feat: health check in RouteClient

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

@@ -53,7 +53,7 @@
 /**
  * The GreptimeDB client.
  */
-public class GreptimeDB implements Write, WriteObject, Lifecycle<GreptimeOptions>, HealthCheck, Display {
+public class GreptimeDB implements Write, WriteObject, Lifecycle<GreptimeOptions>, HealthChecker, Display {
 
     private static final Logger LOG = LoggerFactory.getLogger(GreptimeDB.class);
 
@@ -178,7 +178,7 @@ public StreamWriter<Table, WriteOk> streamWriter(int maxPointsPerSecond, Context
     }
 
     @Override
-    public CompletableFuture<Boolean> is_alive() {
+    public CompletableFuture<Map<Endpoint, Boolean>> checkHealth() {
         return null;
     }
 

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

@@ -16,6 +16,9 @@
 
 package io.greptime;
 
+import io.greptime.common.Endpoint;
+
+import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 
 /**
@@ -24,6 +27,6 @@
  *
  * @author jiachun.fjc
  */
-public interface HealthCheck {
-    CompletableFuture<Boolean> is_alive();
+public interface HealthChecker {
+    CompletableFuture<Map<Endpoint, Boolean>> checkHealth();
 }

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

@@ -33,17 +33,10 @@ public interface Router<R, E> {
     CompletableFuture<E> routeFor(R request);
 
     /**
-     * Refresh the routing table from remote server.
-     * @return a future that will be completed when the refresh is done
-     */
-    CompletableFuture<Boolean> refresh();
-
-    /**
-     * Refresh the routing table.
-     * We need to get all the endpoints, and this method will overwrite all
-     * current endpoints.
+     * Refresh the routing table. By health checker or service discovery.
      *
-     * @param endpoints all new endpoints
+     * @param activities all activities endpoints
+     * @param inactivities all inactivities endpoints
      */
-    void onRefresh(List<E> endpoints);
+    void onRefresh(List<E> activities, List<E> inactivities);
 }

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

@@ -25,20 +25,27 @@
 import io.greptime.rpc.Context;
 import io.greptime.rpc.Observer;
 import io.greptime.rpc.RpcClient;
+
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import io.greptime.v1.Health;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
  * A route rpc client which cached the routing table information locally
  * and will auto refresh.
  */
-public class RouterClient implements Lifecycle<RouterOptions>, Display {
+public class RouterClient implements Lifecycle<RouterOptions>, HealthChecker, Display {
 
     private static final Logger LOG = LoggerFactory.getLogger(RouterClient.class);
 
@@ -57,19 +64,29 @@ public boolean init(RouterOptions opts) {
         List<Endpoint> endpoints = Ensures.ensureNonNull(this.opts.getEndpoints(), "null `endpoints`");
 
         this.router = new DefaultRouter();
-        this.router.onRefresh(endpoints);
+        this.router.onRefresh(endpoints, null);
 
         long refreshPeriod = this.opts.getRefreshPeriodSeconds();
         if (refreshPeriod > 0) {
             this.refresher = REFRESHER_POOL.getObject();
             this.refresher.scheduleWithFixedDelay(
-                    () -> this.router.refresh().whenComplete((r, e) -> {
-                        if (e != null) {
-                            LOG.error("Router cache refresh failed.", e);
-                        } else {
-                            LOG.debug("Router cache refresh {}.", r ? "success" : "failed");
+                    () -> {
+                        try {
+                            Map<Endpoint, Boolean> health = this.checkHealth().get();
+                            List<Endpoint> activities = new ArrayList<>();
+                            List<Endpoint> inactivities = new ArrayList<>();
+                            for (Map.Entry<Endpoint, Boolean> entry : health.entrySet()) {
+                                if (entry.getValue()) {
+                                    activities.add(entry.getKey());
+                                } else {
+                                    inactivities.add(entry.getKey());
+                                }
+                            }
+                            this.router.onRefresh(activities, inactivities);
+                        } catch (Throwable t) {
+                            LOG.warn("Failed to check health", t);
                         }
-                    }),
+                    },
                     Util.randomInitialDelay(180),
                     refreshPeriod,
                     TimeUnit.SECONDS);
@@ -189,7 +206,9 @@ public <Req, Resp> Observer<Req> invokeClientStreaming(
 
     @Override
     public void display(Printer out) {
-        out.println("--- RouterClient ---").print("opts=").println(this.opts);
+        out.println("--- RouterClient ---")
+                .print("opts=")
+                .println(this.opts);
 
         if (this.rpcClient != null) {
             out.println("");
@@ -204,6 +223,25 @@ public String toString() {
         return "RouterClient{" + "refresher=" + refresher + ", opts=" + opts + ", rpcClient=" + rpcClient + '}';
     }
 
+    @Override
+    public CompletableFuture<Map<Endpoint, Boolean>> checkHealth() {
+        Map<Endpoint, CompletableFuture<Boolean>> futures = this.opts.getEndpoints()
+                .stream()
+                .collect(Collectors.toMap(Function.identity(), endpoint -> {
+                    Health.HealthCheckRequest req = Health.HealthCheckRequest.newBuilder().build();
+                    return this.invoke(endpoint, req, Context.newDefault())
+                            .thenApply(resp -> true)
+                            .exceptionally(t -> false); // Handle failure and return false
+                }));
+
+        return CompletableFuture.allOf(futures.values().toArray(new CompletableFuture[0]))
+                .thenApply(ok -> futures.entrySet().stream()
+                        .collect(Collectors.toMap(
+                                Map.Entry::getKey,
+                                e -> e.getValue().join()
+                        )));
+    }
+
     /**
      * Request to a `frontend` server, which needs to return all members(frontend server),
      * or it can return only one domain address, it is also possible to return no address
@@ -219,25 +257,46 @@ public String toString() {
      */
     private static class DefaultRouter implements Router<Void, Endpoint> {
 
-        private final AtomicReference<List<Endpoint>> endpointsRef = new AtomicReference<>();
+        private final AtomicReference<Endpoints> endpointsRef = new AtomicReference<>();
 
         @Override
         public CompletableFuture<Endpoint> routeFor(Void request) {
-            List<Endpoint> endpoints = this.endpointsRef.get();
+            Endpoints endpoints = this.endpointsRef.get();
+
+            if (endpoints == null) {
+                return Util.errorCf(new IllegalStateException("null `endpoints`"));
+            }
+
             ThreadLocalRandom random = ThreadLocalRandom.current();
-            int i = random.nextInt(0, endpoints.size());
-            return Util.completedCf(endpoints.get(i));
+
+            if (!endpoints.activities.isEmpty()) {
+                int i = random.nextInt(0, endpoints.activities.size());
+                return Util.completedCf(endpoints.activities.get(i));
+            }
+
+            if (!endpoints.inactivities.isEmpty()) {
+                int i = random.nextInt(0, endpoints.inactivities.size());
+                Endpoint goodLuck = endpoints.inactivities.get(i);
+                LOG.warn("No active endpoint, return an inactive one: {}", goodLuck);
+                return Util.completedCf(goodLuck);
+            }
+
+            return Util.errorCf(new IllegalStateException("empty `endpoints`"));
         }
 
         @Override
-        public CompletableFuture<Boolean> refresh() {
-            // always return true
-            return Util.completedCf(true);
+        public void onRefresh(List<Endpoint> activities, List<Endpoint> inactivities) {
+            this.endpointsRef.set(new Endpoints(activities, inactivities));
         }
+    }
 
-        @Override
-        public void onRefresh(List<Endpoint> endpoints) {
-            this.endpointsRef.set(endpoints);
+    static class Endpoints {
+        final List<Endpoint> activities;
+        final List<Endpoint> inactivities;
+
+        Endpoints(List<Endpoint> activities, List<Endpoint> inactivities) {
+            this.activities = activities == null ? new ArrayList<>() : activities;
+            this.inactivities = inactivities == null ? new ArrayList<>() : inactivities;
         }
     }
 }

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

@@ -31,19 +31,22 @@ public class RpcServiceRegister {
 
     public static void registerAllService() {
         // Handle
-        MethodDescriptor handleMethod = MethodDescriptor
-                .of(String.format(DATABASE_METHOD_TEMPLATE, "Handle"), MethodDescriptor.MethodType.UNARY, 1);
+        MethodDescriptor handleMethod = MethodDescriptor.of(
+                String.format(DATABASE_METHOD_TEMPLATE, "Handle"), MethodDescriptor.MethodType.UNARY, 1);
         RpcFactoryProvider.getRpcFactory()
-                .register(handleMethod,
+                .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);
+        MethodDescriptor handleRequestsMethod = MethodDescriptor.of(
+                String.format(DATABASE_METHOD_TEMPLATE, "HandleRequests"),
+                MethodDescriptor.MethodType.CLIENT_STREAMING);
         RpcFactoryProvider.getRpcFactory()
-                .register(handleRequestsMethod,
+                .register(
+                        handleRequestsMethod,
                         Database.GreptimeRequest.class,
                         Database.GreptimeRequest.getDefaultInstance(),
                         Database.GreptimeResponse.getDefaultInstance());
@@ -52,7 +55,8 @@ public static void registerAllService() {
         MethodDescriptor healthCheckMethod = MethodDescriptor.of(
                 String.format(HEALTH_METHOD_TEMPLATE, "HealthCheck"), MethodDescriptor.MethodType.UNARY);
         RpcFactoryProvider.getRpcFactory()
-                .register(healthCheckMethod,
+                .register(
+                        healthCheckMethod,
                         Health.HealthCheckRequest.class,
                         Health.HealthCheckRequest.getDefaultInstance(),
                         Health.HealthCheckResponse.getDefaultInstance());

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

@@ -138,6 +138,20 @@ public static <U> CompletableFuture<U> completedCf(U value) {
         return CompletableFuture.completedFuture(value);
     }
 
+    /**
+     * Returns a new CompletableFuture that is already exceptionally with the given
+     * error.
+     *
+     * @param t the given exception
+     * @param <U> the type of the value
+     * @return the exceptionally {@link CompletableFuture}
+     */
+    public static <U> CompletableFuture<U> errorCf(Throwable t) {
+        final CompletableFuture<U> err = new CompletableFuture<>();
+        err.completeExceptionally(t);
+        return err;
+    }
+
     public static <V> Observer<V> toObserver(CompletableFuture<V> future) {
         return new Observer<V>() {
 

ingester-protocol/src/test/java/io/greptime/options/GreptimeOptionsTest.java

@@ -88,19 +88,13 @@ public void testAllOptions() {
 
     private Router<Void, Endpoint> createTestRouter() {
         return new Router<Void, Endpoint>() {
-
             @Override
             public CompletableFuture<Endpoint> routeFor(Void request) {
                 return null;
             }
 
             @Override
-            public CompletableFuture<Boolean> refresh() {
-                return null;
-            }
-
-            @Override
-            public void onRefresh(List<Endpoint> endpoints) {}
+            public void onRefresh(List<Endpoint> activities, List<Endpoint> inactivities) {}
         };
     }
 }