[FIXED] Possible panic on startup when monitoring endpoint inspected

If some monitoring endpoints were inspected during the start process it could result in a panic due to a map read during a map set. Resolves #1235 Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
nats-io · Jan 30, 2022 · c6f1e64 · c6f1e64
1 parent a17a5b6
commit c6f1e64
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Showing 3 changed files with 86 additions and 12 deletions.
diff --git a/server/monitor.go b/server/monitor.go
@@ -172,21 +172,21 @@ func (s *StanServer) startMonitoring(nOpts *natsd.Options) error {
 func (s *StanServer) HandleRootz(w http.ResponseWriter, r *http.Request) {
 	fmt.Fprintf(w, `<html lang="en">
    <head>
-    <link rel="shortcut icon" href="http://nats.io/img/favicon.ico">
+    <link rel="shortcut icon" href="https://nats.io/img/favicon.ico">
     <style type="text/css">
       body { font-family: "Century Gothic", CenturyGothic, AppleGothic, sans-serif; font-size: 22; }
       a { margin-left: 32px; }
     </style>
   </head>
   <body>
-    <img src="http://nats.io/img/logo.png" alt="NATS Streaming">
+    <img src="https://nats.io/img/logo.png" alt="NATS Streaming">
     <br/>
 	<a href=.%s>server</a><br/>
 	<a href=.%s>store</a><br/>
 	<a href=.%s>clients</a><br/>
 	<a href=.%s>channels</a><br/>
     <br/>
-    <a href=http://nats.io/documentation/server/gnatsd-monitoring/>help</a>
+    <a href=https://docs.nats.io/legacy/stan/intro/monitoring/>help</a>
   </body>
 </html>`, ServerPath, StorePath, ClientsPath, ChannelsPath)
 }
@@ -198,15 +198,6 @@ func (s *StanServer) HandleServerz(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, fmt.Sprintf("Error getting information about channels state: %v", err), http.StatusInternalServerError)
 		return
 	}
-	var role string
-	var nodeID string
-	s.mu.RLock()
-	state := s.state
-	if s.raft != nil {
-		role = s.raft.State().String()
-		nodeID = s.info.NodeID
-	}
-	s.mu.RUnlock()
 
 	numSubs := s.numSubs()
 	now := time.Now()
@@ -227,6 +218,15 @@ func (s *StanServer) HandleServerz(w http.ResponseWriter, r *http.Request) {
 		maxFDs = int(limits.OpenFiles)
 	}
 
+	var role string
+	var nodeID string
+
+	s.mu.RLock()
+	state := s.state
+	if s.raft != nil {
+		role = s.raft.State().String()
+		nodeID = s.info.NodeID
+	}
 	serverz := &Serverz{
 		ClusterID:     s.info.ClusterID,
 		ServerID:      s.serverID,
@@ -250,6 +250,7 @@ func (s *StanServer) HandleServerz(w http.ResponseWriter, r *http.Request) {
 		OpenFDs:       fds,
 		MaxFDs:        maxFDs,
 	}
+	s.mu.RUnlock()
 	s.sendResponse(w, r, serverz)
 }
 
@@ -293,6 +294,7 @@ func (s *StanServer) HandleStorez(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, fmt.Sprintf("Error getting information about channels state: %v", err), http.StatusInternalServerError)
 		return
 	}
+	s.mu.RLock()
 	storez := &Storez{
 		ClusterID:  s.info.ClusterID,
 		ServerID:   s.serverID,
@@ -302,6 +304,7 @@ func (s *StanServer) HandleStorez(w http.ResponseWriter, r *http.Request) {
 		TotalMsgs:  count,
 		TotalBytes: bytes,
 	}
+	s.mu.RUnlock()
 	s.sendResponse(w, r, storez)
 }
 
@@ -353,6 +356,7 @@ func (s *StanServer) HandleClientsz(w http.ResponseWriter, r *http.Request) {
 			}
 		}
 		carr = carr[0:carrSize]
+		s.mu.RLock()
 		clientsz := &Clientsz{
 			ClusterID: s.info.ClusterID,
 			ServerID:  s.serverID,
@@ -363,6 +367,7 @@ func (s *StanServer) HandleClientsz(w http.ResponseWriter, r *http.Request) {
 			Count:     len(carr),
 			Clients:   carr,
 		}
+		s.mu.RUnlock()
 		s.sendResponse(w, r, clientsz)
 	}
 }
@@ -499,6 +504,7 @@ func (s *StanServer) HandleChannelsz(w http.ResponseWriter, r *http.Request) {
 		channels := s.channels.getAll()
 		totalChannels := len(channels)
 		minoff, maxoff := getMinMaxOffset(offset, limit, totalChannels)
+		s.mu.RLock()
 		channelsz := &Channelsz{
 			ClusterID: s.info.ClusterID,
 			ServerID:  s.serverID,
@@ -507,6 +513,7 @@ func (s *StanServer) HandleChannelsz(w http.ResponseWriter, r *http.Request) {
 			Limit:     limit,
 			Total:     totalChannels,
 		}
+		s.mu.RUnlock()
 		if subsOption == 1 {
 			carr := make([]*Channelz, 0, totalChannels)
 			for cn := range channels {

diff --git a/server/monitor_test.go b/server/monitor_test.go
@@ -24,6 +24,7 @@ import (
 	"reflect"
 	"runtime"
 	"strings"
+	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -1448,3 +1449,67 @@ func TestMonitorInOutMsgs(t *testing.T) {
 		t.Fatalf("Expected 15 outbound messages, got %v - %v", sz.InMsgs, sz.InBytes)
 	}
 }
+
+func TestMonitorNoPanicOnServerRestart(t *testing.T) {
+	resetPreviousHTTPConnections()
+	cleanupDatastore(t)
+	defer cleanupDatastore(t)
+	opts := getTestDefaultOptsForPersistentStore()
+
+	ns := natsdTest.RunDefaultServer()
+	defer ns.Shutdown()
+
+	opts.NATSServerURL = "nats://127.0.0.1:4222"
+	s := runMonitorServer(t, opts)
+	defer s.Shutdown()
+
+	sc := NewDefaultConnection(t)
+	defer sc.Close()
+
+	for i := 0; i < 100; i++ {
+		if _, err := sc.Subscribe(fmt.Sprintf("foo.%d", i+1),
+			func(_ *stan.Msg) {}, stan.DurableName("dur")); err != nil {
+			t.Fatalf("Error on subscribe: %v", err)
+		}
+	}
+
+	endpoints := []string{
+		"channelsz?subs=1",
+		"serverz",
+		"storez",
+		"clientsz",
+		"isFTActive",
+	}
+	for _, e := range endpoints {
+		s.Shutdown()
+
+		wg := sync.WaitGroup{}
+		wg.Add(1)
+		done := make(chan struct{})
+		go func() {
+			defer wg.Done()
+			url := fmt.Sprintf("http://%s:%d/streaming/", monitorHost, monitorPort)
+			for {
+				resp, err := http.DefaultClient.Get(url + e)
+				if err != nil {
+					continue
+				}
+				ioutil.ReadAll(resp.Body)
+				resp.Body.Close()
+				select {
+				case <-done:
+					return
+				default:
+				}
+			}
+		}()
+
+		s = runMonitorServer(t, opts)
+		defer s.Shutdown()
+
+		time.Sleep(100 * time.Millisecond)
+		close(done)
+		wg.Wait()
+	}
+	sc.Close()
+}
diff --git a/server/server.go b/server/server.go
@@ -2525,7 +2525,9 @@ func (s *StanServer) processRecoveredChannels(channels map[string]*stores.Recove
 	allSubs := make([]*subState, 0, 16)
 
 	for channelName, recoveredChannel := range channels {
+		s.channels.Lock()
 		channel, err := s.channels.create(s, channelName, recoveredChannel.Channel)
+		s.channels.Unlock()
 		if err != nil {
 			return nil, err
 		}