Make /api/debug/health return error when no backends are available

pkg/balance/router/router.go

@@ -29,6 +29,7 @@ type Router interface {
 	ConnEventReceiver
 
 	GetBackendSelector() BackendSelector
+	HealthyBackendCount() int
 	RefreshBackend()
 	RedirectConnections() error
 	ConnCount() int

pkg/balance/router/router_score.go

@@ -75,6 +75,22 @@ func (router *ScoreBasedRouter) GetBackendSelector() BackendSelector {
 	}
 }
 
+func (router *ScoreBasedRouter) HealthyBackendCount() int {
+	router.Lock()
+	defer router.Unlock()
+	if router.observeError != nil {
+		return 0
+	}
+
+	count := 0
+	for _, backend := range router.backends {
+		if backend.Healthy() {
+			count++
+		}
+	}
+	return count
+}
+
 func (router *ScoreBasedRouter) getConnWrapper(conn RedirectableConn) *glist.Element[*connWrapper] {
 	return conn.Value(_routerKey).(*glist.Element[*connWrapper])
 }

pkg/balance/router/router_score_test.go

@@ -322,11 +322,14 @@ func TestNoBackends(t *testing.T) {
 	conn := tester.createConn()
 	backend := tester.simpleRoute(conn)
 	require.True(t, backend == nil || reflect.ValueOf(backend).IsNil())
+	require.Equal(t, 0, tester.router.HealthyBackendCount())
 	tester.addBackends(1)
+	require.Equal(t, 1, tester.router.HealthyBackendCount())
 	tester.addConnections(10)
 	tester.killBackends(1)
 	backend = tester.simpleRoute(conn)
 	require.True(t, backend == nil || reflect.ValueOf(backend).IsNil())
+	require.Equal(t, 0, tester.router.HealthyBackendCount())
 }
 
 // Test that the backends returned by the BackendSelector are complete and different.

pkg/balance/router/router_static.go

@@ -45,6 +45,10 @@ func (r *StaticRouter) GetBackendSelector() BackendSelector {
 	}
 }
 
+func (r *StaticRouter) HealthyBackendCount() int {
+	return len(r.backends)
+}
+
 func (r *StaticRouter) RefreshBackend() {}
 
 func (r *StaticRouter) RedirectConnections() error {

pkg/manager/namespace/manager.go

@@ -22,7 +22,19 @@ import (
 	"go.uber.org/zap"
 )
 
-type NamespaceManager struct {
+type NamespaceManager interface {
+	Init(logger *zap.Logger, nscs []*config.Namespace, tpFetcher observer.TopologyFetcher,
+		promFetcher metricsreader.PromInfoFetcher, httpCli *http.Client, cfgMgr *mconfig.ConfigManager,
+		metricsReader metricsreader.MetricsReader) error
+	CommitNamespaces(nss []*config.Namespace, nssDelete []bool) error
+	GetNamespace(nm string) (*Namespace, bool)
+	GetNamespaceByUser(user string) (*Namespace, bool)
+	RedirectConnections() []error
+	Ready() bool
+	Close() error
+}
+
+type namespaceManager struct {
 	sync.RWMutex
 	nsm           map[string]*Namespace
 	tpFetcher     observer.TopologyFetcher
@@ -33,17 +45,17 @@ type NamespaceManager struct {
 	cfgMgr        *mconfig.ConfigManager
 }
 
-func NewNamespaceManager() *NamespaceManager {
-	return &NamespaceManager{}
+func NewNamespaceManager() *namespaceManager {
+	return &namespaceManager{}
 }
 
-func (mgr *NamespaceManager) buildNamespace(cfg *config.Namespace) (*Namespace, error) {
+func (mgr *namespaceManager) buildNamespace(cfg *config.Namespace) (*Namespace, error) {
 	logger := mgr.logger.With(zap.String("namespace", cfg.Namespace))
 
 	// init BackendFetcher
 	var fetcher observer.BackendFetcher
 	healthCheckCfg := config.NewDefaultHealthCheckConfig()
-	if !reflect.ValueOf(mgr.tpFetcher).IsNil() {
+	if mgr.tpFetcher != nil && !reflect.ValueOf(mgr.tpFetcher).IsNil() {
 		fetcher = observer.NewPDFetcher(mgr.tpFetcher, logger.Named("be_fetcher"), healthCheckCfg)
 	} else {
 		fetcher = observer.NewStaticFetcher(cfg.Backend.Instances)
@@ -65,7 +77,7 @@ func (mgr *NamespaceManager) buildNamespace(cfg *config.Namespace) (*Namespace,
 	}, nil
 }
 
-func (mgr *NamespaceManager) CommitNamespaces(nss []*config.Namespace, nss_delete []bool) error {
+func (mgr *namespaceManager) CommitNamespaces(nss []*config.Namespace, nssDelete []bool) error {
 	nsm := make(map[string]*Namespace)
 	mgr.RLock()
 	for k, v := range mgr.nsm {
@@ -74,7 +86,7 @@ func (mgr *NamespaceManager) CommitNamespaces(nss []*config.Namespace, nss_delet
 	mgr.RUnlock()
 
 	for i, nsc := range nss {
-		if nss_delete != nil && nss_delete[i] {
+		if nssDelete != nil && nssDelete[i] {
 			delete(nsm, nsc.Namespace)
 			continue
 		}
@@ -92,7 +104,7 @@ func (mgr *NamespaceManager) CommitNamespaces(nss []*config.Namespace, nss_delet
 	return nil
 }
 
-func (mgr *NamespaceManager) Init(logger *zap.Logger, nscs []*config.Namespace, tpFetcher observer.TopologyFetcher,
+func (mgr *namespaceManager) Init(logger *zap.Logger, nscs []*config.Namespace, tpFetcher observer.TopologyFetcher,
 	promFetcher metricsreader.PromInfoFetcher, httpCli *http.Client, cfgMgr *mconfig.ConfigManager,
 	metricsReader metricsreader.MetricsReader) error {
 	mgr.Lock()
@@ -106,15 +118,15 @@ func (mgr *NamespaceManager) Init(logger *zap.Logger, nscs []*config.Namespace,
 	return mgr.CommitNamespaces(nscs, nil)
 }
 
-func (mgr *NamespaceManager) GetNamespace(nm string) (*Namespace, bool) {
+func (mgr *namespaceManager) GetNamespace(nm string) (*Namespace, bool) {
 	mgr.RLock()
 	defer mgr.RUnlock()
 
 	ns, ok := mgr.nsm[nm]
 	return ns, ok
 }
 
-func (mgr *NamespaceManager) GetNamespaceByUser(user string) (*Namespace, bool) {
+func (mgr *namespaceManager) GetNamespaceByUser(user string) (*Namespace, bool) {
 	mgr.RLock()
 	defer mgr.RUnlock()
 
@@ -126,7 +138,7 @@ func (mgr *NamespaceManager) GetNamespaceByUser(user string) (*Namespace, bool)
 	return nil, false
 }
 
-func (mgr *NamespaceManager) RedirectConnections() []error {
+func (mgr *namespaceManager) RedirectConnections() []error {
 	mgr.RLock()
 	defer mgr.RUnlock()
 
@@ -140,7 +152,21 @@ func (mgr *NamespaceManager) RedirectConnections() []error {
 	return errs
 }
 
-func (mgr *NamespaceManager) Close() error {
+func (mgr *namespaceManager) Ready() bool {
+	mgr.RLock()
+	defer mgr.RUnlock()
+	if len(mgr.nsm) == 0 {
+		return false
+	}
+	for _, ns := range mgr.nsm {
+		if ns.GetRouter().HealthyBackendCount() <= 0 {
+			return false
+		}
+	}
+	return true
+}
+
+func (mgr *namespaceManager) Close() error {
 	mgr.RLock()
 	for _, ns := range mgr.nsm {
 		ns.Close()

pkg/manager/namespace/manager_test.go

@@ -0,0 +1,32 @@
+// Copyright 2024 PingCAP, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+package namespace
+
+import (
+	"testing"
+
+	"github.com/pingcap/tiproxy/pkg/balance/router"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap"
+)
+
+func TestReady(t *testing.T) {
+	nsMgr := NewNamespaceManager()
+	require.NoError(t, nsMgr.Init(zap.NewNop(), nil, nil, nil, nil, nil, nil))
+	require.False(t, nsMgr.Ready())
+
+	rt := router.NewStaticRouter([]string{})
+	nsMgr.nsm = map[string]*Namespace{
+		"test": {
+			router: rt,
+		},
+	}
+	require.False(t, nsMgr.Ready())
+
+	rt = router.NewStaticRouter([]string{"127.0.0.1:4000"})
+	ns, ok := nsMgr.GetNamespace("test")
+	require.True(t, ok)
+	ns.router = rt
+	require.True(t, nsMgr.Ready())
+}

pkg/proxy/backend/handshake_handler.go

@@ -52,10 +52,10 @@ type HandshakeHandler interface {
 }
 
 type DefaultHandshakeHandler struct {
-	nsManager *namespace.NamespaceManager
+	nsManager namespace.NamespaceManager
 }
 
-func NewDefaultHandshakeHandler(nsManager *namespace.NamespaceManager) *DefaultHandshakeHandler {
+func NewDefaultHandshakeHandler(nsManager namespace.NamespaceManager) *DefaultHandshakeHandler {
 	return &DefaultHandshakeHandler{
 		nsManager: nsManager,
 	}

pkg/server/api/debug.go

@@ -13,7 +13,7 @@ import (
 
 func (h *Server) DebugHealth(c *gin.Context) {
 	status := http.StatusOK
-	if h.isClosing.Load() {
+	if h.isClosing.Load() || !h.mgr.NsMgr.Ready() {
 		status = http.StatusBadGateway
 	}
 	c.JSON(status, config.HealthInfo{

pkg/server/api/debug_test.go

@@ -24,6 +24,12 @@ func TestDebug(t *testing.T) {
 		require.Equal(t, http.StatusOK, r.StatusCode)
 	})
 
+	server.mgr.NsMgr.(*mockNamespaceManager).success.Store(false)
+	doHTTP(t, http.MethodGet, "/api/debug/health", httpOpts{}, func(t *testing.T, r *http.Response) {
+		require.Equal(t, http.StatusBadGateway, r.StatusCode)
+	})
+
+	server.mgr.NsMgr.(*mockNamespaceManager).success.Store(true)
 	doHTTP(t, http.MethodGet, "/api/debug/health", httpOpts{}, func(t *testing.T, r *http.Response) {
 		require.Equal(t, http.StatusOK, r.StatusCode)
 	})

pkg/server/api/mock_test.go

@@ -0,0 +1,76 @@
+// Copyright 2024 PingCAP, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+package api
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+
+	"github.com/pingcap/tiproxy/lib/config"
+	"github.com/pingcap/tiproxy/pkg/balance/metricsreader"
+	"github.com/pingcap/tiproxy/pkg/balance/observer"
+	mconfig "github.com/pingcap/tiproxy/pkg/manager/config"
+	"github.com/pingcap/tiproxy/pkg/manager/namespace"
+	"github.com/pingcap/tiproxy/pkg/util/http"
+	"go.uber.org/zap"
+)
+
+var _ namespace.NamespaceManager = (*mockNamespaceManager)(nil)
+
+type mockNamespaceManager struct {
+	success atomic.Bool
+}
+
+func newMockNamespaceManager() *mockNamespaceManager {
+	mgr := &mockNamespaceManager{}
+	mgr.success.Store(true)
+	return mgr
+}
+
+func (m *mockNamespaceManager) Init(_ *zap.Logger, _ []*config.Namespace, _ observer.TopologyFetcher,
+	_ metricsreader.PromInfoFetcher, _ *http.Client, _ *mconfig.ConfigManager, _ metricsreader.MetricsReader) error {
+	return nil
+}
+
+func (m *mockNamespaceManager) GetNamespace(_ string) (*namespace.Namespace, bool) {
+	return nil, false
+}
+
+func (m *mockNamespaceManager) GetNamespaceByUser(_ string) (*namespace.Namespace, bool) {
+	return nil, false
+}
+
+func (m *mockNamespaceManager) SetNamespace(_ context.Context, _ string, _ *config.Namespace) error {
+	if m.success.Load() {
+		return nil
+	}
+	return errors.New("mock error")
+}
+
+func (m *mockNamespaceManager) GetConfigChecksum() string {
+	return ""
+}
+
+func (m *mockNamespaceManager) Ready() bool {
+	return m.success.Load()
+}
+
+func (m *mockNamespaceManager) RedirectConnections() []error {
+	if m.success.Load() {
+		return nil
+	}
+	return []error{errors.New("mock error")}
+}
+
+func (m *mockNamespaceManager) Close() error {
+	return nil
+}
+
+func (m *mockNamespaceManager) CommitNamespaces(_ []*config.Namespace, _ []bool) error {
+	if m.success.Load() {
+		return nil
+	}
+	return errors.New("mock error")
+}

pkg/server/api/namespace_test.go

@@ -13,7 +13,7 @@ import (
 )
 
 func TestNamespace(t *testing.T) {
-	_, doHTTP := createServer(t)
+	srv, doHTTP := createServer(t)
 
 	// test list
 	doHTTP(t, http.MethodGet, "/api/admin/namespace", httpOpts{}, func(t *testing.T, r *http.Response) {
@@ -51,7 +51,8 @@ func TestNamespace(t *testing.T) {
 	doHTTP(t, http.MethodPost, "/api/admin/namespace/commit?namespace=xx", httpOpts{}, func(t *testing.T, r *http.Response) {
 		require.Equal(t, http.StatusInternalServerError, r.StatusCode)
 	})
+	srv.mgr.NsMgr.(*mockNamespaceManager).success.Store(true)
 	doHTTP(t, http.MethodPost, "/api/admin/namespace/commit", httpOpts{}, func(t *testing.T, r *http.Response) {
-		require.Equal(t, http.StatusInternalServerError, r.StatusCode)
+		require.Equal(t, http.StatusOK, r.StatusCode)
 	})
 }

pkg/server/api/server.go

@@ -45,7 +45,7 @@ type HTTPHandler interface {
 
 type Managers struct {
 	CfgMgr        *mgrcfg.ConfigManager
-	NsMgr         *mgrns.NamespaceManager
+	NsMgr         mgrns.NamespaceManager
 	CertMgr       *mgrcrt.CertManager
 	BackendReader BackendReader
 	ReplayJobMgr  mgrrp.JobManager

pkg/server/api/server_test.go

@@ -14,7 +14,6 @@ import (
 	"github.com/pingcap/tiproxy/lib/util/logger"
 	mgrcrt "github.com/pingcap/tiproxy/pkg/manager/cert"
 	mgrcfg "github.com/pingcap/tiproxy/pkg/manager/config"
-	mgrns "github.com/pingcap/tiproxy/pkg/manager/namespace"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/atomic"
 	"google.golang.org/grpc"
@@ -33,11 +32,12 @@ func createServer(t *testing.T) (*Server, func(t *testing.T, method string, path
 	require.NoError(t, cfgmgr.Init(context.Background(), lg, "", ""))
 	crtmgr := mgrcrt.NewCertManager()
 	require.NoError(t, crtmgr.Init(cfgmgr.GetConfig(), lg, cfgmgr.WatchConfig()))
+	nsMgr := newMockNamespaceManager()
 	srv, err := NewServer(config.API{
 		Addr: "0.0.0.0:0",
 	}, lg, Managers{
 		CfgMgr:        cfgmgr,
-		NsMgr:         mgrns.NewNamespaceManager(),
+		NsMgr:         nsMgr,
 		CertMgr:       crtmgr,
 		BackendReader: &mockBackendReader{},
 		ReplayJobMgr:  &mockReplayJobManager{},

pkg/server/server.go

@@ -37,7 +37,7 @@ type Server struct {
 	wg waitgroup.WaitGroup
 	// managers
 	configManager    *mgrcfg.ConfigManager
-	namespaceManager *mgrns.NamespaceManager
+	namespaceManager mgrns.NamespaceManager
 	metricsManager   *metrics.MetricsManager
 	loggerManager    *logger.LoggerManager
 	certManager      *cert.CertManager