Better support for running JMXFetch in the JVM.

More consistent file config with existing format.

src/main/java/org/datadog/jmxfetch/App.java

@@ -1,5 +1,7 @@
 package org.datadog.jmxfetch;
 
+import static org.datadog.jmxfetch.Instance.isDirectInstance;
+
 import com.google.common.primitives.Bytes;
 
 import com.beust.jcommander.JCommander;
@@ -827,8 +829,16 @@ public void init(boolean forceNewConnection) {
             }
 
             for (LinkedHashMap<String, Object> configInstance : configInstances) {
+                if (appConfig.isAllowDirectInstances() != isDirectInstance(configInstance)) {
+                    log.debug("Skipping instance '{}'. allowDirectInstances={} jvm_direct={}",
+                            name,
+                            appConfig.isAllowDirectInstances(),
+                            isDirectInstance(configInstance));
+                    continue;
+                }
+
                 // Create a new Instance object
-                log.info("Instantiating instance for: " + name);
+                log.info("Instantiating instance for: {}", name);
                 Instance instance =
                         instantiate(
                                 configInstance,

src/main/java/org/datadog/jmxfetch/AppConfig.java

@@ -204,6 +204,13 @@ public class AppConfig {
     @Builder.Default
     private int ipcPort = 0;
 
+    /**
+     * Boolean setting to determine whether to ignore jvm_direct instances.
+     * If set to true, other instances will be ignored.
+     */
+    @Builder.Default
+    private boolean allowDirectInstances = false;
+
     // This is used by things like APM agent to provide configuration from resources
     private List<String> instanceConfigResources;
     // This is used by things like APM agent to provide metric configuration from resources
@@ -339,6 +346,10 @@ public String getJmxLaunchFile() {
         return getTmpDirectory() + "/" + AD_LAUNCH_FILE;
     }
 
+    public boolean isAllowDirectInstances() {
+        return allowDirectInstances;
+    }
+
     public List<String> getInstanceConfigResources() {
         return instanceConfigResources;
     }

src/main/java/org/datadog/jmxfetch/ConnectionFactory.java

@@ -1,5 +1,7 @@
 package org.datadog.jmxfetch;
 
+import static org.datadog.jmxfetch.Instance.isDirectInstance;
+
 import lombok.extern.slf4j.Slf4j;
 
 import java.io.IOException;
@@ -9,11 +11,17 @@
 @Slf4j
 public class ConnectionFactory {
     public static final String PROCESS_NAME_REGEX = "process_name_regex";
-    private static ConnectionFactory connectionFactory = null;
 
     /** Factory method to create connections, both remote and local to the target JVM. */
     public static Connection createConnection(LinkedHashMap<String, Object> connectionParams)
             throws IOException {
+        // This is used by dd-java-agent to enable directly connecting to the mbean server.
+        // This works since jmxfetch is being run as a library inside the process being monitored.
+        if (isDirectInstance(connectionParams)) {
+            log.info("Connecting to JMX directly on the JVM");
+            return new JvmDirectConnection();
+        }
+
         if (connectionParams.get(PROCESS_NAME_REGEX) != null) {
             try {
                 Class.forName("com.sun.tools.attach.AttachNotSupportedException");
@@ -26,13 +34,6 @@ public static Connection createConnection(LinkedHashMap<String, Object> connecti
             return new AttachApiConnection(connectionParams);
         }
 
-        // This is used by dd-java-agent to enable directly connecting to the mbean server.
-        // This works because jmxfetch is being run as a library inside the process.
-        if ("service:jmx:local:///".equals(connectionParams.get("jmx_url"))) {
-            log.info("Connecting using JMX Local");
-            return new LocalConnection();
-        }
-
         log.info("Connecting using JMX Remote");
         return new RemoteConnection(connectionParams);
     }

src/main/java/org/datadog/jmxfetch/Instance.java

@@ -56,6 +56,7 @@ public class Instance {
     private static final int MAX_RETURNED_METRICS = 350;
     private static final int DEFAULT_REFRESH_BEANS_PERIOD = 600;
     public static final String PROCESS_NAME_REGEX = "process_name_regex";
+    public static final String JVM_DIRECT = "jvm_direct";
     public static final String ATTRIBUTE = "Attribute: ";
 
     private static final ThreadLocal<Yaml> YAML =
@@ -209,6 +210,11 @@ public Instance(
         loadDefaultConfig(gcMetricConfig);
     }
 
+    public static boolean isDirectInstance(LinkedHashMap<String, Object> configInstance) {
+        Object directInstance = configInstance.get(JVM_DIRECT);
+        return directInstance instanceof Boolean && (Boolean) directInstance;
+    }
+
     private void loadDefaultConfig(String configResourcePath) {
         ArrayList<LinkedHashMap<String, Object>> defaultConf =
                 (ArrayList<LinkedHashMap<String, Object>>)
@@ -221,8 +227,11 @@ private void loadDefaultConfig(String configResourcePath) {
     @VisibleForTesting
     static void loadMetricConfigFiles(
             AppConfig appConfig, LinkedList<Configuration> configurationList) {
-        if (appConfig.getMetricConfigFiles() != null) {
-            for (String fileName : appConfig.getMetricConfigFiles()) {
+        List<String> metricConfigFiles = appConfig.getMetricConfigFiles();
+        if (metricConfigFiles != null && !metricConfigFiles.isEmpty()) {
+            log.warn("Loading files via metricConfigFiles setting is deprecated.  Please "
+                    + "migrate to using standard agent config files in the conf.d directory.");
+            for (String fileName : metricConfigFiles) {
                 String yamlPath = new File(fileName).getAbsolutePath();
                 FileInputStream yamlInputStream = null;
                 log.info("Reading metric config file " + yamlPath);

src/main/java/org/datadog/jmxfetch/LocalConnection.java → src/main/java/org/datadog/jmxfetch/JvmDirectConnection.java

@@ -6,9 +6,9 @@
 import java.lang.management.ManagementFactory;
 
 @Slf4j
-public class LocalConnection extends Connection {
+public class JvmDirectConnection extends Connection {
 
-    public LocalConnection() throws IOException {
+    public JvmDirectConnection() throws IOException {
         createConnection();
     }
 

src/test/java/org/datadog/jmxfetch/TestApp.java

@@ -3,6 +3,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.when;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -490,6 +491,7 @@ public void testApp() throws Exception {
         registerMBean(testApp, "org.datadog.jmxfetch.test:type=SimpleTestJavaApp");
 
         // We do a first collection
+        when(appConfig.isAllowDirectInstances()).thenReturn(true);
         initApplication("jmx.yaml");
 
         run();

src/test/java/org/datadog/jmxfetch/TestServiceChecks.java

@@ -4,6 +4,7 @@
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.when;
 
 import java.util.Arrays;
 import java.util.HashMap;
@@ -19,6 +20,7 @@ public void testServiceCheckOK() throws Exception {
         registerMBean(new SimpleTestJavaApp(), "org.datadog.jmxfetch.test:type=ServiceCheckTest");
 
         // We do a first collection
+        when(appConfig.isAllowDirectInstances()).thenReturn(true);
         initApplication("jmx.yaml");
 
         run();
@@ -153,6 +155,7 @@ public void testServiceCheckCRITICAL() throws Exception {
 
     @Test
     public void testServiceCheckCounter() throws Exception {
+        when(appConfig.isAllowDirectInstances()).thenReturn(true);
         initApplication("jmx.yaml");
 
         Reporter repo = getReporter();

src/test/resources/jmx.yaml

@@ -1,7 +1,7 @@
 init_config:
 
 instances:
-    -   process_name_regex: .*surefire.*
+    -   jvm_direct: true
         refresh_beans: 4
         name: jmx_test_instance
         tags: