feat: health check

ingester-protocol/src/main/java/io/greptime/GreptimeDB.java

@@ -53,7 +53,7 @@
 /**
  * The GreptimeDB client.
  */
-public class GreptimeDB implements Write, WriteObject, Lifecycle<GreptimeOptions>, Display {
+public class GreptimeDB implements Write, WriteObject, Lifecycle<GreptimeOptions>, HealthCheck, Display {
 
     private static final Logger LOG = LoggerFactory.getLogger(GreptimeDB.class);
 
@@ -177,6 +177,11 @@ public StreamWriter<Table, WriteOk> streamWriter(int maxPointsPerSecond, Context
         return this.writeClient.streamWriter(maxPointsPerSecond, attachCtx(ctx));
     }
 
+    @Override
+    public CompletableFuture<Boolean> is_alive() {
+        return null;
+    }
+
     @Override
     public void display(Printer out) {
         out.println("--- GreptimeDB Client ---")

ingester-protocol/src/main/java/io/greptime/HealthCheck.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2023 Greptime Team
+ *
+ * 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 io.greptime;
+
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Health check. It just like to probe the database and connections.
+ * Users can use this status to perform fault tolerance and disaster recovery actions.
+ *
+ * @author jiachun.fjc
+ */
+public interface HealthCheck {
+    CompletableFuture<Boolean> is_alive();
+}

ingester-protocol/src/main/java/io/greptime/RpcServiceRegister.java

@@ -19,31 +19,42 @@
 import io.greptime.rpc.MethodDescriptor;
 import io.greptime.rpc.RpcFactoryProvider;
 import io.greptime.v1.Database;
+import io.greptime.v1.Health;
 
 /**
  * The RPC service register.
  */
 public class RpcServiceRegister {
 
-    private static final String METHOD_TEMPLATE = "greptime.v1.GreptimeDatabase/%s";
+    private static final String DATABASE_METHOD_TEMPLATE = "greptime.v1.GreptimeDatabase/%s";
+    private static final String HEALTH_METHOD_TEMPLATE = "greptime.v1.Health/%s";
 
     public static void registerAllService() {
-        // register protobuf serializer
+        // Handle
+        MethodDescriptor handleMethod = MethodDescriptor
+                .of(String.format(DATABASE_METHOD_TEMPLATE, "Handle"), MethodDescriptor.MethodType.UNARY, 1);
         RpcFactoryProvider.getRpcFactory()
-                .register(
-                        MethodDescriptor.of(
-                                String.format(METHOD_TEMPLATE, "Handle"), MethodDescriptor.MethodType.UNARY, 1),
+                .register(handleMethod,
                         Database.GreptimeRequest.class,
                         Database.GreptimeRequest.getDefaultInstance(),
                         Database.GreptimeResponse.getDefaultInstance());
 
+        // HandleRequests
+        MethodDescriptor handleRequestsMethod = MethodDescriptor
+                .of(String.format(DATABASE_METHOD_TEMPLATE, "HandleRequests"), MethodDescriptor.MethodType.CLIENT_STREAMING);
         RpcFactoryProvider.getRpcFactory()
-                .register(
-                        MethodDescriptor.of(
-                                String.format(METHOD_TEMPLATE, "HandleRequests"),
-                                MethodDescriptor.MethodType.CLIENT_STREAMING),
+                .register(handleRequestsMethod,
                         Database.GreptimeRequest.class,
                         Database.GreptimeRequest.getDefaultInstance(),
                         Database.GreptimeResponse.getDefaultInstance());
+
+        // HealthCheck
+        MethodDescriptor healthCheckMethod = MethodDescriptor.of(
+                String.format(HEALTH_METHOD_TEMPLATE, "HealthCheck"), MethodDescriptor.MethodType.UNARY);
+        RpcFactoryProvider.getRpcFactory()
+                .register(healthCheckMethod,
+                        Health.HealthCheckRequest.class,
+                        Health.HealthCheckRequest.getDefaultInstance(),
+                        Health.HealthCheckResponse.getDefaultInstance());
     }
 }