Added timeout functionality to Servers (#3192)

* Added timeout functionality to servers

currently only possible on the pairnig serve

* Removed logging (like a mad man)

* handling linter erroring

server/pairing/payload_manager.go

@@ -61,6 +61,9 @@ type PayloadSourceConfig struct {
 	// they are required in other cases
 	KeyUID   string `json:"keyUID"`
 	Password string `json:"password"`
+
+	// Timeout the number of milliseconds after which the pairing server will automatically terminate
+	Timeout uint `json:"timeout"`
 }
 
 // AccountPayloadManagerConfig represents the initialisation parameters required for a AccountPayloadManager

server/pairing/server.go

@@ -76,7 +76,7 @@ func NewPairingServer(backend *api.GethStatusBackend, config *Config) (*Server,
 		return nil, err
 	}
 
-	return &Server{Server: server.NewServer(
+	s := &Server{Server: server.NewServer(
 		config.Cert,
 		config.Hostname,
 		nil,
@@ -88,7 +88,10 @@ func NewPairingServer(backend *api.GethStatusBackend, config *Config) (*Server,
 		PayloadManager:           pm,
 		cookieStore:              cs,
 		rawMessagePayloadManager: rmpm,
-	}, nil
+	}
+	s.SetTimeout(config.Timeout)
+
+	return s, nil
 }
 
 // MakeConnectionParams generates a *ConnectionParams based on the Server's current state

server/pairing/server_pairing_test.go

@@ -41,6 +41,39 @@ func (s *PairingServerSuite) TestMultiBackgroundForeground() {
 	s.Require().Regexp(regexp.MustCompile("(https://\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}:\\d{1,5})"), s.PS.MakeBaseURL().String()) // nolint: gosimple
 }
 
+func (s *PairingServerSuite) TestMultiTimeout() {
+	s.PS.SetTimeout(20)
+
+	err := s.PS.Start()
+	s.Require().NoError(err)
+
+	s.PS.ToBackground()
+	s.PS.ToForeground()
+	s.PS.ToBackground()
+	s.PS.ToBackground()
+	s.PS.ToForeground()
+	s.PS.ToForeground()
+
+	s.Require().Regexp(regexp.MustCompile("(https://\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}:\\d{1,5})"), s.PS.MakeBaseURL().String()) // nolint: gosimple
+
+	time.Sleep(7 * time.Millisecond)
+	s.PS.ToBackground()
+	time.Sleep(7 * time.Millisecond)
+	s.PS.ToForeground()
+	time.Sleep(7 * time.Millisecond)
+	s.PS.ToBackground()
+	time.Sleep(7 * time.Millisecond)
+	s.PS.ToBackground()
+	time.Sleep(7 * time.Millisecond)
+	s.PS.ToForeground()
+	time.Sleep(7 * time.Millisecond)
+	s.PS.ToForeground()
+
+	// Wait for timeout to expire
+	time.Sleep(40 * time.Millisecond)
+	s.Require().False(s.PS.IsRunning())
+}
+
 func (s *PairingServerSuite) TestPairingServer_StartPairing() {
 	// Replace PairingServer.PayloadManager with a MockEncryptOnlyPayloadManager
 	pm, err := NewMockEncryptOnlyPayloadManager(s.EphemeralAES)

server/server.go

@@ -18,15 +18,18 @@ type Server struct {
 	cert      *tls.Certificate
 	hostname  string
 	handlers  HandlerPatternMap
+
 	portManger
+	*timeoutManager
 }
 
 func NewServer(cert *tls.Certificate, hostname string, afterPortChanged func(int), logger *zap.Logger) Server {
 	return Server{
-		logger:     logger,
-		cert:       cert,
-		hostname:   hostname,
-		portManger: newPortManager(logger.Named("Server"), afterPortChanged),
+		logger:         logger,
+		cert:           cert,
+		hostname:       hostname,
+		portManger:     newPortManager(logger.Named("Server"), afterPortChanged),
+		timeoutManager: newTimeoutManager(),
 	}
 }
 
@@ -73,6 +76,13 @@ func (s *Server) listenAndServe() {
 
 	s.isRunning = true
 
+	s.StartTimeout(func() {
+		err := s.Stop()
+		if err != nil {
+			s.logger.Error("PairingServer termination fail", zap.Error(err))
+		}
+	})
+
 	err = s.server.Serve(listener)
 	if err != http.ErrServerClosed {
 		s.logger.Error("server failed unexpectedly, restarting", zap.Error(err))
@@ -82,11 +92,11 @@ func (s *Server) listenAndServe() {
 		}
 		return
 	}
-
 	s.isRunning = false
 }
 
 func (s *Server) resetServer() {
+	s.StopTimeout()
 	s.server = new(http.Server)
 	s.ResetPort()
 }
@@ -112,6 +122,7 @@ func (s *Server) Start() error {
 }
 
 func (s *Server) Stop() error {
+	s.StopTimeout()
 	if s.server != nil {
 		return s.server.Shutdown(context.Background())
 	}
@@ -119,6 +130,10 @@ func (s *Server) Stop() error {
 	return nil
 }
 
+func (s *Server) IsRunning() bool {
+	return s.isRunning
+}
+
 func (s *Server) ToForeground() {
 	if !s.isRunning && (s.server != nil) {
 		err := s.Start()

server/timeout.go

@@ -0,0 +1,92 @@
+package server
+
+import (
+	"sync"
+	"time"
+)
+
+// timeoutManager represents a discrete encapsulation of timeout functionality.
+// this struct expose 3 functions:
+//  - SetTimeout
+//  - StartTimeout
+//  - StopTimeout
+type timeoutManager struct {
+	// timeout number of milliseconds the timeout operation will run before executing the `terminate` func()
+	// 0 represents an inactive timeout
+	timeout uint
+
+	// exitQueue handles the cancel signal channels that circumvent timeout operations and prevent the
+	// execution of any `terminate` func()
+	exitQueue *exitQueueManager
+}
+
+// newTimeoutManager returns a fully qualified and initialised timeoutManager
+func newTimeoutManager() *timeoutManager {
+	return &timeoutManager{
+		exitQueue: &exitQueueManager{queue: []chan struct{}{}},
+	}
+}
+
+// SetTimeout sets the value of the timeoutManager.timeout
+func (t *timeoutManager) SetTimeout(milliseconds uint) {
+	t.timeout = milliseconds
+}
+
+// StartTimeout starts a timeout operation based on the set timeoutManager.timeout value
+// the given terminate func() will be executed once the timeout duration has passed
+func (t *timeoutManager) StartTimeout(terminate func()) {
+	if t.timeout == 0 {
+		return
+	}
+	t.StopTimeout()
+
+	exit := make(chan struct{}, 1)
+	t.exitQueue.add(exit)
+	go t.run(terminate, exit)
+}
+
+// StopTimeout terminates a timeout operation and exits gracefully
+func (t *timeoutManager) StopTimeout() {
+	if t.timeout == 0 {
+		return
+	}
+	t.exitQueue.empty()
+}
+
+// run inits the main timeout run function that awaits for the exit command to be triggered or for the
+// timeout duration to elapse and trigger the parameter terminate function.
+func (t *timeoutManager) run(terminate func(), exit chan struct{}) {
+	select {
+	case <-exit:
+		return
+	case <-time.After(time.Duration(t.timeout) * time.Millisecond):
+		terminate()
+		return
+	}
+}
+
+// exitQueueManager
+type exitQueueManager struct {
+	queue     []chan struct{}
+	queueLock sync.Mutex
+}
+
+// add handles new exit channels adding them to the exit queue
+func (e *exitQueueManager) add(exit chan struct{}) {
+	e.queueLock.Lock()
+	defer e.queueLock.Unlock()
+
+	e.queue = append(e.queue, exit)
+}
+
+// empty sends a signal to every exit channel in the queue and then resets the queue
+func (e *exitQueueManager) empty() {
+	e.queueLock.Lock()
+	defer e.queueLock.Unlock()
+
+	for i := range e.queue {
+		e.queue[i] <- struct{}{}
+	}
+
+	e.queue = []chan struct{}{}
+}

server/timeout_test.go

@@ -0,0 +1,68 @@
+package server
+
+import (
+	"crypto/rand"
+	"math/big"
+	"testing"
+	"time"
+)
+
+func TestTimeoutManager(t *testing.T) {
+	tm := newTimeoutManager()
+
+	// test 0 timeout means timeout does not occur
+	tm.SetTimeout(0)
+
+	// test fuzzing - 0 timeout - multiple sequential calls to random init and stop funcs
+	for i := 0; i < 30; i++ {
+		b, err := rand.Int(rand.Reader, big.NewInt(2))
+		if err != nil {
+			t.Error(err)
+		}
+
+		if b.Int64() == 1 {
+			tm.StartTimeout(t.FailNow)
+		} else {
+			tm.StopTimeout()
+		}
+	}
+
+	// test fuzzing - random timeout - multiple sequential calls to random init and stop funcs
+	for i := 0; i < 30; i++ {
+		b, err := rand.Int(rand.Reader, big.NewInt(2))
+		if err != nil {
+			t.Error(err)
+		}
+		to, err := rand.Int(rand.Reader, big.NewInt(11))
+		if err != nil {
+			t.Error(err)
+		}
+
+		tm.SetTimeout(uint(to.Int64() * 20))
+
+		if b.Int64() == 1 {
+			tm.StartTimeout(t.FailNow)
+		} else {
+			tm.StopTimeout()
+		}
+		tm.StopTimeout()
+	}
+
+	// test StopTimeout() prevents termination func
+	tm.SetTimeout(20)
+	tm.StartTimeout(t.FailNow)
+	time.Sleep(10 * time.Millisecond)
+	tm.StopTimeout()
+
+	// test StartTimeout() executes termination func on timeout
+	ok := false
+	tm.SetTimeout(10)
+	tm.StartTimeout(func() {
+		ok = true
+	})
+	time.Sleep(20 * time.Millisecond)
+	if !ok {
+		t.FailNow()
+	}
+
+}