Create a experimental HealthCheck GRPC Handler (#6225)

* Implementing HealthCheck grpc handlers

Signed-off-by: alanprot <alanprot@gmail.com>

* tests

Signed-off-by: alanprot <alanprot@gmail.com>

* lint

Signed-off-by: alanprot <alanprot@gmail.com>

* Adding tests

Signed-off-by: alanprot <alanprot@gmail.com>

* Name to the hc service + changelog

Signed-off-by: alanprot <alanprot@gmail.com>

---------

Signed-off-by: alanprot <alanprot@gmail.com>

Author: alanprot

CHANGELOG.md

@@ -17,6 +17,7 @@
 * [ENHANCEMENT] Distributor: Add new `cortex_reduced_resolution_histogram_samples_total` metric to track the number of histogram samples which resolution was reduced. #6182
 * [ENHANCEMENT] StoreGateway: Implement metadata API limit in queryable. #6195
 * [ENHANCEMENT] Ingester: Add matchers to ingester LabelNames() and LabelNamesStream() RPC. #6209
+* [ENHANCEMENT] Ingester/Store Gateway Clients: Introduce an experimental HealthCheck handler to quickly fail requests directed to unhealthy targets. #6225
 * [BUGFIX] Runtime-config: Handle absolute file paths when working directory is not / #6224
 
 ## 1.18.0 2024-09-03

docs/blocks-storage/querier.md

@@ -204,6 +204,24 @@ querier:
     # CLI flag: -querier.store-gateway-client.grpc-compression
     [grpc_compression: <string> | default = ""]
 
+    # EXPERIMENTAL: If enabled, gRPC clients perform health checks for each
+    # target and fail the request if the target is marked as unhealthy.
+    healthcheck_config:
+      # The number of consecutive failed health checks required before
+      # considering a target unhealthy. 0 means disabled.
+      # CLI flag: -querier.store-gateway-client.unhealthy-threshold
+      [unhealthy_threshold: <int> | default = 0]
+
+      # The approximate amount of time between health checks of an individual
+      # target.
+      # CLI flag: -querier.store-gateway-client.interval
+      [interval: <duration> | default = 5s]
+
+      # The amount of time during which no response from a target means a failed
+      # health check.
+      # CLI flag: -querier.store-gateway-client.timeout
+      [timeout: <duration> | default = 1s]
+
   # If enabled, store gateway query stats will be logged using `info` log level.
   # CLI flag: -querier.store-gateway-query-stats-enabled
   [store_gateway_query_stats: <boolean> | default = true]

docs/configuration/config-file-reference.md

@@ -3099,6 +3099,24 @@ grpc_client_config:
   # CLI flag: -ingester.client.tls-insecure-skip-verify
   [tls_insecure_skip_verify: <boolean> | default = false]
 
+  # EXPERIMENTAL: If enabled, gRPC clients perform health checks for each target
+  # and fail the request if the target is marked as unhealthy.
+  healthcheck_config:
+    # The number of consecutive failed health checks required before considering
+    # a target unhealthy. 0 means disabled.
+    # CLI flag: -ingester.client.unhealthy-threshold
+    [unhealthy_threshold: <int> | default = 0]
+
+    # The approximate amount of time between health checks of an individual
+    # target.
+    # CLI flag: -ingester.client.interval
+    [interval: <duration> | default = 5s]
+
+    # The amount of time during which no response from a target means a failed
+    # health check.
+    # CLI flag: -ingester.client.timeout
+    [timeout: <duration> | default = 1s]
+
 # Max inflight push requests that this ingester client can handle. This limit is
 # per-ingester-client. Additional requests will be rejected. 0 = unlimited.
 # CLI flag: -ingester.client.max-inflight-push-requests
@@ -3815,6 +3833,24 @@ store_gateway_client:
   # CLI flag: -querier.store-gateway-client.grpc-compression
   [grpc_compression: <string> | default = ""]
 
+  # EXPERIMENTAL: If enabled, gRPC clients perform health checks for each target
+  # and fail the request if the target is marked as unhealthy.
+  healthcheck_config:
+    # The number of consecutive failed health checks required before considering
+    # a target unhealthy. 0 means disabled.
+    # CLI flag: -querier.store-gateway-client.unhealthy-threshold
+    [unhealthy_threshold: <int> | default = 0]
+
+    # The approximate amount of time between health checks of an individual
+    # target.
+    # CLI flag: -querier.store-gateway-client.interval
+    [interval: <duration> | default = 5s]
+
+    # The amount of time during which no response from a target means a failed
+    # health check.
+    # CLI flag: -querier.store-gateway-client.timeout
+    [timeout: <duration> | default = 1s]
+
 # If enabled, store gateway query stats will be logged using `info` log level.
 # CLI flag: -querier.store-gateway-query-stats-enabled
 [store_gateway_query_stats: <boolean> | default = true]

pkg/cortex/modules.go

@@ -48,6 +48,7 @@ import (
 	"github.com/cortexproject/cortex/pkg/scheduler"
 	"github.com/cortexproject/cortex/pkg/storage/bucket"
 	"github.com/cortexproject/cortex/pkg/storegateway"
+	"github.com/cortexproject/cortex/pkg/util/grpcclient"
 	util_log "github.com/cortexproject/cortex/pkg/util/log"
 	"github.com/cortexproject/cortex/pkg/util/modules"
 	"github.com/cortexproject/cortex/pkg/util/runtimeconfig"
@@ -65,6 +66,7 @@ const (
 	Server                   string = "server"
 	Distributor              string = "distributor"
 	DistributorService       string = "distributor-service"
+	GrpcClientService        string = "grpcclient-service"
 	Ingester                 string = "ingester"
 	IngesterService          string = "ingester-service"
 	Flusher                  string = "flusher"
@@ -230,6 +232,19 @@ func (t *Cortex) initDistributorService() (serv services.Service, err error) {
 	return t.Distributor, nil
 }
 
+func (t *Cortex) initGrpcClientServices() (serv services.Service, err error) {
+	s := grpcclient.NewHealthCheckInterceptors(util_log.Logger)
+	if t.Cfg.IngesterClient.GRPCClientConfig.HealthCheckConfig.UnhealthyThreshold > 0 {
+		t.Cfg.IngesterClient.GRPCClientConfig.HealthCheckConfig.HealthCheckInterceptors = s
+	}
+
+	if t.Cfg.Querier.StoreGatewayClient.HealthCheckConfig.UnhealthyThreshold > 0 {
+		t.Cfg.Querier.StoreGatewayClient.HealthCheckConfig.HealthCheckInterceptors = s
+	}
+
+	return s, nil
+}
+
 func (t *Cortex) initDistributor() (serv services.Service, err error) {
 	t.API.RegisterDistributor(t.Distributor, t.Cfg.Distributor)
 
@@ -754,6 +769,7 @@ func (t *Cortex) setupModuleManager() error {
 	mm.RegisterModule(OverridesExporter, t.initOverridesExporter)
 	mm.RegisterModule(Distributor, t.initDistributor)
 	mm.RegisterModule(DistributorService, t.initDistributorService, modules.UserInvisibleModule)
+	mm.RegisterModule(GrpcClientService, t.initGrpcClientServices, modules.UserInvisibleModule)
 	mm.RegisterModule(Ingester, t.initIngester)
 	mm.RegisterModule(IngesterService, t.initIngesterService, modules.UserInvisibleModule)
 	mm.RegisterModule(Flusher, t.initFlusher)
@@ -782,14 +798,14 @@ func (t *Cortex) setupModuleManager() error {
 		Ring:                     {API, RuntimeConfig, MemberlistKV},
 		Overrides:                {RuntimeConfig},
 		OverridesExporter:        {RuntimeConfig},
-		Distributor:              {DistributorService, API},
+		Distributor:              {DistributorService, API, GrpcClientService},
 		DistributorService:       {Ring, Overrides},
 		Ingester:                 {IngesterService, Overrides, API},
 		IngesterService:          {Overrides, RuntimeConfig, MemberlistKV},
 		Flusher:                  {Overrides, API},
 		Queryable:                {Overrides, DistributorService, Overrides, Ring, API, StoreQueryable, MemberlistKV},
 		Querier:                  {TenantFederation},
-		StoreQueryable:           {Overrides, Overrides, MemberlistKV},
+		StoreQueryable:           {Overrides, Overrides, MemberlistKV, GrpcClientService},
 		QueryFrontendTripperware: {API, Overrides},
 		QueryFrontend:            {QueryFrontendTripperware},
 		QueryScheduler:           {API, Overrides},

pkg/ingester/client/client.go

@@ -111,8 +111,8 @@ func (c *closableHealthAndIngesterClient) Close() error {
 
 // Config is the configuration struct for the ingester client
 type Config struct {
-	GRPCClientConfig        grpcclient.Config `yaml:"grpc_client_config"`
-	MaxInflightPushRequests int64             `yaml:"max_inflight_push_requests"`
+	GRPCClientConfig        grpcclient.ConfigWithHealthCheck `yaml:"grpc_client_config"`
+	MaxInflightPushRequests int64                            `yaml:"max_inflight_push_requests"`
 }
 
 // RegisterFlags registers configuration settings used by the ingester client config.

pkg/querier/store_gateway_client.go

@@ -17,7 +17,7 @@ import (
 	"github.com/cortexproject/cortex/pkg/util/tls"
 )
 
-func newStoreGatewayClientFactory(clientCfg grpcclient.Config, reg prometheus.Registerer) client.PoolFactory {
+func newStoreGatewayClientFactory(clientCfg grpcclient.ConfigWithHealthCheck, reg prometheus.Registerer) client.PoolFactory {
 	requestDuration := promauto.With(reg).NewHistogramVec(prometheus.HistogramOpts{
 		Namespace:   "cortex",
 		Name:        "storegateway_client_request_duration_seconds",
@@ -31,7 +31,7 @@ func newStoreGatewayClientFactory(clientCfg grpcclient.Config, reg prometheus.Re
 	}
 }
 
-func dialStoreGatewayClient(clientCfg grpcclient.Config, addr string, requestDuration *prometheus.HistogramVec) (*storeGatewayClient, error) {
+func dialStoreGatewayClient(clientCfg grpcclient.ConfigWithHealthCheck, addr string, requestDuration *prometheus.HistogramVec) (*storeGatewayClient, error) {
 	opts, err := clientCfg.DialOption(grpcclient.Instrument(requestDuration))
 	if err != nil {
 		return nil, err
@@ -69,15 +69,18 @@ func (c *storeGatewayClient) RemoteAddress() string {
 
 func newStoreGatewayClientPool(discovery client.PoolServiceDiscovery, clientConfig ClientConfig, logger log.Logger, reg prometheus.Registerer) *client.Pool {
 	// We prefer sane defaults instead of exposing further config options.
-	clientCfg := grpcclient.Config{
-		MaxRecvMsgSize:      100 << 20,
-		MaxSendMsgSize:      16 << 20,
-		GRPCCompression:     clientConfig.GRPCCompression,
-		RateLimit:           0,
-		RateLimitBurst:      0,
-		BackoffOnRatelimits: false,
-		TLSEnabled:          clientConfig.TLSEnabled,
-		TLS:                 clientConfig.TLS,
+	clientCfg := grpcclient.ConfigWithHealthCheck{
+		Config: grpcclient.Config{
+			MaxRecvMsgSize:      100 << 20,
+			MaxSendMsgSize:      16 << 20,
+			GRPCCompression:     clientConfig.GRPCCompression,
+			RateLimit:           0,
+			RateLimitBurst:      0,
+			BackoffOnRatelimits: false,
+			TLSEnabled:          clientConfig.TLSEnabled,
+			TLS:                 clientConfig.TLS,
+		},
+		HealthCheckConfig: clientConfig.HealthCheckConfig,
 	}
 	poolCfg := client.PoolConfig{
 		CheckInterval:      time.Minute,
@@ -96,13 +99,15 @@ func newStoreGatewayClientPool(discovery client.PoolServiceDiscovery, clientConf
 }
 
 type ClientConfig struct {
-	TLSEnabled      bool             `yaml:"tls_enabled"`
-	TLS             tls.ClientConfig `yaml:",inline"`
-	GRPCCompression string           `yaml:"grpc_compression"`
+	TLSEnabled        bool                         `yaml:"tls_enabled"`
+	TLS               tls.ClientConfig             `yaml:",inline"`
+	GRPCCompression   string                       `yaml:"grpc_compression"`
+	HealthCheckConfig grpcclient.HealthCheckConfig `yaml:"healthcheck_config" doc:"description=EXPERIMENTAL: If enabled, gRPC clients perform health checks for each target and fail the request if the target is marked as unhealthy."`
 }
 
 func (cfg *ClientConfig) RegisterFlagsWithPrefix(prefix string, f *flag.FlagSet) {
 	f.BoolVar(&cfg.TLSEnabled, prefix+".tls-enabled", cfg.TLSEnabled, "Enable TLS for gRPC client connecting to store-gateway.")
 	f.StringVar(&cfg.GRPCCompression, prefix+".grpc-compression", "", "Use compression when sending messages. Supported values are: 'gzip', 'snappy' and '' (disable compression)")
 	cfg.TLS.RegisterFlagsWithPrefix(prefix, f)
+	cfg.HealthCheckConfig.RegisterFlagsWithPrefix(prefix, f)
 }

pkg/querier/store_gateway_client_test.go

@@ -36,7 +36,7 @@ func Test_newStoreGatewayClientFactory(t *testing.T) {
 
 	// Create a client factory and query back the mocked service
 	// with different clients.
-	cfg := grpcclient.Config{}
+	cfg := grpcclient.ConfigWithHealthCheck{}
 	flagext.DefaultValues(&cfg)
 
 	reg := prometheus.NewPedanticRegistry()

pkg/util/grpcclient/grpcclient.go

@@ -34,11 +34,21 @@ type Config struct {
 	SignWriteRequestsEnabled bool             `yaml:"-"`
 }
 
+type ConfigWithHealthCheck struct {
+	Config            `yaml:",inline"`
+	HealthCheckConfig HealthCheckConfig `yaml:"healthcheck_config" doc:"description=EXPERIMENTAL: If enabled, gRPC clients perform health checks for each target and fail the request if the target is marked as unhealthy."`
+}
+
 // RegisterFlags registers flags.
 func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
 	cfg.RegisterFlagsWithPrefix("", "", f)
 }
 
+func (cfg *ConfigWithHealthCheck) RegisterFlagsWithPrefix(prefix, defaultGrpcCompression string, f *flag.FlagSet) {
+	cfg.Config.RegisterFlagsWithPrefix(prefix, defaultGrpcCompression, f)
+	cfg.HealthCheckConfig.RegisterFlagsWithPrefix(prefix, f)
+}
+
 // RegisterFlagsWithPrefix registers flags with prefix.
 func (cfg *Config) RegisterFlagsWithPrefix(prefix, defaultGrpcCompression string, f *flag.FlagSet) {
 	f.IntVar(&cfg.MaxRecvMsgSize, prefix+".grpc-max-recv-msg-size", 100<<20, "gRPC client max receive message size (bytes).")
@@ -75,6 +85,15 @@ func (cfg *Config) CallOptions() []grpc.CallOption {
 	return opts
 }
 
+func (cfg *ConfigWithHealthCheck) DialOption(unaryClientInterceptors []grpc.UnaryClientInterceptor, streamClientInterceptors []grpc.StreamClientInterceptor) ([]grpc.DialOption, error) {
+	if cfg.HealthCheckConfig.HealthCheckInterceptors != nil {
+		unaryClientInterceptors = append(unaryClientInterceptors, cfg.HealthCheckConfig.UnaryHealthCheckInterceptor(cfg))
+		streamClientInterceptors = append(streamClientInterceptors, cfg.HealthCheckConfig.StreamClientInterceptor(cfg))
+	}
+
+	return cfg.Config.DialOption(unaryClientInterceptors, streamClientInterceptors)
+}
+
 // DialOption returns the config as a grpc.DialOptions.
 func (cfg *Config) DialOption(unaryClientInterceptors []grpc.UnaryClientInterceptor, streamClientInterceptors []grpc.StreamClientInterceptor) ([]grpc.DialOption, error) {
 	var opts []grpc.DialOption