First pass at embedding existing jmx integrations

Using copy/paste from integrations-core.  Will depend on a new jmxfetch release with DataDog/jmxfetch#205 before this will work.

dd-java-agent/agent-jmxfetch/src/main/java/datadog/trace/agent/jmxfetch/JMXFetch.java

@@ -2,9 +2,16 @@
 
 import com.google.common.collect.ImmutableList;
 import datadog.trace.api.Config;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.io.IOUtils;
 import org.datadog.jmxfetch.App;
 import org.datadog.jmxfetch.AppConfig;
 
@@ -27,6 +34,7 @@ private static void run(final Config config) {
       return;
     }
 
+    final List<String> internalMetricsConfigs = getInternalMetricFiles();
     final List<String> metricsConfigs = config.getJmxFetchMetricsConfigs();
     final Integer checkPeriod = config.getJmxFetchCheckPeriod();
     final Integer refreshBeansPeriod = config.getJmxFetchRefreshBeansPeriod();
@@ -36,7 +44,8 @@ private static void run(final Config config) {
     final String logLevel = getLogLevel();
 
     log.error(
-        "JMXFetch config: {} {} {} {} {} {} {}",
+        "JMXFetch config: {} {} {} {} {} {} {} {}",
+        internalMetricsConfigs,
         metricsConfigs,
         checkPeriod,
         refreshBeansPeriod,
@@ -47,6 +56,7 @@ private static void run(final Config config) {
     final AppConfig appConfig =
         AppConfig.create(
             DEFAULT_CONFIGS,
+            internalMetricsConfigs,
             metricsConfigs,
             checkPeriod,
             refreshBeansPeriod,
@@ -95,6 +105,29 @@ private static String getReporter(final Config config) {
     return "statsd:" + host + ":" + config.getJmxFetchStatsdPort();
   }
 
+  private static List<String> getInternalMetricFiles() {
+    try {
+      final InputStream metricConfigsStream =
+          JMXFetch.class.getResourceAsStream("metricconfigs.txt");
+      if (metricConfigsStream == null) {
+        log.debug("metricconfigs not found. returning empty set");
+        return Collections.emptyList();
+      } else {
+        final String configs = IOUtils.toString(metricConfigsStream, StandardCharsets.UTF_8);
+        final String[] split = configs.split("\n");
+        final List<String> result = new ArrayList<>(split.length);
+        for (final String config : split) {
+          final URL resource = JMXFetch.class.getResource("metricconfigs/" + config);
+          result.add(resource.getPath().split("\\.jar!/")[1]);
+        }
+        return result;
+      }
+    } catch (final IOException e) {
+      log.debug("error reading metricconfigs. returning empty set", e);
+      return Collections.emptyList();
+    }
+  }
+
   private static String getLogLocation() {
     return System.getProperty("org.slf4j.simpleLogger.logFile", "System.err");
   }

dd-java-agent/agent-jmxfetch/src/main/resources/datadog/trace/agent/jmxfetch/metricconfigs.txt

@@ -0,0 +1,5 @@
+activemq.yaml
+cassandra.yaml
+kafka.yaml
+solr.yaml
+tomcat.yaml

dd-java-agent/agent-jmxfetch/src/main/resources/datadog/trace/agent/jmxfetch/metricconfigs/activemq.yaml

@@ -0,0 +1,54 @@
+# Default metrics collected by this check. You should not have to modify this.
+jmx_metrics:
+- include:
+    destinationType: Queue
+    attribute:
+      AverageEnqueueTime:
+        alias: activemq.queue.avg_enqueue_time
+        metric_type: gauge
+      ConsumerCount:
+        alias: activemq.queue.consumer_count
+        metric_type: gauge
+      ProducerCount:
+        alias: activemq.queue.producer_count
+        metric_type: gauge
+      MaxEnqueueTime:
+        alias: activemq.queue.max_enqueue_time
+        metric_type: gauge
+      MinEnqueueTime:
+        alias: activemq.queue.min_enqueue_time
+        metric_type: gauge
+      MemoryPercentUsage:
+        alias: activemq.queue.memory_pct
+        metric_type: gauge
+      QueueSize:
+        alias: activemq.queue.size
+        metric_type: gauge
+      DequeueCount:
+        alias: activemq.queue.dequeue_count
+        metric_type: counter
+      DispatchCount:
+        alias: activemq.queue.dispatch_count
+        metric_type: counter
+      EnqueueCount:
+        alias: activemq.queue.enqueue_count
+        metric_type: counter
+      ExpiredCount:
+        alias: activemq.queue.expired_count
+        metric_type: counter
+      InFlightCount:
+        alias: activemq.queue.in_flight_count
+        metric_type: counter
+
+- include:
+    type: Broker
+    attribute:
+      StorePercentUsage:
+        alias: activemq.broker.store_pct
+        metric_type: gauge
+      TempPercentUsage:
+        alias: activemq.broker.temp_pct
+        metric_type: gauge
+      MemoryPercentUsage:
+        alias: activemq.broker.memory_pct
+        metric_type: gauge