HTTP client load balancing example

core-examples/README.adoc

@@ -66,6 +66,13 @@ And a simple HTTP client which makes a request to the server.
 
 link:src/main/java/io/vertx/example/core/http/simple/Client.java[Java simple HTTP client]
 
+=== Load balancing
+
+Demonstrate how to use client side load balancing
+
+link:src/main/java/io/vertx/example/core/http/loadbalancing/Servers.java[Start 3 HTTP servers on port 8080/8081/8082]
+link:src/main/java/io/vertx/example/core/http/loadbalancing/Client.java[HTTP client load balancing example]
+
 === HTTPS
 
 Like the simple example, but using HTTPS instead of HTTP

core-examples/src/main/java/io/vertx/example/core/http/loadbalancing/Client.java

@@ -0,0 +1,63 @@
+package io.vertx.example.core.http.loadbalancing;
+
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
+import io.vertx.core.http.HttpClient;
+import io.vertx.core.http.RequestOptions;
+import io.vertx.core.net.Address;
+import io.vertx.core.net.AddressResolver;
+import io.vertx.core.net.SocketAddress;
+import io.vertx.core.net.endpoint.LoadBalancer;
+import io.vertx.launcher.application.VertxApplication;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * @author <a href="mailto:[email protected]">Julien Viet</a>
+ */
+public class Client extends VerticleBase {
+
+  // This resolver simply response localhost:808x on a service.com:80 access
+  // we use such resolver here instead of DNS load balancing because there is no way to provide a local example
+  // with DNS load balancing that requires multiple network interfaces
+  private static final AddressResolver resolver = AddressResolver.mappingResolver(Collections
+    .<Address, List<SocketAddress>>singletonMap(SocketAddress.inetSocketAddress(80, "service.com"),
+      Arrays.asList(
+        SocketAddress.inetSocketAddress(8080, "localhost"),
+        SocketAddress.inetSocketAddress(8081, "localhost"),
+        SocketAddress.inetSocketAddress(8082, "localhost")))::get);
+
+  public static void main(String[] args) {
+    VertxApplication.main(new String[]{Client.class.getName()});
+  }
+
+  private HttpClient client;
+
+  @Override
+  public Future<?> start() throws Exception {
+
+    // Load balancer of your choice
+    LoadBalancer loadBalancer = LoadBalancer.RANDOM;
+
+    client = vertx.httpClientBuilder()
+      // In reality, we could avoid using such mock resolver and the client instead could use a server list provided by a DNS server
+      .withAddressResolver(resolver)
+      .withLoadBalancer(loadBalancer)
+      .build();
+
+    return client
+      .request(new RequestOptions().setServer(SocketAddress.inetSocketAddress(80, "service.com")))
+      .compose(request -> {
+        System.out.println("Interacting with server " + request.connection().remoteAddress());
+        return request
+          .send()
+          .compose(resp -> {
+            System.out.println("Got response " + resp.statusCode());
+            return resp.body();
+          });
+      })
+      .onSuccess(body -> System.out.println("Got data " + body.toString("ISO-8859-1")));
+  }
+}

core-examples/src/main/java/io/vertx/example/core/http/loadbalancing/Servers.java

@@ -0,0 +1,15 @@
+package io.vertx.example.core.http.loadbalancing;
+
+import io.vertx.core.Vertx;
+import io.vertx.example.core.http.simple.Server;
+
+public class Servers {
+
+  public static void main(String[] args) {
+    Vertx vertx = Vertx.vertx();
+    vertx.deployVerticle(new Server(8080)).await();
+    vertx.deployVerticle(new Server(8081)).await();
+    vertx.deployVerticle(new Server(8082)).await();
+    System.out.println("Servers listening on ports 8080/8081/8082");
+  }
+}

core-examples/src/main/java/io/vertx/example/core/http/simple/Server.java

@@ -13,13 +13,23 @@ public static void main(String[] args) {
     VertxApplication.main(new String[]{Server.class.getName()});
   }
 
+  private final int port;
+
+  public Server(int port) {
+    this.port = port;
+  }
+
+  public Server() {
+    this(8080);
+  }
+
   @Override
   public Future<?> start() throws Exception {
     return vertx
       .createHttpServer()
       .requestHandler(req -> {
         req.response().putHeader("content-type", "text/html").end("<html><body><h1>Hello from vert.x!</h1></body></html>");
       })
-      .listen(8080);
+      .listen(port);
   }
 }

grpc-examples/README.adoc

@@ -111,12 +111,12 @@ link:src/main/java/io/vertx/example/grpc/jsonformat/ServerWithStub.java[gRPC ser
 link:src/main/java/io/vertx/example/grpc/jsonformat/Client.java[gRPC client example]
 link:src/main/java/io/vertx/example/grpc/jsonformat/ClientWithStub.java[gRPC client stub example]
 
-== Load balancer
+== Load balancing
 
 Demonstrate how to use client side load balancing
 
-link:src/main/java/io/vertx/example/grpc/loadbalancer/Servers.java[Start 3 gRPC servers on port 8080/8081/8082]
-link:src/main/java/io/vertx/example/grpc/loadbalancer/Client.java[gRPC load balancing example]
+link:src/main/java/io/vertx/example/grpc/loadbalancing/Servers.java[Start 3 gRPC servers on port 8080/8081/8082]
+link:src/main/java/io/vertx/example/grpc/loadbalancing/Client.java[gRPC client load balancing example]
 
 == SSL example
 

grpc-examples/src/main/java/io/vertx/example/grpc/loadbalancer/Client.java → grpc-examples/src/main/java/io/vertx/example/grpc/loadbalancing/Client.java

@@ -1,4 +1,4 @@
-package io.vertx.example.grpc.loadbalancer;
+package io.vertx.example.grpc.loadbalancing;
 
 import io.grpc.examples.helloworld.HelloRequest;
 import io.grpc.examples.helloworld.VertxGreeterGrpcClient;
@@ -45,7 +45,7 @@ public Future<?> start() throws Exception {
 
     client = GrpcClient
       .builder(vertx)
-      // In reality we could avoid using such mock resolver and the client instead could use a server list provided by a DNS server
+      // In reality, we could avoid using such mock resolver and the client instead could use a server list provided by a DNS server
       .withAddressResolver(resolver)
       .withLoadBalancer(loadBalancer)
       .build();

grpc-examples/src/main/java/io/vertx/example/grpc/loadbalancer/Servers.java → grpc-examples/src/main/java/io/vertx/example/grpc/loadbalancing/Servers.java

@@ -1,4 +1,4 @@
-package io.vertx.example.grpc.loadbalancer;
+package io.vertx.example.grpc.loadbalancing;
 
 import io.vertx.core.Vertx;
 import io.vertx.example.grpc.helloworld.Server;
@@ -10,6 +10,6 @@ public static void main(String[] args) {
     vertx.deployVerticle(new Server(8080)).await();
     vertx.deployVerticle(new Server(8081)).await();
     vertx.deployVerticle(new Server(8082)).await();
-    System.out.println("Servers started on port 8080/8081/8082");
+    System.out.println("Servers listening on ports 8080/8081/8082");
   }
 }