simulation: Fix k8s simulation issues. (#36)

* Refine peer server

* k8s ignore

* Keep peer server alive on k8s

* Stop validators from accepting new blocks after peer server has shut down.

* Add comment

3 files changed, 41 insertions, 9 deletions

diff --git a/.gitignore b/.gitignore
index ef110dd..f8cb90c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,5 +20,8 @@
 vendor
 build
 simulation/kubernetes/build
+simulation/kubernetes/*.log
+simulation/kubernetes/config.toml
+simulation/kubernetes/validator.yaml
 .dep
 
diff --git a/simulation/peer-server.go b/simulation/peer-server.go
index bae323e..43a1c2b 100644
--- a/simulation/peer-server.go
+++ b/simulation/peer-server.go
@@ -49,6 +49,15 @@ func NewPeerServer() *PeerServer {
 	}
 }
 
+// isValidator checks if vID is in p.peers. If peer server restarts but
+// validators are not, it will cause panic if validators send message.
+func (p *PeerServer) isValidator(vID types.ValidatorID) bool {
+	p.peersMu.Lock()
+	defer p.peersMu.Unlock()
+	_, exist := p.peers[vID]
+	return exist
+}
+
 // Run starts the peer server.
 func (p *PeerServer) Run(configPath string) {
 	cfg, err := config.Read(configPath)
@@ -84,6 +93,7 @@ func (p *PeerServer) Run(configPath string) {
 		if len(p.peers) == cfg.Validator.Num {
 			log.Println("All peers connected.")
 		}
+		w.WriteHeader(http.StatusOK)
 	}
 
 	peersHandler := func(w http.ResponseWriter, r *http.Request) {
@@ -102,6 +112,7 @@ func (p *PeerServer) Run(configPath string) {
 			return
 		}
 
+		w.WriteHeader(http.StatusOK)
 		w.Header().Set("Content-Type", "application/json")
 		w.Write(jsonText)
 	}
@@ -131,6 +142,7 @@ func (p *PeerServer) Run(configPath string) {
 			return
 		}
 
+		w.WriteHeader(http.StatusOK)
 		w.Header().Set("Content-Type", "application/json")
 		w.Write(jsonText)
 	}
@@ -139,8 +151,6 @@ func (p *PeerServer) Run(configPath string) {
 		defer r.Body.Close()
 
 		idString := r.Header.Get("ID")
-
-		defer r.Body.Close()
 		body, err := ioutil.ReadAll(r.Body)
 		if err != nil {
 			w.WriteHeader(http.StatusBadRequest)
@@ -159,6 +169,11 @@ func (p *PeerServer) Run(configPath string) {
 			return
 		}
 
+		if !p.isValidator(id) {
+			w.WriteHeader(http.StatusForbidden)
+			return
+		}
+
 		w.WriteHeader(http.StatusOK)
 
 		p.peerTotalOrderMu.Lock()
@@ -187,15 +202,17 @@ func (p *PeerServer) Run(configPath string) {
 	stopServer := make(chan struct{})
 
 	messageHandler := func(w http.ResponseWriter, r *http.Request) {
-		p.peersMu.Lock()
-		defer p.peersMu.Unlock()
 		defer r.Body.Close()
 
 		idString := r.Header.Get("ID")
 		id := types.ValidatorID{}
 		id.UnmarshalText([]byte(idString))
 
-		defer r.Body.Close()
+		if !p.isValidator(id) {
+			w.WriteHeader(http.StatusForbidden)
+			return
+		}
+
 		body, err := ioutil.ReadAll(r.Body)
 		if err != nil {
 			w.WriteHeader(http.StatusBadRequest)
@@ -264,4 +281,10 @@ func (p *PeerServer) Run(configPath string) {
 	if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
 		log.Fatalf("Error starting server %v\n", err)
 	}
+
+	// Do not exit when we are in TCP node, since k8s will restart the pod and
+	// cause confusions.
+	if cfg.Networking.Type == config.NetworkTypeTCP {
+		select {}
+	}
 }
diff --git a/simulation/validator.go b/simulation/validator.go
index 69ee317..a30420e 100644
--- a/simulation/validator.go
+++ b/simulation/validator.go
@@ -78,11 +78,11 @@ func (v *Validator) GetID() types.ValidatorID {
 func (v *Validator) Run() {
 	v.msgChannel = v.network.Join(v)
 
-	isStopped := make(chan struct{})
+	isStopped := make(chan struct{}, 2)
 	isShutdown := make(chan struct{})
 
 	v.BroadcastGenesisBlock()
-	go v.MsgServer()
+	go v.MsgServer(isStopped)
 	go v.CheckServerInfo(isShutdown)
 	go v.BlockProposer(isStopped, isShutdown)
 
@@ -116,10 +116,15 @@ func (v *Validator) CheckServerInfo(isShutdown chan struct{}) {
 }
 
 // MsgServer listen to the network channel for message and handle it.
-func (v *Validator) MsgServer() {
+func (v *Validator) MsgServer(isStopped chan struct{}) {
 	var pendingBlocks []*types.Block
 	for {
-		msg := <-v.msgChannel
+		var msg interface{}
+		select {
+		case msg = <-v.msgChannel:
+		case <-isStopped:
+			return
+		}
 
 		switch val := msg.(type) {
 		case *types.Block:
@@ -200,6 +205,7 @@ ProposingBlockLoop:
 		select {
 		case <-isShutdown:
 			isStopped <- struct{}{}
+			isStopped <- struct{}{}
 			break ProposingBlockLoop
 		default:
 			break