VOL-2970 - Improved readability & traceability of startup code.
Changed Start() function to implement majority of the startup functionality, with less helpers. Start() also defines local variables for each component created, to avoid accidentally using a component that isn't ready.
Also merged the rwCore into the Core.
Also changed Core to cancel a local context to on shutdown, and then wait for shutdown to complete.
Change-Id: I285e8486773476531e20ec352ff85a1b145432bf
diff --git a/rw_core/core/core.go b/rw_core/core/core.go
index 7cf9f98..0dbecc8 100644
--- a/rw_core/core/core.go
+++ b/rw_core/core/core.go
@@ -18,7 +18,7 @@
import (
"context"
- "sync"
+ "strconv"
"time"
"github.com/opencord/voltha-go/db/model"
@@ -26,446 +26,150 @@
"github.com/opencord/voltha-go/rw_core/core/adapter"
"github.com/opencord/voltha-go/rw_core/core/api"
"github.com/opencord/voltha-go/rw_core/core/device"
+ conf "github.com/opencord/voltha-lib-go/v3/pkg/config"
"github.com/opencord/voltha-lib-go/v3/pkg/db"
- "github.com/opencord/voltha-lib-go/v3/pkg/db/kvstore"
grpcserver "github.com/opencord/voltha-lib-go/v3/pkg/grpc"
"github.com/opencord/voltha-lib-go/v3/pkg/kafka"
"github.com/opencord/voltha-lib-go/v3/pkg/log"
"github.com/opencord/voltha-lib-go/v3/pkg/probe"
"github.com/opencord/voltha-protos/v3/go/voltha"
"google.golang.org/grpc"
- "google.golang.org/grpc/codes"
- "google.golang.org/grpc/status"
)
// Core represent read,write core attributes
type Core struct {
- instanceID string
- deviceMgr *device.Manager
- logicalDeviceMgr *device.LogicalManager
- grpcServer *grpcserver.GrpcServer
- grpcNBIAPIHandler *api.NBIHandler
- adapterMgr *adapter.Manager
- config *config.RWCoreFlags
- kmp kafka.InterContainerProxy
- clusterDataProxy *model.Proxy
- localDataProxy *model.Proxy
- exitChannel chan struct{}
- stopOnce sync.Once
- kvClient kvstore.Client
- backend db.Backend
- kafkaClient kafka.Client
+ shutdown context.CancelFunc
+ stopped chan struct{}
}
// NewCore creates instance of rw core
-func NewCore(ctx context.Context, id string, cf *config.RWCoreFlags, kvClient kvstore.Client, kafkaClient kafka.Client) *Core {
- var core Core
- core.instanceID = id
- core.exitChannel = make(chan struct{})
- core.config = cf
- core.kvClient = kvClient
- core.kafkaClient = kafkaClient
-
- // Configure backend to push Liveness Status at least every (cf.LiveProbeInterval / 2) seconds
- // so as to avoid trigger of Liveness check (due to Liveness timeout) when backend is alive
- livenessChannelInterval := cf.LiveProbeInterval / 2
-
- // Setup the KV store
- core.backend = db.Backend{
- Client: kvClient,
- StoreType: cf.KVStoreType,
- Host: cf.KVStoreHost,
- Port: cf.KVStorePort,
- Timeout: cf.KVStoreTimeout,
- LivenessChannelInterval: livenessChannelInterval,
- PathPrefix: cf.KVStoreDataPrefix}
- return &core
-}
-
-// Start brings up core services
-func (core *Core) Start(ctx context.Context) error {
-
+func NewCore(ctx context.Context, id string, cf *config.RWCoreFlags) *Core {
// If the context has a probe then fetch it and register our services
- var p *probe.Probe
- if value := ctx.Value(probe.ProbeContextKey); value != nil {
- if _, ok := value.(*probe.Probe); ok {
- p = value.(*probe.Probe)
- p.RegisterService(
- "message-bus",
- "kv-store",
- "device-manager",
- "logical-device-manager",
- "adapter-manager",
- "grpc-service",
- )
- }
- }
-
- logger.Info("starting-core-services", log.Fields{"coreId": core.instanceID})
-
- // Wait until connection to KV Store is up
- if err := core.waitUntilKVStoreReachableOrMaxTries(ctx, core.config.MaxConnectionRetries, core.config.ConnectionRetryInterval); err != nil {
- logger.Fatal("Unable-to-connect-to-KV-store")
- }
- if p != nil {
- p.UpdateStatus("kv-store", probe.ServiceStatusRunning)
- }
-
- endpointMgr := kafka.NewEndpointManager(&core.backend)
-
- core.clusterDataProxy = model.NewProxy(&core.backend, "/")
- core.localDataProxy = model.NewProxy(&core.backend, "/")
-
- // core.kmp must be created before deviceMgr and adapterMgr, as they will make
- // private copies of the poiner to core.kmp.
- core.initKafkaManager(ctx)
-
- logger.Debugw("values", log.Fields{"kmp": core.kmp})
- core.adapterMgr = adapter.NewAdapterManager(core.clusterDataProxy, core.instanceID, core.kafkaClient)
- core.deviceMgr, core.logicalDeviceMgr = device.NewManagers(core.clusterDataProxy, core.adapterMgr, core.kmp, endpointMgr, core.config.CorePairTopic, core.instanceID, core.config.DefaultCoreTimeout)
-
- // Start the KafkaManager. This must be done after the deviceMgr, adapterMgr, and
- // logicalDeviceMgr have been created, as once the kmp is started, it will register
- // the above with the kmp.
-
- go core.startKafkaManager(ctx,
- core.config.ConnectionRetryInterval,
- core.config.LiveProbeInterval,
- core.config.NotLiveProbeInterval)
-
- go core.startDeviceManager(ctx)
- go core.startLogicalDeviceManager(ctx)
- go core.startGRPCService(ctx)
- go core.startAdapterManager(ctx)
- go core.monitorKvstoreLiveness(ctx)
-
- logger.Info("core-services-started")
- return nil
-}
-
-// Stop brings down core services
-func (core *Core) Stop(ctx context.Context) {
- core.stopOnce.Do(func() {
- logger.Info("stopping-adaptercore")
- // Signal to the KVStoreMonitor that we are stopping.
- close(core.exitChannel)
- // Stop all the started services
- if core.grpcServer != nil {
- core.grpcServer.Stop()
- }
- if core.logicalDeviceMgr != nil {
- core.logicalDeviceMgr.Stop(ctx)
- }
- if core.deviceMgr != nil {
- core.deviceMgr.Stop(ctx)
- }
- if core.kmp != nil {
- core.kmp.Stop()
- }
- logger.Info("adaptercore-stopped")
- })
-}
-
-//startGRPCService creates the grpc service handlers, registers it to the grpc server and starts the server
-func (core *Core) startGRPCService(ctx context.Context) {
- // create an insecure gserver server
- core.grpcServer = grpcserver.NewGrpcServer(core.config.GrpcHost, core.config.GrpcPort, nil, false, probe.GetProbeFromContext(ctx))
- logger.Info("grpc-server-created")
-
- core.grpcNBIAPIHandler = api.NewNBIHandler(core.deviceMgr, core.logicalDeviceMgr, core.adapterMgr)
- logger.Infow("grpc-handler", log.Fields{"core_binding_key": core.config.CoreBindingKey})
- // Create a function to register the core GRPC service with the GRPC server
- f := func(gs *grpc.Server) {
- voltha.RegisterVolthaServiceServer(
- gs,
- core.grpcNBIAPIHandler,
+ if p := probe.GetProbeFromContext(ctx); p != nil {
+ p.RegisterService(
+ "message-bus",
+ "kv-store",
+ "adapter-manager",
+ "grpc-service",
)
}
- core.grpcServer.AddService(f)
+ // new threads will be given a new cancelable context, so that they can be aborted later when Stop() is called
+ shutdownCtx, cancelCtx := context.WithCancel(ctx)
+
+ core := &Core{shutdown: cancelCtx, stopped: make(chan struct{})}
+ go core.start(shutdownCtx, id, cf)
+ return core
+}
+
+func (core *Core) start(ctx context.Context, id string, cf *config.RWCoreFlags) {
+ logger.Info("starting-core-services", log.Fields{"coreId": id})
+
+ // deferred functions are used to run cleanup
+ // failing partway will stop anything that's been started
+ defer close(core.stopped)
+ defer core.shutdown()
+
+ logger.Info("Starting RW Core components")
+
+ // setup kv client
+ logger.Debugw("create-kv-client", log.Fields{"kvstore": cf.KVStoreType})
+ kvClient, err := newKVClient(cf.KVStoreType, cf.KVStoreHost+":"+strconv.Itoa(cf.KVStorePort), cf.KVStoreTimeout)
+ if err != nil {
+ logger.Fatal(err)
+ }
+ defer stopKVClient(context.Background(), kvClient)
+
+ // sync logging config with kv store
+ cm := conf.NewConfigManager(kvClient, cf.KVStoreType, cf.KVStoreHost, cf.KVStorePort, cf.KVStoreTimeout)
+ go conf.StartLogLevelConfigProcessing(cm, ctx)
+
+ backend := &db.Backend{
+ Client: kvClient,
+ StoreType: cf.KVStoreType,
+ Host: cf.KVStoreHost,
+ Port: cf.KVStorePort,
+ Timeout: cf.KVStoreTimeout,
+ // Configure backend to push Liveness Status at least every (cf.LiveProbeInterval / 2) seconds
+ // so as to avoid trigger of Liveness check (due to Liveness timeout) when backend is alive
+ LivenessChannelInterval: cf.LiveProbeInterval / 2,
+ PathPrefix: cf.KVStoreDataPrefix,
+ }
+
+ // wait until connection to KV Store is up
+ if err := waitUntilKVStoreReachableOrMaxTries(ctx, kvClient, cf.MaxConnectionRetries, cf.ConnectionRetryInterval); err != nil {
+ logger.Fatal("Unable-to-connect-to-KV-store")
+ }
+ go monitorKVStoreLiveness(ctx, backend, cf.LiveProbeInterval, cf.NotLiveProbeInterval)
+
+ // create kafka client
+ kafkaClient := kafka.NewSaramaClient(
+ kafka.Host(cf.KafkaAdapterHost),
+ kafka.Port(cf.KafkaAdapterPort),
+ kafka.ConsumerType(kafka.GroupCustomer),
+ kafka.ProducerReturnOnErrors(true),
+ kafka.ProducerReturnOnSuccess(true),
+ kafka.ProducerMaxRetries(6),
+ kafka.NumPartitions(3),
+ kafka.ConsumerGroupName(id),
+ kafka.ConsumerGroupPrefix(id),
+ kafka.AutoCreateTopic(true),
+ kafka.ProducerFlushFrequency(5),
+ kafka.ProducerRetryBackoff(time.Millisecond*30),
+ kafka.LivenessChannelInterval(cf.LiveProbeInterval/2),
+ )
+ // defer kafkaClient.Stop()
+
+ // create kv proxy
+ proxy := model.NewProxy(backend, "/")
+
+ // load adapters & device types while other things are starting
+ adapterMgr := adapter.NewAdapterManager(proxy, id, kafkaClient)
+ go adapterMgr.Start(ctx)
+
+ // connect to kafka, then wait until reachable and publisher/consumer created
+ // core.kmp must be created before deviceMgr and adapterMgr
+ kmp, err := startKafkInterContainerProxy(ctx, kafkaClient, cf.KafkaAdapterHost, cf.KafkaAdapterPort, cf.CoreTopic, cf.AffinityRouterTopic, cf.ConnectionRetryInterval)
+ if err != nil {
+ logger.Warn("Failed to setup kafka connection")
+ return
+ }
+ defer kmp.Stop()
+ go monitorKafkaLiveness(ctx, kmp, cf.LiveProbeInterval, cf.NotLiveProbeInterval)
+
+ // create the core of the system, the device managers
+ endpointMgr := kafka.NewEndpointManager(backend)
+ deviceMgr, logicalDeviceMgr := device.NewManagers(proxy, adapterMgr, kmp, endpointMgr, cf.CorePairTopic, id, cf.DefaultCoreTimeout)
+
+ // register kafka RPC handler
+ registerAdapterRequestHandlers(kmp, deviceMgr, adapterMgr, cf.CoreTopic, cf.CorePairTopic)
+
+ // start gRPC handler
+ grpcServer := grpcserver.NewGrpcServer(cf.GrpcHost, cf.GrpcPort, nil, false, probe.GetProbeFromContext(ctx))
+ go startGRPCService(ctx, grpcServer, api.NewNBIHandler(deviceMgr, logicalDeviceMgr, adapterMgr))
+ defer grpcServer.Stop()
+
+ // wait for core to be stopped, via Stop() or context cancellation, before running deferred functions
+ <-ctx.Done()
+}
+
+// Stop brings down core services
+func (core *Core) Stop() {
+ core.shutdown()
+ <-core.stopped
+}
+
+// startGRPCService creates the grpc service handlers, registers it to the grpc server and starts the server
+func startGRPCService(ctx context.Context, server *grpcserver.GrpcServer, handler voltha.VolthaServiceServer) {
+ logger.Info("grpc-server-created")
+
+ server.AddService(func(gs *grpc.Server) { voltha.RegisterVolthaServiceServer(gs, handler) })
logger.Info("grpc-service-added")
- /*
- * Start the GRPC server
- *
- * This is a bit sub-optimal here as the grpcServer.Start call does not return (blocks)
- * until something fails, but we want to send a "start" status update. As written this
- * means that we are actually sending the "start" status update before the server is
- * started, which means it is possible that the status is "running" before it actually is.
- *
- * This means that there is a small window in which the core could return its status as
- * ready, when it really isn't.
- */
probe.UpdateStatusFromContext(ctx, "grpc-service", probe.ServiceStatusRunning)
logger.Info("grpc-server-started")
- core.grpcServer.Start(ctx)
+ // Note that there is a small window here in which the core could return its status as ready,
+ // when it really isn't. This is unlikely to cause issues, as the delay is incredibly short.
+ server.Start(ctx)
probe.UpdateStatusFromContext(ctx, "grpc-service", probe.ServiceStatusStopped)
}
-
-// Initialize the kafka manager, but we will start it later
-func (core *Core) initKafkaManager(ctx context.Context) {
- logger.Infow("initialize-kafka-manager", log.Fields{"host": core.config.KafkaAdapterHost,
- "port": core.config.KafkaAdapterPort, "topic": core.config.CoreTopic})
-
- probe.UpdateStatusFromContext(ctx, "message-bus", probe.ServiceStatusPreparing)
-
- // create the proxy
- core.kmp = kafka.NewInterContainerProxy(
- kafka.InterContainerHost(core.config.KafkaAdapterHost),
- kafka.InterContainerPort(core.config.KafkaAdapterPort),
- kafka.MsgClient(core.kafkaClient),
- kafka.DefaultTopic(&kafka.Topic{Name: core.config.CoreTopic}),
- kafka.DeviceDiscoveryTopic(&kafka.Topic{Name: core.config.AffinityRouterTopic}))
-
- probe.UpdateStatusFromContext(ctx, "message-bus", probe.ServiceStatusPrepared)
-}
-
-/*
- * KafkaMonitorThread
- *
- * Responsible for starting the Kafka Interadapter Proxy and monitoring its liveness
- * state.
- *
- * Any producer that fails to send will cause KafkaInterContainerProxy to
- * post a false event on its liveness channel. Any producer that succeeds in sending
- * will cause KafkaInterContainerProxy to post a true event on its liveness
- * channel. Group receivers also update liveness state, and a receiver will typically
- * indicate a loss of liveness within 3-5 seconds of Kafka going down. Receivers
- * only indicate restoration of liveness if a message is received. During normal
- * operation, messages will be routinely produced and received, automatically
- * indicating liveness state. These routine liveness indications are rate-limited
- * inside sarama_client.
- *
- * This thread monitors the status of KafkaInterContainerProxy's liveness and pushes
- * that state to the core's readiness probes. If no liveness event has been seen
- * within a timeout, then the thread will make an attempt to produce a "liveness"
- * message, which will in turn trigger a liveness event on the liveness channel, true
- * or false depending on whether the attempt succeeded.
- *
- * The gRPC server in turn monitors the state of the readiness probe and will
- * start issuing UNAVAILABLE response while the probe is not ready.
- *
- * startupRetryInterval -- interval between attempts to start
- * liveProbeInterval -- interval between liveness checks when in a live state
- * notLiveProbeInterval -- interval between liveness checks when in a notLive state
- *
- * liveProbeInterval and notLiveProbeInterval can be configured separately,
- * though the current default is that both are set to 60 seconds.
- */
-
-func (core *Core) startKafkaManager(ctx context.Context, startupRetryInterval time.Duration, liveProbeInterval time.Duration, notLiveProbeInterval time.Duration) {
- logger.Infow("starting-kafka-manager-thread", log.Fields{"host": core.config.KafkaAdapterHost,
- "port": core.config.KafkaAdapterPort, "topic": core.config.CoreTopic})
-
- started := false
- for !started {
- // If we haven't started yet, then try to start
- logger.Infow("starting-kafka-proxy", log.Fields{})
- if err := core.kmp.Start(); err != nil {
- // We failed to start. Delay and then try again later.
- // Don't worry about liveness, as we can't be live until we've started.
- probe.UpdateStatusFromContext(ctx, "message-bus", probe.ServiceStatusNotReady)
- logger.Infow("error-starting-kafka-messaging-proxy", log.Fields{"error": err})
- time.Sleep(startupRetryInterval)
- } else {
- // We started. We only need to do this once.
- // Next we'll fall through and start checking liveness.
- logger.Infow("started-kafka-proxy", log.Fields{})
-
- // cannot do this until after the kmp is started
- if err := core.registerAdapterRequestHandlers(ctx, core.instanceID, core.deviceMgr, core.logicalDeviceMgr, core.adapterMgr, core.clusterDataProxy, core.localDataProxy); err != nil {
- logger.Fatal("Failure-registering-adapterRequestHandler")
- }
-
- started = true
- }
- }
-
- logger.Info("started-kafka-message-proxy")
-
- livenessChannel := core.kmp.EnableLivenessChannel(true)
-
- logger.Info("enabled-kafka-liveness-channel")
-
- timeout := liveProbeInterval
- for {
- timeoutTimer := time.NewTimer(timeout)
- select {
- case liveness := <-livenessChannel:
- logger.Infow("kafka-manager-thread-liveness-event", log.Fields{"liveness": liveness})
- // there was a state change in Kafka liveness
- if !liveness {
- probe.UpdateStatusFromContext(ctx, "message-bus", probe.ServiceStatusNotReady)
-
- if core.grpcServer != nil {
- logger.Info("kafka-manager-thread-set-server-notready")
- }
-
- // retry frequently while life is bad
- timeout = notLiveProbeInterval
- } else {
- probe.UpdateStatusFromContext(ctx, "message-bus", probe.ServiceStatusRunning)
-
- if core.grpcServer != nil {
- logger.Info("kafka-manager-thread-set-server-ready")
- }
-
- // retry infrequently while life is good
- timeout = liveProbeInterval
- }
- if !timeoutTimer.Stop() {
- <-timeoutTimer.C
- }
- case <-timeoutTimer.C:
- logger.Info("kafka-proxy-liveness-recheck")
- // send the liveness probe in a goroutine; we don't want to deadlock ourselves as
- // the liveness probe may wait (and block) writing to our channel.
- go func() {
- err := core.kmp.SendLiveness()
- if err != nil {
- // Catch possible error case if sending liveness after Sarama has been stopped.
- logger.Warnw("error-kafka-send-liveness", log.Fields{"error": err})
- }
- }()
- }
- }
-}
-
-// waitUntilKVStoreReachableOrMaxTries will wait until it can connect to a KV store or until maxtries has been reached
-func (core *Core) waitUntilKVStoreReachableOrMaxTries(ctx context.Context, maxRetries int, retryInterval time.Duration) error {
- logger.Infow("verifying-KV-store-connectivity", log.Fields{"host": core.config.KVStoreHost,
- "port": core.config.KVStorePort, "retries": maxRetries, "retryInterval": retryInterval})
- count := 0
- for {
- if !core.kvClient.IsConnectionUp(ctx) {
- logger.Info("KV-store-unreachable")
- if maxRetries != -1 {
- if count >= maxRetries {
- return status.Error(codes.Unavailable, "kv store unreachable")
- }
- }
- count++
- // Take a nap before retrying
- time.Sleep(retryInterval)
- logger.Infow("retry-KV-store-connectivity", log.Fields{"retryCount": count, "maxRetries": maxRetries, "retryInterval": retryInterval})
-
- } else {
- break
- }
- }
- logger.Info("KV-store-reachable")
- return nil
-}
-
-func (core *Core) registerAdapterRequestHandlers(ctx context.Context, coreInstanceID string, dMgr *device.Manager,
- ldMgr *device.LogicalManager, aMgr *adapter.Manager, cdProxy *model.Proxy, ldProxy *model.Proxy,
-) error {
- requestProxy := api.NewAdapterRequestHandlerProxy(coreInstanceID, dMgr, aMgr, cdProxy, ldProxy,
- core.config.LongRunningRequestTimeout, core.config.DefaultRequestTimeout)
-
- // Register the broadcast topic to handle any core-bound broadcast requests
- if err := core.kmp.SubscribeWithRequestHandlerInterface(kafka.Topic{Name: core.config.CoreTopic}, requestProxy); err != nil {
- logger.Fatalw("Failed-registering-broadcast-handler", log.Fields{"topic": core.config.CoreTopic})
- return err
- }
-
- // Register the core-pair topic to handle core-bound requests destined to the core pair
- if err := core.kmp.SubscribeWithDefaultRequestHandler(kafka.Topic{Name: core.config.CorePairTopic}, kafka.OffsetNewest); err != nil {
- logger.Fatalw("Failed-registering-pair-handler", log.Fields{"topic": core.config.CorePairTopic})
- return err
- }
-
- logger.Info("request-handler-registered")
- return nil
-}
-
-func (core *Core) startDeviceManager(ctx context.Context) {
- logger.Info("DeviceManager-Starting...")
- core.deviceMgr.Start(ctx)
- logger.Info("DeviceManager-Started")
-}
-
-func (core *Core) startLogicalDeviceManager(ctx context.Context) {
- logger.Info("Logical-DeviceManager-Starting...")
- core.logicalDeviceMgr.Start(ctx)
- logger.Info("Logical-DeviceManager-Started")
-}
-
-func (core *Core) startAdapterManager(ctx context.Context) {
- logger.Info("Adapter-Manager-Starting...")
- err := core.adapterMgr.Start(ctx)
- if err != nil {
- logger.Fatalf("failed-to-start-adapter-manager: error %v ", err)
- }
- logger.Info("Adapter-Manager-Started")
-}
-
-/*
-* Thread to monitor kvstore Liveness (connection status)
-*
-* This function constantly monitors Liveness State of kvstore as reported
-* periodically by backend and updates the Status of kv-store service registered
-* with rw_core probe.
-*
-* If no liveness event has been seen within a timeout, then the thread will
-* perform a "liveness" check attempt, which will in turn trigger a liveness event on
-* the liveness channel, true or false depending on whether the attempt succeeded.
-*
-* The gRPC server in turn monitors the state of the readiness probe and will
-* start issuing UNAVAILABLE response while the probe is not ready.
- */
-func (core *Core) monitorKvstoreLiveness(ctx context.Context) {
- logger.Info("start-monitoring-kvstore-liveness")
-
- // Instruct backend to create Liveness channel for transporting state updates
- livenessChannel := core.backend.EnableLivenessChannel()
-
- logger.Debug("enabled-kvstore-liveness-channel")
-
- // Default state for kvstore is alive for rw_core
- timeout := core.config.LiveProbeInterval
-loop:
- for {
- timeoutTimer := time.NewTimer(timeout)
- select {
-
- case liveness := <-livenessChannel:
- logger.Debugw("received-liveness-change-notification", log.Fields{"liveness": liveness})
-
- if !liveness {
- probe.UpdateStatusFromContext(ctx, "kv-store", probe.ServiceStatusNotReady)
-
- if core.grpcServer != nil {
- logger.Info("kvstore-set-server-notready")
- }
-
- timeout = core.config.NotLiveProbeInterval
-
- } else {
- probe.UpdateStatusFromContext(ctx, "kv-store", probe.ServiceStatusRunning)
-
- if core.grpcServer != nil {
- logger.Info("kvstore-set-server-ready")
- }
-
- timeout = core.config.LiveProbeInterval
- }
-
- if !timeoutTimer.Stop() {
- <-timeoutTimer.C
- }
-
- case <-core.exitChannel:
- break loop
-
- case <-timeoutTimer.C:
- logger.Info("kvstore-perform-liveness-check-on-timeout")
-
- // Trigger Liveness check if no liveness update received within the timeout period.
- // The Liveness check will push Live state to same channel which this routine is
- // reading and processing. This, do it asynchronously to avoid blocking for
- // backend response and avoid any possibility of deadlock
- go core.backend.PerformLivenessCheck(ctx)
- }
- }
-}