Add Spring Boot xDS integration module boot4-xds

dependencies.toml

@@ -174,6 +174,8 @@ spring7 = "7.0.8"
 spring-boot2 = "2.7.18"
 spring-boot3 = "3.5.16"
 spring-boot4 = "4.1.0"
+spring-cloud-config-server = "5.0.4"
+spring-cloud-context = "5.0.2"
 testcontainers = "2.0.5"
 thrift09 = { strictly = "0.9.3-1" }
 thrift012 = { strictly = "0.12.0" }
@@ -1422,6 +1424,14 @@ version.ref = "spring-boot4"
 module = "org.springframework.boot:spring-boot-tomcat"
 version.ref = "spring-boot4"
 
+[libraries.spring-cloud-config-server]
+module = "org.springframework.cloud:spring-cloud-config-server"
+version.ref = "spring-cloud-config-server"
+
+[libraries.spring-cloud-context]
+module = "org.springframework.cloud:spring-cloud-context"
+version.ref = "spring-cloud-context"
+
 [libraries.testcontainers-core]
 module = "org.testcontainers:testcontainers"
 [libraries.testcontainers-consul]

examples/spring-cloud-config-xds/build.gradle

@@ -0,0 +1,15 @@
+dependencies {
+    implementation project(':spring:boot4-xds')
+    implementation libs.spring.cloud.config.server
+    testImplementation libs.spring.boot4.starter.test
+}
+
+tasks.register('runConfigServer', JavaExec) {
+    classpath = sourceSets.main.runtimeClasspath
+    mainClass = 'example.springframework.boot.xds.cloudconfig.server.ConfigServerMain'
+}
+
+tasks.register('runClient', JavaExec) {
+    classpath = sourceSets.main.runtimeClasspath
+    mainClass = 'example.springframework.boot.xds.cloudconfig.client.ClientMain'
+}

examples/spring-cloud-config-xds/src/main/java/example/springframework/boot/xds/cloudconfig/client/ClientMain.java

@@ -0,0 +1,49 @@
+package example.springframework.boot.xds.cloudconfig.client;
+
+import java.util.Map;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.linecorp.armeria.client.WebClient;
+import com.linecorp.armeria.common.AggregatedHttpResponse;
+
+/**
+ * A Spring Boot client application that loads xDS resources from a
+ * Spring Cloud Config Server. Properties are loaded from {@code application-client.yml}.
+ *
+ * <p>Exposes a {@code GET /relay?path=...} endpoint that forwards the request to
+ * the upstream resolved by the xDS listener and returns the response.
+ */
+@SpringBootApplication
+@RestController
+public class ClientMain {
+
+    private final WebClient xdsWebClient;
+
+    public ClientMain(WebClient xdsWebClient) {
+        this.xdsWebClient = xdsWebClient;
+    }
+
+    public static void main(String[] args) {
+        createApplication().run(args);
+    }
+
+    public static SpringApplication createApplication() {
+        final SpringApplication app = new SpringApplication(ClientMain.class);
+        app.setAdditionalProfiles("client");
+        // spring-cloud-config-server on the classpath disables the config client
+        // via ConfigServerBootstrapApplicationListener; re-enable it explicitly.
+        app.setDefaultProperties(Map.of("spring.cloud.config.enabled", "true"));
+        return app;
+    }
+
+    @GetMapping("/relay")
+    String relay(@RequestParam(defaultValue = "/actuator/health") String path) {
+        final AggregatedHttpResponse response = xdsWebClient.get(path).aggregate().join();
+        return response.status() + "\n" + response.contentUtf8();
+    }
+}

examples/spring-cloud-config-xds/src/main/java/example/springframework/boot/xds/cloudconfig/client/XdsClientConfig.java

@@ -0,0 +1,22 @@
+package example.springframework.boot.xds.cloudconfig.client;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import com.linecorp.armeria.client.WebClient;
+import com.linecorp.armeria.xds.XdsBootstrap;
+import com.linecorp.armeria.xds.client.endpoint.XdsHttpPreprocessor;
+
+@Configuration
+class XdsClientConfig {
+
+    @Bean
+    XdsHttpPreprocessor xdsHttpPreprocessor(XdsBootstrap xdsBootstrap) {
+        return XdsHttpPreprocessor.ofListener("test-listener", xdsBootstrap);
+    }
+
+    @Bean
+    WebClient xdsWebClient(XdsHttpPreprocessor xdsHttpPreprocessor) {
+        return WebClient.of(xdsHttpPreprocessor);
+    }
+}

examples/spring-cloud-config-xds/src/main/java/example/springframework/boot/xds/cloudconfig/server/ConfigServerMain.java

@@ -0,0 +1,26 @@
+package example.springframework.boot.xds.cloudconfig.server;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.config.server.EnableConfigServer;
+
+import com.linecorp.armeria.spring.xds.SpringXdsAutoConfiguration;
+
+/**
+ * A Spring Cloud Config Server that serves xDS cluster definitions from a native
+ * (file-based) repository.
+ */
+@EnableConfigServer
+@SpringBootApplication(exclude = SpringXdsAutoConfiguration.class)
+public class ConfigServerMain {
+
+    public static void main(String[] args) {
+        createApplication().run(args);
+    }
+
+    public static SpringApplication createApplication() {
+        final SpringApplication app = new SpringApplication(ConfigServerMain.class);
+        app.setAdditionalProfiles("server", "native");
+        return app;
+    }
+}

examples/spring-cloud-config-xds/src/main/resources/config-repo/application.yml

@@ -0,0 +1,37 @@
+armeria:
+  xds:
+    listener:
+      test-listener: |
+        name: test-listener
+        api_listener:
+          api_listener:
+            "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
+            codec_type: AUTO
+            stat_prefix: ingress_http
+            route_config:
+              name: local_route
+              virtual_hosts:
+                - name: local_service
+                  domains: ["*"]
+                  routes:
+                    - match:
+                        prefix: /
+                      route:
+                        cluster: test-cluster
+            http_filters:
+              - name: envoy.filters.http.router
+                typed_config:
+                  "@type": type.googleapis.com/envoy.extensions.filters.http.router.v3.Router
+    cluster:
+      test-cluster: |
+        name: test-cluster
+        type: STATIC
+        load_assignment:
+          cluster_name: test-cluster
+          endpoints:
+            - lb_endpoints:
+                - endpoint:
+                    address:
+                      socket_address:
+                        address: 127.0.0.1
+                        port_value: 8888

examples/spring-cloud-config-xds/src/main/resources/config/application-client.yml

@@ -0,0 +1,6 @@
+spring:
+  config:
+    "import": "configserver:"
+  cloud:
+    config:
+      uri: http://localhost:8888

examples/spring-cloud-config-xds/src/main/resources/config/application-server.yml

@@ -0,0 +1,9 @@
+server:
+  port: 8888
+
+spring:
+  cloud:
+    config:
+      server:
+        native:
+          searchLocations: classpath:/config-repo/

examples/spring-cloud-config-xds/src/test/java/example/springframework/boot/xds/cloudconfig/SpringCloudConfigXdsExampleTest.java

@@ -0,0 +1,128 @@
+package example.springframework.boot.xds.cloudconfig;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.awaitility.Awaitility.await;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.web.server.context.WebServerApplicationContext;
+import org.springframework.cloud.context.environment.EnvironmentChangeEvent;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
+
+import com.linecorp.armeria.client.WebClient;
+import com.linecorp.armeria.common.AggregatedHttpResponse;
+import com.linecorp.armeria.common.HttpStatus;
+import com.linecorp.armeria.xds.ClusterSnapshot;
+import com.linecorp.armeria.xds.XdsBootstrap;
+
+import example.springframework.boot.xds.cloudconfig.client.ClientMain;
+import example.springframework.boot.xds.cloudconfig.server.ConfigServerMain;
+
+@SpringBootTest(
+        classes = ClientMain.class,
+        properties = {
+                "spring.config.import=configserver:",
+                "spring.cloud.config.enabled=true"
+        })
+class SpringCloudConfigXdsExampleTest {
+
+    private static ConfigurableApplicationContext server;
+    private static int configPort;
+
+    @BeforeAll
+    static void startConfigServer() {
+        server = ConfigServerMain.createApplication().run("--server.port=0");
+
+        configPort = ((WebServerApplicationContext) server).getWebServer().getPort();
+        System.setProperty("spring.cloud.config.uri", "http://localhost:" + configPort);
+    }
+
+    @AfterAll
+    static void stopConfigServer() {
+        System.clearProperty("spring.cloud.config.uri");
+        if (server != null) {
+            server.close();
+        }
+    }
+
+    @Autowired
+    WebClient xdsWebClient;
+
+    @Autowired
+    XdsBootstrap xdsBootstrap;
+
+    @Autowired
+    ConfigurableEnvironment environment;
+
+    @Autowired
+    ApplicationContext applicationContext;
+
+    @Test
+    void webClientViaXdsPreprocessor() {
+        // Verify the initial cluster snapshot loaded from config server (port 8888)
+        final AtomicReference<ClusterSnapshot> snapshotRef = new AtomicReference<>();
+        xdsBootstrap.clusterRoot("test-cluster")
+                    .addSnapshotWatcher((snapshot, error) -> {
+                        if (snapshot != null) {
+                            snapshotRef.set(snapshot);
+                        }
+                    });
+        await().untilAsserted(() -> {
+            assertThat(snapshotRef.get()).isNotNull();
+            assertThat(endpointPort(snapshotRef.get())).isEqualTo(8888);
+        });
+
+        // Override the cluster endpoint to point at the config server's actual port
+        environment.getPropertySources()
+                   .addFirst(new MapPropertySource("test",
+                           Map.of("armeria.xds.cluster.test-cluster", clusterYaml(configPort))));
+        applicationContext.publishEvent(
+                new EnvironmentChangeEvent(Set.of("armeria.xds.cluster.test-cluster")));
+
+        // Wait for the xDS update to propagate
+        await().untilAsserted(() ->
+                assertThat(endpointPort(snapshotRef.get())).isEqualTo(configPort));
+
+        // Call the config server's actuator health endpoint via the xDS-resolved client
+        final AggregatedHttpResponse response =
+                xdsWebClient.get("/actuator/health").aggregate().join();
+        assertThat(response.status()).isEqualTo(HttpStatus.OK);
+    }
+
+    private static int endpointPort(ClusterSnapshot snapshot) {
+        return snapshot.xdsResource().resource()
+                       .getLoadAssignment()
+                       .getEndpoints(0)
+                       .getLbEndpoints(0)
+                       .getEndpoint()
+                       .getAddress()
+                       .getSocketAddress()
+                       .getPortValue();
+    }
+
+    private static String clusterYaml(int port) {
+        return """
+                name: test-cluster
+                type: STATIC
+                load_assignment:
+                  cluster_name: test-cluster
+                  endpoints:
+                    - lb_endpoints:
+                        - endpoint:
+                            address:
+                              socket_address:
+                                address: 127.0.0.1
+                                port_value: %d
+                """.formatted(port);
+    }
+}

settings.gradle

@@ -189,6 +189,7 @@ includeWithFlags ':spring:boot4-autoconfigure',          'java17', 'publish', 'r
 includeWithFlags ':spring:boot4-starter',                'java17', 'publish', 'relocate', 'no_aggregation'
 includeWithFlags ':spring:boot4-webflux-autoconfigure',  'java17', 'publish', 'relocate'
 includeWithFlags ':spring:boot4-webflux-starter',        'java17', 'publish', 'relocate', 'no_aggregation'
+includeWithFlags ':spring:boot4-xds',                    'java17', 'publish', 'relocate'
 includeWithFlags ':spring:spring7',                      'java17', 'publish', 'relocate'
 
 includeWithFlags ':dropwizard2',                         'java', 'publish', 'relocate'
@@ -332,6 +333,7 @@ includeWithFlags ':examples:spring-boot-minimal',                  'java17'
 includeWithFlags ':examples:spring-boot-minimal-kotlin',           'java17', 'kotlin'
 includeWithFlags ':examples:spring-boot-tomcat',                   'java17'
 includeWithFlags ':examples:spring-boot-webflux',                  'java17'
+includeWithFlags ':examples:spring-cloud-config-xds',              'java17'
 includeWithFlags ':examples:static-files',                         'java11'
 includeWithFlags ':examples:thrift',                               'java11'
 includeWithFlags ':examples:tutorials:grpc-tutorial',              'java11'

spring/boot4-xds/build.gradle

@@ -0,0 +1,9 @@
+dependencies {
+    api project(':xds')
+    api libs.spring.boot4.autoconfigure
+    api libs.spring.cloud.context
+
+    annotationProcessor libs.spring.boot4.configuration.processor
+
+    testImplementation libs.spring.boot4.starter.test
+}