Push in read-only status

Similar to DNS autoclustering, the Store doesn't know its intended
read-only state.

cmd/rqlited/main.go

@@ -322,7 +322,7 @@ func createDiscoService(cfg *Config, str *store.Store) (*disco.Service, error) {
 		return nil, fmt.Errorf("invalid disco service: %s", cfg.DiscoMode)
 	}
 
-	return disco.NewService(c, str), nil
+	return disco.NewService(c, str, disco.VoterSuffrage(!cfg.RaftNonVoter)), nil
 }
 
 func startHTTPService(cfg *Config, str *store.Store, cltr *cluster.Client, credStr *auth.CredentialsStore) (*httpd.Service, error) {

disco/service.go

@@ -37,14 +37,33 @@ type Store interface {
 	// IsLeader returns whether this node is the Leader.
 	IsLeader() bool
 
-	// IsVoter returns whether this node is a voter. Only Voters can be Leaders.
-	IsVoter() (bool, error)
-
 	// RegisterLeaderChange registers a channel that will be notified when
 	// a leadership change occurs.
 	RegisterLeaderChange(c chan<- struct{})
 }
 
+// Suffrage is the type of suffrage -- voting or non-voting -- a node has.
+type Suffrage int
+
+const (
+	SuffrageUnknown Suffrage = iota
+	Voter
+	NonVoter
+)
+
+// VoterSuffrage returns a Suffrage based on the given boolean.
+func VoterSuffrage(b bool) Suffrage {
+	if b {
+		return Voter
+	}
+	return NonVoter
+}
+
+// IsVoter returns whether the Suffrage indicates a Voter.
+func (s Suffrage) IsVoter() bool {
+	return s == Voter
+}
+
 // Service represents a Discovery Service instance.
 type Service struct {
 	RegisterInterval time.Duration
@@ -52,6 +71,7 @@ type Service struct {
 
 	c   Client
 	s   Store
+	suf Suffrage
 
 	logger *log.Logger
 
@@ -60,11 +80,11 @@ type Service struct {
 }
 
 // NewService returns an instantiated Discovery Service.
-func NewService(c Client, s Store) *Service {
+func NewService(c Client, s Store, suf Suffrage) *Service {
 	return &Service{
 		c:                c,
 		s:                s,
-
+		suf:              suf,
 		RegisterInterval: 3 * time.Second,
 		ReportInterval:   10 * time.Second,
 		logger:           log.New(os.Stderr, "[disco] ", log.LstdFlags),
@@ -84,7 +104,7 @@ func (s *Service) Register(id, apiAddr, addr string) (bool, string, error) {
 			return false, cRaftAddr, nil
 		}
 
-		if s.isVoter() {
+		if s.suf.IsVoter() {
 			ok, err = s.c.InitializeLeader(id, apiAddr, addr)
 			if err != nil {
 				s.logger.Printf("failed to initialize as Leader: %s", err.Error())
@@ -157,8 +177,3 @@ func (s *Service) updateContact(t time.Time) {
 	defer s.mu.Unlock()
 	s.lastContact = t
 }
-
-func (s *Service) isVoter() bool {
-	v, _ := s.s.IsVoter()
-	return v
-}

disco/service_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 func Test_NewServce(t *testing.T) {
-	s := NewService(&mockClient{}, &mockStore{})
+	s := NewService(&mockClient{}, &mockStore{}, Voter)
 	if s == nil {
 		t.Fatalf("service is nil")
 	}
@@ -24,7 +24,7 @@ func Test_RegisterGetLeaderOK(t *testing.T) {
 	}
 	c := &mockStore{}
 
-	s := NewService(m, c)
+	s := NewService(m, c, Voter)
 	s.RegisterInterval = 10 * time.Millisecond
 
 	ok, addr, err := s.Register("1", "localhost:4001", "localhost:4002")
@@ -52,7 +52,7 @@ func Test_RegisterInitializeLeader(t *testing.T) {
 	}
 	c := &mockStore{}
 
-	s := NewService(m, c)
+	s := NewService(m, c, Voter)
 	s.RegisterInterval = 10 * time.Millisecond
 
 	ok, addr, err := s.Register("1", "localhost:4001", "localhost:4002")
@@ -82,12 +82,8 @@ func Test_RegisterNonVoter(t *testing.T) {
 		return false, nil
 	}
 
-	c := &mockStore{
-		isVoterFn: func() (bool, error) {
-			return false, nil
-		},
-	}
-	s := NewService(m, c)
+	c := &mockStore{}
+	s := NewService(m, c, NonVoter)
 	s.RegisterInterval = 10 * time.Millisecond
 
 	ok, addr, err := s.Register("1", "localhost:4001", "localhost:4002")
@@ -120,7 +116,7 @@ func Test_StartReportingTimer(t *testing.T) {
 		return true
 	}
 
-	s := NewService(m, c)
+	s := NewService(m, c, Voter)
 	s.ReportInterval = 10 * time.Millisecond
 
 	go s.StartReporting("1", "localhost:4001", "localhost:4002")
@@ -147,7 +143,7 @@ func Test_StartReportingChange(t *testing.T) {
 	}
 
 	wg.Add(1)
-	s := NewService(m, c)
+	s := NewService(m, c, Voter)
 	s.ReportInterval = 10 * time.Minute // Nothing will happen due to timer.
 	done := s.StartReporting("1", "localhost:4001", "localhost:4002")
 
@@ -190,7 +186,6 @@ func (m *mockClient) String() string {
 
 type mockStore struct {
 	isLeaderFn             func() bool
-	isVoterFn              func() (bool, error)
 	registerLeaderChangeFn func(c chan<- struct{})
 }
 
@@ -201,13 +196,6 @@ func (m *mockStore) IsLeader() bool {
 	return false
 }
 
-func (m *mockStore) IsVoter() (bool, error) {
-	if m.isVoterFn != nil {
-		return m.isVoterFn()
-	}
-	return true, nil
-}
-
 func (m *mockStore) RegisterLeaderChange(c chan<- struct{}) {
 	if m.registerLeaderChangeFn != nil {
 		m.registerLeaderChangeFn(c)