Adding support for scenarios where the RMI registry has SSL enabled

jmx-metrics/README.md

@@ -22,14 +22,14 @@ otel.jmx.target.system = jvm,kafka
 otel.jmx.interval.milliseconds = 5000
 otel.jmx.username = my-username
 otel.jmx.password = my-password
-
+otel.jmx.remote.registry.ssl=false
 otel.metrics.exporter = otlp
 otel.exporter.otlp.endpoint = http://my-opentelemetry-collector:4317
 ```
 
 As configured in this example, the metric gatherer will establish an MBean server connection using the
 specified `otel.jmx.service.url` (required) and credentials and configure an OTLP gRPC metrics exporter reporting to
-`otel.exporter.otlp.endpoint`. After loading the included JVM and Kafka metric-gathering scripts determined by
+`otel.exporter.otlp.endpoint`. If SSL is enabled on the RMI registry for your server, the `otel.jmx.remote.registry.ssl` property must be set to `true`. After loading the included JVM and Kafka metric-gathering scripts determined by
 the comma-separated list in `otel.jmx.target.system`, it will then run the scripts on the desired interval
 length of `otel.jmx.interval.milliseconds` and export the resulting metrics.
 

jmx-metrics/src/main/groovy/io/opentelemetry/contrib/jmxmetrics/JmxClient.java

@@ -20,7 +20,6 @@
 import javax.management.MBeanServerConnection;
 import javax.management.ObjectName;
 import javax.management.remote.JMXConnector;
-import javax.management.remote.JMXConnectorFactory;
 import javax.management.remote.JMXServiceURL;
 
 public class JmxClient {
@@ -31,6 +30,7 @@ public class JmxClient {
   private final String password;
   private final String realm;
   private final String remoteProfile;
+  private final boolean registrySsl;
   @Nullable private JMXConnector jmxConn;
 
   JmxClient(final JmxConfig config) throws MalformedURLException {
@@ -39,6 +39,7 @@ public class JmxClient {
     this.password = config.password;
     this.realm = config.realm;
     this.remoteProfile = config.remoteProfile;
+    this.registrySsl = config.registrySsl;
   }
 
   public MBeanServerConnection getConnection() {
@@ -68,7 +69,7 @@ public MBeanServerConnection getConnection() {
         logger.warning("SASL unsupported in current environment: " + e.getMessage());
       }
 
-      jmxConn = JMXConnectorFactory.connect(url, env);
+      jmxConn = JmxConnectorHelper.connect(url, env, registrySsl);
       return jmxConn.getMBeanServerConnection();
     } catch (IOException e) {
       logger.log(Level.WARNING, "Could not connect to remote JMX server: ", e);

jmx-metrics/src/main/groovy/io/opentelemetry/contrib/jmxmetrics/JmxConfig.java

@@ -19,7 +19,7 @@ class JmxConfig {
   static final String INTERVAL_MILLISECONDS = PREFIX + "jmx.interval.milliseconds";
   static final String METRICS_EXPORTER_TYPE = PREFIX + "metrics.exporter";
   static final String EXPORTER = PREFIX + "exporter.";
-
+  static final String REGISTRY_SSL = PREFIX + "jmx.remote.registry.ssl";
   static final String EXPORTER_INTERVAL = PREFIX + "metric.export.interval";
 
   static final String OTLP_ENDPOINT = EXPORTER + "otlp.endpoint";
@@ -74,7 +74,7 @@ class JmxConfig {
   final String password;
   final String realm;
   final String remoteProfile;
-
+  final boolean registrySsl;
   final Properties properties;
 
   JmxConfig(final Properties props) {
@@ -111,6 +111,8 @@ class JmxConfig {
     remoteProfile = properties.getProperty(JMX_REMOTE_PROFILE);
     realm = properties.getProperty(JMX_REALM);
 
+    registrySsl = Boolean.valueOf(properties.getProperty(REGISTRY_SSL));
+
     // For the list of System Properties, if they have been set in the properties file
     // they need to be set in Java System Properties.
     JAVA_SYSTEM_PROPERTIES.forEach(

jmx-metrics/src/main/groovy/io/opentelemetry/contrib/jmxmetrics/JmxConnectorHelper.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.contrib.jmxmetrics;
+
+import java.io.IOException;
+import java.net.URI;
+import java.rmi.NotBoundException;
+import java.rmi.registry.LocateRegistry;
+import java.rmi.registry.Registry;
+import java.util.Map;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import javax.management.remote.JMXConnector;
+import javax.management.remote.JMXConnectorFactory;
+import javax.management.remote.JMXServiceURL;
+import javax.management.remote.rmi.RMIConnector;
+import javax.management.remote.rmi.RMIServer;
+import javax.rmi.ssl.SslRMIClientSocketFactory;
+
+public class JmxConnectorHelper {
+
+  private static final Logger logger = Logger.getLogger(JmxConnectorHelper.class.getName());
+
+  private static RMIServer stub = null;
+  private static final SslRMIClientSocketFactory sslRMIClientSocketFactory =
+      new SslRMIClientSocketFactory();
+
+  private JmxConnectorHelper() {}
+
+  /**
+   * To use SSL, the {@link RMIServer} stub used by the {@link RMIConnector} must be built
+   * separately. As a result, we have to unwind the {@link JMXConnectorFactory#connect} method and
+   * reimplement pieces.
+   */
+  public static JMXConnector connect(
+      JMXServiceURL serviceURL, Map<String, Object> env, boolean registrySsl) throws IOException {
+
+    // Different connection logic is needed when SSL is enabled on the RMI registry
+    if (!registrySsl) {
+      return JMXConnectorFactory.connect(serviceURL, env);
+    }
+
+    logger.log(Level.INFO, "Attempting to connect to an SSL-protected RMI registry");
+
+    String hostName;
+    int port;
+
+    if (serviceURL.getURLPath().startsWith("/jndi/")) {
+      final String[] components = serviceURL.getURLPath().split("/", 3);
+      final URI uri = URI.create(components[2]);
+      hostName = uri.getHost();
+      port = uri.getPort();
+    } else {
+      hostName = serviceURL.getHost();
+      port = serviceURL.getPort();
+    }
+
+    if (stub == null) {
+      stub = getStub(hostName, port);
+    }
+    JMXConnector jmxConn = new RMIConnector(stub, null);
+    jmxConn.connect(env);
+    return jmxConn;
+  }
+
+  private static RMIServer getStub(String hostName, int port) throws IOException {
+    try {
+      Registry registry = LocateRegistry.getRegistry(hostName, port, sslRMIClientSocketFactory);
+      return (RMIServer) registry.lookup("jmxrmi");
+    } catch (NotBoundException nbe) {
+      throw new IOException(nbe);
+    }
+  }
+}