Integration tests for JMX Scraper (#1480)

Co-authored-by: Sylvain Juge <763082+SylvainJuge@users.noreply.github.com>

jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/JmxConnectorBuilderTest.java

@@ -31,23 +31,25 @@ static void afterAll() {
 
   @Test
   void noAuth() {
-    try (TestAppContainer app = new TestAppContainer().withNetwork(network).withJmxPort(9990)) {
+    int port = PortSelector.getAvailableRandomPort();
+    try (TestAppContainer app = new TestAppContainer().withHostAccessFixedJmxPort(port)) {
       app.start();
       testConnector(
-          () -> JmxConnectorBuilder.createNew(app.getHost(), app.getMappedPort(9990)).build());
+          () -> JmxConnectorBuilder.createNew(app.getHost(), app.getMappedPort(port)).build());
     }
   }
 
   @Test
   void loginPwdAuth() {
+    int port = PortSelector.getAvailableRandomPort();
     String login = "user";
     String pwd = "t0p!Secret";
     try (TestAppContainer app =
-        new TestAppContainer().withNetwork(network).withJmxPort(9999).withUserAuth(login, pwd)) {
+        new TestAppContainer().withHostAccessFixedJmxPort(port).withUserAuth(login, pwd)) {
       app.start();
       testConnector(
           () ->
-              JmxConnectorBuilder.createNew(app.getHost(), app.getMappedPort(9999))
+              JmxConnectorBuilder.createNew(app.getHost(), app.getMappedPort(port))
                   .userCredentials(login, pwd)
                   .build());
     }

jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/PortSelector.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.contrib.jmxscraper;
+
+import java.io.IOException;
+import java.net.Socket;
+import java.util.Random;
+
+/** Class used for finding random free network port from range 1024-65535 */
+public class PortSelector {
+  private static final Random random = new Random(System.currentTimeMillis());
+
+  private static final int MIN_PORT = 1024;
+  private static final int MAX_PORT = 65535;
+
+  private PortSelector() {}
+
+  /**
+   * @return random available TCP port
+   */
+  public static synchronized int getAvailableRandomPort() {
+    int port;
+
+    do {
+      port = random.nextInt(MAX_PORT - MIN_PORT + 1) + MIN_PORT;
+    } while (!isPortAvailable(port));
+
+    return port;
+  }
+
+  private static boolean isPortAvailable(int port) {
+    // see https://stackoverflow.com/a/13826145 for the chosen implementation
+    try (Socket s = new Socket("localhost", port)) {
+      return false;
+    } catch (IOException e) {
+      return true;
+    }
+  }
+}

jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/TestAppContainer.java

@@ -25,7 +25,6 @@
 public class TestAppContainer extends GenericContainer<TestAppContainer> {
 
   private final Map<String, String> properties;
-  private int port;
   private String login;
   private String pwd;
 
@@ -44,11 +43,16 @@ public TestAppContainer() {
         .withCommand("java", "-jar", "/app.jar");
   }
 
+  /**
+   * Configures app container for container-to-container access
+   *
+   * @param port mapped port to use
+   * @return this
+   */
   @CanIgnoreReturnValue
   public TestAppContainer withJmxPort(int port) {
-    this.port = port;
     properties.put("com.sun.management.jmxremote.port", Integer.toString(port));
-    return this.withExposedPorts(port);
+    return this;
   }
 
   @CanIgnoreReturnValue
@@ -58,9 +62,30 @@ public TestAppContainer withUserAuth(String login, String pwd) {
     return this;
   }
 
+  /**
+   * Configures app container for host-to-container access, port will be used as-is from host to
+   * work-around JMX in docker. This is optional on Linux as there is a network route and the
+   * container is accessible, but not on Mac where the container runs in an isolated VM.
+   *
+   * @param port port to use, must be available on host.
+   * @return this
+   */
+  @CanIgnoreReturnValue
+  public TestAppContainer withHostAccessFixedJmxPort(int port) {
+    // To get host->container JMX connection working docker must expose JMX/RMI port under the same
+    // port number. Because of this testcontainers' standard exposed port randomization approach
+    // can't be used.
+    // Explanation:
+    // https://forums.docker.com/t/exposing-mapped-jmx-ports-from-multiple-containers/5287/6
+    properties.put("com.sun.management.jmxremote.port", Integer.toString(port));
+    properties.put("com.sun.management.jmxremote.rmi.port", Integer.toString(port));
+    properties.put("java.rmi.server.hostname", getHost());
+    addFixedExposedPort(port, port);
+    return this;
+  }
+
   @Override
   public void start() {
-
     // TODO: add support for ssl
     properties.put("com.sun.management.jmxremote.ssl", "false");
 
@@ -92,11 +117,9 @@ public void start() {
 
     this.withEnv("JAVA_TOOL_OPTIONS", confArgs);
 
-    logger().info("Test application JAVA_TOOL_OPTIONS = " + confArgs);
+    logger().info("Test application JAVA_TOOL_OPTIONS = {}", confArgs);
 
     super.start();
-
-    logger().info("Test application JMX port mapped to {}:{}", getHost(), getMappedPort(port));
   }
 
   private static Path createPwdFile(String login, String pwd) {

jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/target_systems/TargetSystemIntegrationTest.java

@@ -5,24 +5,19 @@
 
 package io.opentelemetry.contrib.jmxscraper.target_systems;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
 import com.linecorp.armeria.server.ServerBuilder;
 import com.linecorp.armeria.server.grpc.GrpcService;
 import com.linecorp.armeria.testing.junit5.server.ServerExtension;
 import io.grpc.stub.StreamObserver;
-import io.opentelemetry.contrib.jmxscraper.JmxConnectorBuilder;
 import io.opentelemetry.contrib.jmxscraper.JmxScraperContainer;
 import io.opentelemetry.proto.collector.metrics.v1.ExportMetricsServiceRequest;
 import io.opentelemetry.proto.collector.metrics.v1.ExportMetricsServiceResponse;
 import io.opentelemetry.proto.collector.metrics.v1.MetricsServiceGrpc;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.LinkedBlockingDeque;
-import javax.management.remote.JMXConnector;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeAll;
@@ -35,8 +30,8 @@
 import org.testcontainers.containers.output.Slf4jLogConsumer;
 
 public abstract class TargetSystemIntegrationTest {
-
-  private static final Logger logger = LoggerFactory.getLogger(TargetSystemIntegrationTest.class);
+  private static final Logger targetSystemLogger = LoggerFactory.getLogger("TargetSystemContainer");
+  private static final Logger jmxScraperLogger = LoggerFactory.getLogger("JmxScraperContainer");
   private static final String TARGET_SYSTEM_NETWORK_ALIAS = "targetsystem";
   private static String otlpEndpoint;
 
@@ -54,6 +49,9 @@ public abstract class TargetSystemIntegrationTest {
   private JmxScraperContainer scraper;
 
   private static final String OTLP_HOST = "host.testcontainers.internal";
+
+  // JMX communication only happens between container, and we don't have to use JMX
+  // from host to container, we can use a fixed port.
   private static final int JMX_PORT = 9999;
 
   @BeforeAll
@@ -93,27 +91,14 @@ void endToEndTest() {
 
     target =
         createTargetContainer(JMX_PORT)
-            .withLogConsumer(new Slf4jLogConsumer(logger))
+            .withLogConsumer(new Slf4jLogConsumer(targetSystemLogger))
             .withNetwork(network)
-            .withExposedPorts(JMX_PORT)
             .withNetworkAliases(TARGET_SYSTEM_NETWORK_ALIAS);
     target.start();
 
-    String targetHost = target.getHost();
-    Integer targetPort = target.getMappedPort(JMX_PORT);
-    logger.info(
-        "Target system started, JMX port: {} mapped to {}:{}", JMX_PORT, targetHost, targetPort);
-
-    // TODO : wait for metrics to be sent and add assertions on what is being captured
-    // for now we just test that we can connect to remote JMX using our client.
-    try (JMXConnector connector = JmxConnectorBuilder.createNew(targetHost, targetPort).build()) {
-      assertThat(connector.getMBeanServerConnection()).isNotNull();
-    } catch (IOException e) {
-      throw new RuntimeException(e);
-    }
-
     scraper =
         new JmxScraperContainer(otlpEndpoint)
+            .withLogConsumer(new Slf4jLogConsumer(jmxScraperLogger))
             .withNetwork(network)
             .withService(TARGET_SYSTEM_NETWORK_ALIAS, JMX_PORT);
 

jmx-scraper/src/main/java/io/opentelemetry/contrib/jmxscraper/JmxConnectorBuilder.java

@@ -138,6 +138,7 @@ private Map<String, Object> buildEnv() {
   @SuppressWarnings("BanJNDI")
   private static JMXConnector doConnect(JMXServiceURL url, Map<String, Object> env)
       throws IOException {
+    logger.info("Connecting to " + url);
     return JMXConnectorFactory.connect(url, env);
   }