Add health check endpoints

README.md

@@ -124,6 +124,32 @@ The result of the above command is:
 }
 ```
 
+## Health check
+
+You can check the health status of the node.
+
+```bash
+$ ./bin/cete healthcheck | jq .
+```
+
+Also provides the following REST APIs
+
+### Liveness prove
+
+This endpoint always returns 200 and should be used to check Cete health.
+
+```bash
+$ curl -X GET http://localhost:8000/v1/liveness_check | jq .
+```
+
+### Readiness probe
+
+This endpoint returns 200 when Cete is ready to serve traffic (i.e. respond to queries).
+
+```bash
+$ curl -X GET http://localhost:8000/v1/readiness_check | jq .
+```
+
 ## Putting a key-value
 
 To put a key-value, execute the following command:

client/grpc_client.go

@@ -87,6 +87,22 @@ func (c *GRPCClient) Target() string {
 	return c.conn.Target()
 }
 
+func (c *GRPCClient) LivenessCheck(opts ...grpc.CallOption) (*protobuf.LivenessCheckResponse, error) {
+	if resp, err := c.client.LivenessCheck(c.ctx, &empty.Empty{}, opts...); err != nil {
+		return nil, err
+	} else {
+		return resp, nil
+	}
+}
+
+func (c *GRPCClient) ReadinessCheck(opts ...grpc.CallOption) (*protobuf.ReadinessCheckResponse, error) {
+	if resp, err := c.client.ReadinessCheck(c.ctx, &empty.Empty{}, opts...); err != nil {
+		return nil, err
+	} else {
+		return resp, nil
+	}
+}
+
 func (c *GRPCClient) Join(req *protobuf.JoinRequest, opts ...grpc.CallOption) error {
 	if _, err := c.client.Join(c.ctx, req, opts...); err != nil {
 		return err

cmd/healthcheck.go

@@ -0,0 +1,102 @@
+package cmd
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/mitchellh/go-homedir"
+	"github.com/mosuka/cete/client"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+var (
+	healthCheckCmd = &cobra.Command{
+		Use:   "healthcheck",
+		Short: "Health check a node",
+		Long:  "Health check a node",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			grpcAddress = viper.GetString("grpc_address")
+
+			certificateFile = viper.GetString("certificate_file")
+			commonName = viper.GetString("common_name")
+
+			c, err := client.NewGRPCClientWithContextTLS(grpcAddress, context.Background(), certificateFile, commonName)
+			if err != nil {
+				return err
+			}
+			defer func() {
+				_ = c.Close()
+			}()
+
+			lResp, err := c.LivenessCheck()
+			if err != nil {
+				return err
+			}
+
+			rResp, err := c.ReadinessCheck()
+			if err != nil {
+				return err
+			}
+
+			resp := map[string]bool{
+				"liveness":   lResp.Alive,
+				"readiness:": rResp.Ready,
+			}
+
+			respBytes, err := json.Marshal(resp)
+			if err != nil {
+				return err
+			}
+
+			fmt.Println(string(respBytes))
+
+			return nil
+		},
+	}
+)
+
+func init() {
+	rootCmd.AddCommand(healthCheckCmd)
+
+	cobra.OnInitialize(func() {
+		if configFile != "" {
+			viper.SetConfigFile(configFile)
+		} else {
+			home, err := homedir.Dir()
+			if err != nil {
+				_, _ = fmt.Fprintln(os.Stderr, err)
+				os.Exit(1)
+			}
+
+			viper.AddConfigPath("/etc")
+			viper.AddConfigPath(home)
+			viper.SetConfigName("cete")
+
+		}
+
+		viper.SetEnvPrefix("CETE")
+		viper.AutomaticEnv()
+
+		if err := viper.ReadInConfig(); err != nil {
+			switch err.(type) {
+			case viper.ConfigFileNotFoundError:
+				// cete.yaml does not found in config search path
+			default:
+				_, _ = fmt.Fprintln(os.Stderr, err)
+				os.Exit(1)
+			}
+		}
+	})
+
+	healthCheckCmd.PersistentFlags().StringVar(&configFile, "config-file", "", "config file. if omitted, cete.yaml in /etc and home directory will be searched")
+	healthCheckCmd.PersistentFlags().StringVar(&grpcAddress, "grpc-address", ":9000", "gRPC server listen address")
+	healthCheckCmd.PersistentFlags().StringVar(&certificateFile, "certificate-file", "", "path to the client server TLS certificate file")
+	healthCheckCmd.PersistentFlags().StringVar(&commonName, "common-name", "", "certificate common name")
+
+	_ = viper.BindPFlag("grpc_address", healthCheckCmd.PersistentFlags().Lookup("grpc-address"))
+	_ = viper.BindPFlag("certificate_file", healthCheckCmd.PersistentFlags().Lookup("certificate-file"))
+	_ = viper.BindPFlag("common_name", healthCheckCmd.PersistentFlags().Lookup("common-name"))
+}

errors/errors.go

@@ -1,24 +1,11 @@
-// Copyright (c) 2020 Minoru Osuka
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// 		http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
 package errors
 
 import "errors"
 
 var (
 	ErrNotFoundLeader    = errors.New("does not found leader")
 	ErrNodeAlreadyExists = errors.New("node already exists")
+	ErrNodeNotReady      = errors.New("node not ready")
 	ErrNotFound          = errors.New("not found")
 	ErrTimeout           = errors.New("timeout")
 )

marshaler/marshaler.go

@@ -1,17 +1,3 @@
-// Copyright (c) 2020 Minoru Osuka
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// 		http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
 package marshaler
 
 import (

marshaler/util.go

@@ -1,17 +1,3 @@
-// Copyright (c) 2020 Minoru Osuka
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// 		http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
 package marshaler
 
 import (
@@ -24,16 +10,25 @@ import (
 )
 
 func init() {
+	registry.RegisterType("protobuf.LivenessCheckResponse", reflect.TypeOf(protobuf.LivenessCheckResponse{}))
+	registry.RegisterType("protobuf.ReadinessCheckResponse", reflect.TypeOf(protobuf.ReadinessCheckResponse{}))
+	registry.RegisterType("protobuf.Metadata", reflect.TypeOf(protobuf.Metadata{}))
+	registry.RegisterType("protobuf.Node", reflect.TypeOf(protobuf.Node{}))
+	registry.RegisterType("protobuf.Cluster", reflect.TypeOf(protobuf.Cluster{}))
 	registry.RegisterType("protobuf.JoinRequest", reflect.TypeOf(protobuf.JoinRequest{}))
 	registry.RegisterType("protobuf.LeaveRequest", reflect.TypeOf(protobuf.LeaveRequest{}))
+	registry.RegisterType("protobuf.NodeResponse", reflect.TypeOf(protobuf.NodeResponse{}))
+	registry.RegisterType("protobuf.ClusterResponse", reflect.TypeOf(protobuf.ClusterResponse{}))
 	registry.RegisterType("protobuf.GetRequest", reflect.TypeOf(protobuf.GetRequest{}))
+	registry.RegisterType("protobuf.GetResponse", reflect.TypeOf(protobuf.GetResponse{}))
 	registry.RegisterType("protobuf.SetRequest", reflect.TypeOf(protobuf.SetRequest{}))
 	registry.RegisterType("protobuf.DeleteRequest", reflect.TypeOf(protobuf.DeleteRequest{}))
-	registry.RegisterType("protobuf.KeyValuePair", reflect.TypeOf(protobuf.KeyValuePair{}))
 	registry.RegisterType("protobuf.SetMetadataRequest", reflect.TypeOf(protobuf.SetMetadataRequest{}))
 	registry.RegisterType("protobuf.DeleteMetadataRequest", reflect.TypeOf(protobuf.DeleteMetadataRequest{}))
-	registry.RegisterType("protobuf.Metadata", reflect.TypeOf(protobuf.Metadata{}))
-	registry.RegisterType("protobuf.Node", reflect.TypeOf(protobuf.Node{}))
+	registry.RegisterType("protobuf.Event", reflect.TypeOf(protobuf.Event{}))
+	registry.RegisterType("protobuf.WatchResponse", reflect.TypeOf(protobuf.WatchResponse{}))
+	registry.RegisterType("protobuf.MetricsResponse", reflect.TypeOf(protobuf.MetricsResponse{}))
+	registry.RegisterType("protobuf.KeyValuePair", reflect.TypeOf(protobuf.KeyValuePair{}))
 	registry.RegisterType("map[string]interface {}", reflect.TypeOf((map[string]interface{})(nil)))
 }