := &PutAppendArgs{}
putRep := &PutAppendReply{}
putReq.Xid = xid
putReq.Value = value
putReq.Op = op
putReq.Key = key
tries := 0
for {
time.Sleep(100 * time.Millisecond)
tries = tries + 1
glog.Infoln(" Loop count", tries)
for index, _ := range ck.servers {
glog.Infoln(ck.uuid, "PutAppend Calling server ", index, " for request ", putReq.Op)
ret := call(ck.servers[index], "KVPaxos.PutAppend", putReq, putRep)
if ret {
//we got a response check if invalid response in which case try again
if putRep.Err != OK {
continue
}
return
} else {
glog.Warningln(ck.uuid, "RPC broke, retrying for a different server ", ck.servers)
continue
}
}
}
}
func ping(conn net.Conn) error {
select {
case pingAtCh <- 1:
glog.Infoln("Escort slave send ping!")
default:
// 没有收到上一次ping的pong，超时
glog.Warningln("Escort slave doesn't get pong!")
return new(PingTimeOutErr)
}
pingcmd := new(Packet)
pingcmd.Version = V1
pingcmd.Flags = FLAG_REQUEST
pingcmd.Length = 0
pingcmd.Sequence = 0
data, err := pingcmd.Encode()
_, err = conn.Write(data)
if err != nil {
glog.Errorf("[ERROR] %s", err.Error())
return err
}
return nil
}
//
// servers[] contains the ports of the set of
// servers that will cooperate via Paxos to
// form the fault-tolerant key/value service.
// me is the index of the current server in servers[].
//
func StartServer(servers []string, me int) *KVPaxos {
// Go's RPC library to marshall/unmarshall.
gob.Register(Op{})
kv := new(KVPaxos)
kv.me = me
kv.seenMap = make(map[int64]bool)
kv.kvData = make(map[string]string)
kv.toprocess = 1
rpcs := rpc.NewServer()
rpcs.Register(kv)
kv.px = paxos.Make(servers, me, rpcs)
os.Remove(servers[me])
l, e := net.Listen("unix", servers[me])
if e != nil {
glog.Fatal("listen error: ", e)
}
kv.l = l
go func() {
for kv.isdead() == false {
conn, err := kv.l.Accept()
if err == nil && kv.isdead() == false {
go rpcs.ServeConn(conn)
} else if err == nil {
conn.Close()
}
if err != nil && kv.isdead() == false {
glog.Warningln("KVPaxos(%v) accept: %v\n", me, err.Error())
kv.kill()
}
}
}()
return kv
}
//
// call() sends an RPC to the rpcname handler on server srv
// with arguments args, waits for the reply, and leaves the
// reply in reply. the reply argument should be a pointer
// to a reply structure.
//
// the return value is true if the server responded, and false
// if call() was not able to contact the server. in particular,
// tplys contents are only valid if call() returned true.
//
//
func call(srv string, name string, args interface{}, reply interface{}) bool {
c, err := rpc.Dial("unix", srv)
if err != nil {
err1 := err.(*net.OpError)
if err1.Err != syscall.ENOENT && err1.Err != syscall.ECONNREFUSED {
glog.Warningln("paxos Dial() failed: %v\n", err1)
}
return false
}
defer c.Close()
err = c.Call(name, args, reply)
if err == nil {
return true
}
glog.Infoln(err)
return false
}
