Add server certificate manager

This certificate manager will request a leaf certificate for server
agents and then keep them up to date.

agent/agent.go

@@ -37,6 +37,7 @@ import (
 	"github.com/hashicorp/consul/agent/checks"
 	"github.com/hashicorp/consul/agent/config"
 	"github.com/hashicorp/consul/agent/consul"
+	"github.com/hashicorp/consul/agent/consul/servercert"
 	"github.com/hashicorp/consul/agent/dns"
 	external "github.com/hashicorp/consul/agent/grpc-external"
 	"github.com/hashicorp/consul/agent/local"
@@ -353,6 +354,9 @@ type Agent struct {
 	// based on the current consul configuration.
 	tlsConfigurator *tlsutil.Configurator
 
+	// certManager manages the lifecycle of the internally-managed server certificate.
+	certManager *servercert.CertManager
+
 	// httpConnLimiter is used to limit connections to the HTTP server by client
 	// IP.
 	httpConnLimiter connlimit.Limiter
@@ -583,6 +587,24 @@ func (a *Agent) Start(ctx context.Context) error {
 			return fmt.Errorf("Failed to start Consul server: %v", err)
 		}
 		a.delegate = server
+
+		if a.config.PeeringEnabled && a.config.ConnectEnabled {
+			d := servercert.Deps{
+				Logger: a.logger.Named("server.cert-manager"),
+				Config: servercert.Config{
+					Datacenter:  a.config.Datacenter,
+					ACLsEnabled: a.config.ACLsEnabled,
+				},
+				Cache:           a.cache,
+				GetStore:        func() servercert.Store { return server.FSM().State() },
+				TLSConfigurator: a.tlsConfigurator,
+			}
+			a.certManager = servercert.NewCertManager(d)
+			if err := a.certManager.Start(&lib.StopChannelContext{StopCh: a.shutdownCh}); err != nil {
+				return fmt.Errorf("failed to start server cert manager: %w", err)
+			}
+		}
+
 	} else {
 		client, err := consul.NewClient(consulCfg, a.baseDeps.Deps)
 		if err != nil {

agent/agent_test.go

@@ -5984,6 +5984,71 @@ func TestAgent_startListeners(t *testing.T) {
 
 }
 
+func TestAgent_ServerCertificate(t *testing.T) {
+	if testing.Short() {
+		t.Skip("too slow for testing.Short")
+	}
+
+	const expectURI = "spiffe://11111111-2222-3333-4444-555555555555.consul/agent/server/dc/dc1"
+
+	// Leader should acquire a sever cert after bootstrapping.
+	a1 := NewTestAgent(t, `
+node_name = "a1"
+acl {
+	enabled = true
+	tokens {
+		initial_management = "root"
+		default = "root"
+	}
+}
+connect {
+	enabled = true
+}
+peering {
+	enabled = true
+}`)
+	defer a1.Shutdown()
+	testrpc.WaitForTestAgent(t, a1.RPC, "dc1")
+
+	retry.Run(t, func(r *retry.R) {
+		cert := a1.tlsConfigurator.AutoEncryptCert()
+		require.NotNil(r, cert)
+		require.Len(r, cert.URIs, 1)
+		require.Equal(r, expectURI, cert.URIs[0].String())
+	})
+
+	// Join a follower, and it should be able to acquire a server cert as well.
+	a2 := NewTestAgent(t, `
+node_name = "a2"
+bootstrap = false
+acl {
+	enabled = true
+	tokens {
+		initial_management = "root"
+		default = "root"
+	}
+}
+connect {
+	enabled = true
+}
+peering {
+	enabled = true
+}`)
+	defer a2.Shutdown()
+
+	_, err := a2.JoinLAN([]string{fmt.Sprintf("127.0.0.1:%d", a1.Config.SerfPortLAN)}, nil)
+	require.NoError(t, err)
+
+	testrpc.WaitForTestAgent(t, a2.RPC, "dc1")
+
+	retry.Run(t, func(r *retry.R) {
+		cert := a2.tlsConfigurator.AutoEncryptCert()
+		require.NotNil(r, cert)
+		require.Len(r, cert.URIs, 1)
+		require.Equal(r, expectURI, cert.URIs[0].String())
+	})
+}
+
 func getExpectedCaPoolByFile(t *testing.T) *x509.CertPool {
 	pool := x509.NewCertPool()
 	data, err := ioutil.ReadFile("../test/ca/root.cer")

agent/cache-types/connect_ca_leaf.go

@@ -690,17 +690,19 @@ func (c *ConnectCALeaf) generateNewLeaf(req *ConnectCALeafRequest,
 type ConnectCALeafRequest struct {
 	Token         string
 	Datacenter    string
-	Service        string              // Service name, not ID
-	Agent          string              // Agent name, not ID
-	Kind           structs.ServiceKind // only mesh-gateway for now
-	Server         bool
 	DNSSAN        []string
 	IPSAN         []net.IP
 	MinQueryIndex uint64
 	MaxQueryTime  time.Duration
+	acl.EnterpriseMeta
 	MustRevalidate bool
 
-	acl.EnterpriseMeta
+	// The following flags indicate the entity we are requesting a cert for.
+	// Only one of these must be specified.
+	Service string              // Given a Service name, not ID, the request is for a SpiffeIDService.
+	Agent   string              // Given an Agent name, not ID, the request is for a SpiffeIDAgent.
+	Kind    structs.ServiceKind // Given "mesh-gateway", the request is for a SpiffeIDMeshGateway. No other kinds supported.
+	Server  bool                // If true, the request is for a SpiffeIDServer.
 }
 
 func (r *ConnectCALeafRequest) Key() string {

agent/consul/acl_server.go

@@ -110,7 +110,7 @@ type serverACLResolverBackend struct {
 }
 
 func (s *serverACLResolverBackend) IsServerManagementToken(token string) bool {
-	mgmt, err := s.getSystemMetadata(structs.ServerManagementToken)
+	mgmt, err := s.getSystemMetadata(structs.ServerManagementTokenAccessorID)
 	if err != nil {
 		s.logger.Debug("failed to fetch server management token: %w", err)
 		return false

agent/consul/acl_test.go

@@ -2209,7 +2209,7 @@ func TestACLResolver_ServerManagementToken(t *testing.T) {
 	authz, err := r.ResolveToken(testToken)
 	require.NoError(t, err)
 	require.NotNil(t, authz.ACLIdentity)
-	require.Equal(t, structs.ServerManagementToken, authz.ACLIdentity.ID())
+	require.Equal(t, structs.ServerManagementTokenAccessorID, authz.ACLIdentity.ID())
 	require.NotNil(t, authz.Authorizer)
 	require.Equal(t, acl.ManageAll(), authz.Authorizer)
 }

agent/consul/leader.go

@@ -538,7 +538,7 @@ func (s *Server) initializeACLs(ctx context.Context) error {
 		if err != nil {
 			return fmt.Errorf("failed to generate the secret ID for the server management token: %w", err)
 		}
-		if err := s.setSystemMetadataKey(structs.ServerManagementToken, secretID); err != nil {
+		if err := s.setSystemMetadataKey(structs.ServerManagementTokenAccessorID, secretID); err != nil {
 			return fmt.Errorf("failed to persist server management token: %w", err)
 		}
 

agent/consul/leader_test.go

@@ -1297,7 +1297,7 @@ func TestLeader_ACL_Initialization(t *testing.T) {
 			require.NoError(t, err)
 			require.NotNil(t, policy)
 
-			serverToken, err := s1.getSystemMetadata(structs.ServerManagementToken)
+			serverToken, err := s1.getSystemMetadata(structs.ServerManagementTokenAccessorID)
 			require.NoError(t, err)
 			require.NotEmpty(t, serverToken)
 

agent/consul/servercert/manager.go

@@ -0,0 +1,267 @@
+package servercert
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/hashicorp/consul/agent/cache"
+	cachetype "github.com/hashicorp/consul/agent/cache-types"
+	"github.com/hashicorp/consul/agent/connect"
+	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/consul/lib/retry"
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/go-memdb"
+)
+
+// Correlation ID for leaf cert watches.
+const leafWatchID = "leaf"
+
+// Cache is an interface to represent the necessary methods of the agent/cache.Cache.
+// It is used to request and renew the server leaf certificate.
+type Cache interface {
+	Notify(ctx context.Context, t string, r cache.Request, correlationID string, ch chan<- cache.UpdateEvent) error
+}
+
+// TLSConfigurator is an interface to represent the necessary methods of the tlsutil.Configurator.
+// It is used to apply the server leaf certificate and server name.
+type TLSConfigurator interface {
+	UpdateAutoTLSCert(pub, priv string) error
+	UpdateAutoTLSPeeringServerName(name string)
+}
+
+// Store is an interface to represent the necessary methods of the state.Store.
+// It is used to fetch the CA Config to getStore the trust domain in the TLSConfigurator.
+type Store interface {
+	CAConfig(ws memdb.WatchSet) (uint64, *structs.CAConfiguration, error)
+	SystemMetadataGet(ws memdb.WatchSet, key string) (uint64, *structs.SystemMetadataEntry, error)
+	AbandonCh() <-chan struct{}
+}
+
+type Config struct {
+	// Datacenter is the datacenter name the server is configured with.
+	Datacenter string
+
+	// ACLsEnabled indicates whether the ACL system is enabled on this server.
+	ACLsEnabled bool
+}
+
+type Deps struct {
+	Config          Config
+	Logger          hclog.Logger
+	Cache           Cache
+	GetStore        func() Store
+	TLSConfigurator TLSConfigurator
+	waiter          retry.Waiter
+}
+
+// CertManager is responsible for requesting and renewing the leaf cert for server agents.
+// The server certificate is managed internally and used for peering control-plane traffic
+// to the TLS-enabled external gRPC port.
+type CertManager struct {
+	logger hclog.Logger
+
+	// config contains agent configuration necessary for the cert manager to operate.
+	config Config
+
+	// cache provides an API to issue internal RPC requests and receive notifications
+	// when there are changes.
+	cache Cache
+
+	// cacheUpdateCh receives notifications of cache update events for resources watched.
+	cacheUpdateCh chan cache.UpdateEvent
+
+	// getStore returns the server state getStore for read-only access.
+	getStore func() Store
+
+	// tlsConfigurator receives the leaf cert and peering server name updates from the cert manager.
+	tlsConfigurator TLSConfigurator
+
+	// waiter contains the waiter for exponential backoff between retries.
+	waiter retry.Waiter
+}
+
+func NewCertManager(deps Deps) *CertManager {
+	return &CertManager{
+		config:          deps.Config,
+		logger:          deps.Logger,
+		cache:           deps.Cache,
+		cacheUpdateCh:   make(chan cache.UpdateEvent, 1),
+		getStore:        deps.GetStore,
+		tlsConfigurator: deps.TLSConfigurator,
+		waiter: retry.Waiter{
+			MinFailures: 1,
+			MinWait:     1 * time.Second,
+			MaxWait:     5 * time.Minute,
+			Jitter:      retry.NewJitter(20),
+		},
+	}
+}
+
+func (m *CertManager) Start(ctx context.Context) error {
+	if err := m.initializeWatches(ctx); err != nil {
+		return fmt.Errorf("failed to set up certificate watches: %w", err)
+	}
+	go m.handleUpdates(ctx)
+
+	m.logger.Info("initialized server certificate management")
+	return nil
+}
+
+func (m *CertManager) initializeWatches(ctx context.Context) error {
+	if m.config.ACLsEnabled {
+		// If ACLs are enabled we need to watch for server token updates and set/reset
+		// leaf cert updates as token updates arrive.
+		go m.watchServerToken(ctx)
+	} else {
+		// If ACLs are disabled we set up a single cache notification for leaf certs.
+		if err := m.watchLeafCert(ctx); err != nil {
+			return fmt.Errorf("failed to watch leaf: %w", err)
+		}
+	}
+	go m.watchCAConfig(ctx)
+
+	return nil
+}
+
+func (m *CertManager) watchServerToken(ctx context.Context) {
+	// We keep the last iteration's cancel function to reset watches.
+	var (
+		notifyCtx context.Context
+		cancel    context.CancelFunc = func() {}
+	)
+	retryLoopBackoff(ctx, m.waiter, func() error {
+		ws := memdb.NewWatchSet()
+		ws.Add(m.getStore().AbandonCh())
+
+		_, token, err := m.getStore().SystemMetadataGet(ws, structs.ServerManagementTokenAccessorID)
+		if err != nil {
+			return err
+		}
+		if token == nil {
+			m.logger.Debug("ACLs have not finished initializing")
+			return nil
+		}
+		if token.Value == "" {
+			// This should never happen. If the leader stored a token with this key it will not be empty.
+			return fmt.Errorf("empty token")
+		}
+		m.logger.Debug("server management token watch fired - resetting leaf cert watch")
+
+		// Cancel existing the leaf cert watch and spin up new one any time the server token changes.
+		// The watch needs the current token as set by the leader since certificate signing requests go to the leader.
+		fmt.Println("canceling and resetting")
+		cancel()
+		notifyCtx, cancel = context.WithCancel(ctx)
+
+		req := cachetype.ConnectCALeafRequest{
+			Datacenter: m.config.Datacenter,
+			Token:      token.Value,
+			Server:     true,
+		}
+		if err := m.cache.Notify(notifyCtx, cachetype.ConnectCALeafName, &req, leafWatchID, m.cacheUpdateCh); err != nil {
+			return fmt.Errorf("failed to setup leaf cert notifications: %w", err)
+		}
+
+		ws.WatchCtx(ctx)
+		return nil
+
+	}, func(err error) {
+		m.logger.Error("failed to watch server management token", "error", err)
+	})
+}
+
+func (m *CertManager) watchLeafCert(ctx context.Context) error {
+	req := cachetype.ConnectCALeafRequest{
+		Datacenter: m.config.Datacenter,
+		Server:     true,
+	}
+	if err := m.cache.Notify(ctx, cachetype.ConnectCALeafName, &req, leafWatchID, m.cacheUpdateCh); err != nil {
+		return fmt.Errorf("failed to setup leaf cert notifications: %w", err)
+	}
+
+	return nil
+}
+
+func (m *CertManager) watchCAConfig(ctx context.Context) {
+	retryLoopBackoff(ctx, m.waiter, func() error {
+		ws := memdb.NewWatchSet()
+		ws.Add(m.getStore().AbandonCh())
+
+		_, conf, err := m.getStore().CAConfig(ws)
+		if err != nil {
+			return fmt.Errorf("failed to fetch CA configuration from the state getStore: %w", err)
+		}
+		if conf == nil || conf.ClusterID == "" {
+			m.logger.Debug("CA has not finished initializing")
+			return nil
+		}
+
+		id := connect.SpiffeIDSigningForCluster(conf.ClusterID)
+		name := connect.PeeringServerSAN(m.config.Datacenter, id.Host())
+
+		m.logger.Debug("CA config watch fired - updating auto TLS server name", "name", name)
+		m.tlsConfigurator.UpdateAutoTLSPeeringServerName(name)
+
+		ws.WatchCtx(ctx)
+		return nil
+
+	}, func(err error) {
+		m.logger.Error("failed to watch CA config", "error", err)
+	})
+}
+
+func retryLoopBackoff(ctx context.Context, waiter retry.Waiter, loopFn func() error, errorFn func(error)) {
+	for {
+		if err := waiter.Wait(ctx); err != nil {
+			// The error will only be non-nil if the context is canceled.
+			return
+		}
+
+		if err := loopFn(); err != nil {
+			errorFn(err)
+			continue
+		}
+
+		// Reset the failure count seen by the waiter if there was no error.
+		waiter.Reset()
+	}
+}
+
+func (m *CertManager) handleUpdates(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			m.logger.Debug("context canceled")
+			return
+
+		case event := <-m.cacheUpdateCh:
+			m.logger.Debug("got cache update event", "correlationID", event.CorrelationID, "error", event.Err)
+
+			if err := m.handleLeafUpdate(event); err != nil {
+				m.logger.Error("failed to handle cache update event", "error", err)
+			}
+		}
+	}
+}
+
+func (m *CertManager) handleLeafUpdate(event cache.UpdateEvent) error {
+	if event.Err != nil {
+		return fmt.Errorf("leaf cert watch returned an error: %w", event.Err)
+	}
+	if event.CorrelationID != leafWatchID {
+		return fmt.Errorf("got unexpected update correlation ID %q while expecting %q", event.CorrelationID, leafWatchID)
+	}
+
+	leaf, ok := event.Result.(*structs.IssuedCert)
+	if !ok {
+		return fmt.Errorf("got invalid type in leaf cert watch response: %T", event.Result)
+	}
+
+	m.logger.Debug("leaf certificate watch fired - updating auto TLS certificate", "uri", leaf.ServerURI)
+
+	if err := m.tlsConfigurator.UpdateAutoTLSCert(leaf.CertPEM, leaf.PrivateKeyPEM); err != nil {
+		return fmt.Errorf("failed to getStore the server leaf cert: %w", err)
+	}
+	return nil
+}

agent/consul/servercert/manager_test.go

@@ -0,0 +1,296 @@
+package servercert
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/hashicorp/consul/agent/cache"
+	"github.com/hashicorp/consul/agent/connect"
+	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/consul/lib/retry"
+	"github.com/hashicorp/consul/sdk/testutil"
+	"github.com/hashicorp/go-memdb"
+	"github.com/stretchr/testify/require"
+)
+
+type fakeStore struct {
+	// conf is the current CA configuration stored in the fakeStore.
+	conf chan *structs.CAConfiguration
+
+	// tokenEntry is the current server token entry stored in the fakeStore.
+	tokenEntry chan *structs.SystemMetadataEntry
+
+	// tokenCanceler will unblock the WatchSet for the token entry.
+	tokenCanceler <-chan struct{}
+}
+
+func (s *fakeStore) CAConfig(_ memdb.WatchSet) (uint64, *structs.CAConfiguration, error) {
+	select {
+	case conf := <-s.conf:
+		return 0, conf, nil
+	default:
+		return 0, nil, nil
+	}
+}
+
+func (s *fakeStore) setCAConfig() {
+	s.conf <- &structs.CAConfiguration{
+		ClusterID: connect.TestClusterID,
+	}
+}
+
+func (s *fakeStore) SystemMetadataGet(ws memdb.WatchSet, _ string) (uint64, *structs.SystemMetadataEntry, error) {
+	select {
+	case entry := <-s.tokenEntry:
+		ws.Add(s.tokenCanceler)
+		return 0, entry, nil
+	default:
+		return 0, nil, nil
+	}
+}
+
+func (s *fakeStore) setServerToken(token string, canceler <-chan struct{}) {
+	s.tokenCanceler = canceler
+	s.tokenEntry <- &structs.SystemMetadataEntry{
+		Key:   structs.ServerManagementTokenAccessorID,
+		Value: token,
+	}
+}
+
+func (s *fakeStore) AbandonCh() <-chan struct{} {
+	return make(<-chan struct{})
+}
+
+type testCert struct {
+	pub  string
+	priv string
+}
+
+type fakeTLSConfigurator struct {
+	cert              testCert
+	peeringServerName string
+
+	// syncCh is used to signal that an update was handled.
+	// It synchronizes readers and writers in different goroutines.
+	syncCh chan struct{}
+}
+
+func (u *fakeTLSConfigurator) UpdateAutoTLSCert(pub, priv string) error {
+	u.cert = testCert{
+		pub:  pub,
+		priv: priv,
+	}
+	u.syncCh <- struct{}{}
+	return nil
+}
+
+func (u *fakeTLSConfigurator) UpdateAutoTLSPeeringServerName(name string) {
+	u.peeringServerName = name
+	u.syncCh <- struct{}{}
+}
+
+func (u *fakeTLSConfigurator) timeoutIfNotUpdated(t *testing.T) error {
+	t.Helper()
+
+	select {
+	case <-u.syncCh:
+	case <-time.After(100 * time.Millisecond):
+		t.Fatalf("timed out")
+	}
+	return nil
+}
+
+type watchInfo struct {
+	ctx   context.Context
+	token string
+}
+
+type fakeCache struct {
+	updateCh chan<- cache.UpdateEvent
+
+	// watched is a map of watched correlation IDs to the ACL token of the request.
+	watched map[string]watchInfo
+
+	// syncCh is used to signal that Notify was called.
+	// It synchronizes readers and writers in different goroutines.
+	syncCh chan struct{}
+}
+
+func (c *fakeCache) triggerLeafUpdate() {
+	c.updateCh <- cache.UpdateEvent{
+		CorrelationID: leafWatchID,
+		Result: &structs.IssuedCert{
+			CertPEM:       "cert-pem",
+			PrivateKeyPEM: "key-pem",
+			ServerURI:     "test-uri",
+		},
+	}
+}
+
+func (c *fakeCache) Notify(ctx context.Context, t string, r cache.Request, correlationID string, ch chan<- cache.UpdateEvent) error {
+	c.watched[correlationID] = watchInfo{ctx: ctx, token: r.CacheInfo().Token}
+	c.updateCh = ch
+	c.syncCh <- struct{}{}
+	return nil
+}
+
+func (c *fakeCache) timeoutIfNotUpdated(t *testing.T) error {
+	t.Helper()
+
+	select {
+	case <-c.syncCh:
+	case <-time.After(100 * time.Millisecond):
+		t.Fatalf("timed out")
+	}
+	return nil
+}
+
+func testWaiter() retry.Waiter {
+	return retry.Waiter{
+		MinFailures: 1,
+		MinWait:     20 * time.Millisecond,
+		MaxWait:     20 * time.Millisecond,
+	}
+}
+
+func TestCertManager_ACLsDisabled(t *testing.T) {
+	tlsConfigurator := fakeTLSConfigurator{syncCh: make(chan struct{}, 1)}
+	cache := fakeCache{watched: make(map[string]watchInfo), syncCh: make(chan struct{}, 1)}
+	store := fakeStore{
+		conf:       make(chan *structs.CAConfiguration, 1),
+		tokenEntry: make(chan *structs.SystemMetadataEntry, 1),
+	}
+
+	mgr := NewCertManager(Deps{
+		Logger: testutil.Logger(t),
+		Config: Config{
+			Datacenter:  "my-dc",
+			ACLsEnabled: false,
+		},
+		TLSConfigurator: &tlsConfigurator,
+		Cache:           &cache,
+		GetStore:        func() Store { return &store },
+	})
+
+	// Override the default waiter to reduce time between retries.
+	mgr.waiter = testWaiter()
+
+	require.NoError(t, mgr.Start(context.Background()))
+
+	testutil.RunStep(t, "initial empty state", func(t *testing.T) {
+		require.Empty(t, tlsConfigurator.cert)
+		require.Empty(t, tlsConfigurator.peeringServerName)
+
+		require.Contains(t, cache.watched, leafWatchID)
+	})
+
+	testutil.RunStep(t, "leaf cert update", func(t *testing.T) {
+		cache.triggerLeafUpdate()
+
+		// Wait for the update to arrive.
+		require.NoError(t, tlsConfigurator.timeoutIfNotUpdated(t))
+
+		expect := testCert{
+			pub:  "cert-pem",
+			priv: "key-pem",
+		}
+		require.Equal(t, expect, tlsConfigurator.cert)
+	})
+
+	testutil.RunStep(t, "ca config update", func(t *testing.T) {
+		store.setCAConfig()
+
+		// Wait for the update to arrive.
+		require.NoError(t, tlsConfigurator.timeoutIfNotUpdated(t))
+
+		expect := connect.PeeringServerSAN(mgr.config.Datacenter, connect.TestTrustDomain)
+		require.Equal(t, expect, tlsConfigurator.peeringServerName)
+	})
+}
+
+func TestCertManager_ACLsEnabled(t *testing.T) {
+	tlsConfigurator := fakeTLSConfigurator{syncCh: make(chan struct{}, 1)}
+	cache := fakeCache{watched: make(map[string]watchInfo), syncCh: make(chan struct{}, 1)}
+	store := fakeStore{
+		conf:       make(chan *structs.CAConfiguration, 1),
+		tokenEntry: make(chan *structs.SystemMetadataEntry, 1),
+	}
+
+	mgr := NewCertManager(Deps{
+		Logger: testutil.Logger(t),
+		Config: Config{
+			Datacenter:  "my-dc",
+			ACLsEnabled: true,
+		},
+		TLSConfigurator: &tlsConfigurator,
+		Cache:           &cache,
+		GetStore:        func() Store { return &store },
+	})
+
+	// Override the default waiter to reduce time between retries.
+	mgr.waiter = testWaiter()
+
+	require.NoError(t, mgr.Start(context.Background()))
+
+	testutil.RunStep(t, "initial empty state", func(t *testing.T) {
+		require.Empty(t, tlsConfigurator.cert)
+		require.Empty(t, tlsConfigurator.peeringServerName)
+
+		require.Empty(t, cache.watched)
+	})
+
+	var leafCtx context.Context
+	tokenCanceler := make(chan struct{})
+
+	testutil.RunStep(t, "server token update", func(t *testing.T) {
+		store.setServerToken("first-secret", tokenCanceler)
+
+		require.NoError(t, cache.timeoutIfNotUpdated(t))
+
+		require.Contains(t, cache.watched, leafWatchID)
+		require.Equal(t, "first-secret", cache.watched[leafWatchID].token)
+
+		leafCtx = cache.watched[leafWatchID].ctx
+	})
+
+	testutil.RunStep(t, "leaf cert update", func(t *testing.T) {
+		cache.triggerLeafUpdate()
+
+		// Wait for the update to arrive.
+		require.NoError(t, tlsConfigurator.timeoutIfNotUpdated(t))
+
+		expect := testCert{
+			pub:  "cert-pem",
+			priv: "key-pem",
+		}
+		require.Equal(t, expect, tlsConfigurator.cert)
+	})
+
+	testutil.RunStep(t, "another server token update", func(t *testing.T) {
+		store.setServerToken("second-secret", nil)
+
+		// Fire the existing WatchSet to simulate a state store update.
+		tokenCanceler <- struct{}{}
+
+		// The leaf watch in the cache should have been reset.
+		require.NoError(t, cache.timeoutIfNotUpdated(t))
+
+		// The original leaf watch context should have been canceled.
+		require.Error(t, leafCtx.Err())
+
+		// A new leaf watch is expected with the new token.
+		require.Contains(t, cache.watched, leafWatchID)
+		require.Equal(t, "second-secret", cache.watched[leafWatchID].token)
+	})
+
+	testutil.RunStep(t, "ca config update", func(t *testing.T) {
+		store.setCAConfig()
+
+		// Wait for the update to arrive.
+		require.NoError(t, tlsConfigurator.timeoutIfNotUpdated(t))
+
+		expect := connect.PeeringServerSAN(mgr.config.Datacenter, connect.TestTrustDomain)
+		require.Equal(t, expect, tlsConfigurator.peeringServerName)
+	})
+}

agent/structs/acl.go

@@ -1840,7 +1840,7 @@ func (id *AgentRecoveryTokenIdentity) EnterpriseMetadata() *acl.EnterpriseMeta {
 	return nil
 }
 
-const ServerManagementToken = "server-management-token"
+const ServerManagementTokenAccessorID = "server-management-token"
 
 type ACLServerIdentity struct {
 	secretID string
@@ -1853,7 +1853,7 @@ func NewACLServerIdentity(secretID string) *ACLServerIdentity {
 }
 
 func (i *ACLServerIdentity) ID() string {
-	return ServerManagementToken
+	return ServerManagementTokenAccessorID
 }
 
 func (i *ACLServerIdentity) SecretToken() string {

lib/retry/retry.go

@@ -79,6 +79,7 @@ func (w *Waiter) delay() time.Duration {
 }
 
 // Reset the failure count to 0.
+// Reset must be called if the operation done after Wait did not fail.
 func (w *Waiter) Reset() {
 	w.failures = 0
 }
@@ -88,9 +89,13 @@ func (w *Waiter) Failures() int {
 	return int(w.failures)
 }
 
-// Wait increase the number of failures by one, and then blocks until the context
+// Wait increases the number of failures by one, and then blocks until the context
 // is cancelled, or until the wait time is reached.
+//
 // The wait time increases exponentially as the number of failures increases.
+// Every call to Wait increments the failures count, so Reset must be called
+// after Wait when there wasn't a failure.
+//
 // Wait will return ctx.Err() if the context is cancelled.
 func (w *Waiter) Wait(ctx context.Context) error {
 	w.failures++