add jmxfetch telemetry in code

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

@@ -28,6 +28,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.ListIterator;
@@ -897,6 +898,17 @@ public void init(final boolean forceNewConnection) {
             }
         }
 
+        if (appConfig.getInstanceTelemetry()) {
+            // If we have at least one check add jmxfetch_telemetry check
+            if (newInstances.size() >= 1) {
+                log.info("Adding jmxfetch instance telemetry check");
+                final Instance instance = instantiate(getInstanceTelemetryInstanceConfig(),
+                         getInstanceTelemetryInitConfig(), "jmxfetch_telemetry_check",
+                         this.appConfig);
+                newInstances.add(instance);
+            }
+        }
+
         final List<InstanceTask<Void>> instanceInitTasks =
                 new ArrayList<>(newInstances.size());
         for (Instance instance : newInstances) {
@@ -945,6 +957,34 @@ public TaskStatusHandler invoke(
         }
     }
 
+    private Map<String,Object> getInstanceTelemetryInitConfig() {
+        Map<String,Object> config = new HashMap<String,Object>();
+        config.put("is_jmx",true);
+        return config;
+    }
+
+    private Map<String,Object> getInstanceTelemetryInstanceConfig() {
+        Map<String,Object> config = new HashMap<String,Object>();
+        config.put("name","jmxfetch_telemetry_instance");
+        config.put("collect_default_jvm_metrics",true);
+        config.put("new_gc_metrics",true);
+        config.put("process_name_regex",".*org.datadog.jmxfetch.App.*");
+
+        List<Object> conf = new ArrayList<Object>();
+        Map<String,Object> confMap = new HashMap<String,Object>();
+        Map<String,Object> includeMap = new HashMap<String,Object>();
+        includeMap.put("domain","jmxfetch");
+        confMap.put("include", includeMap);
+        conf.add(confMap);
+        config.put("conf",conf);
+
+        List<String> tags = new ArrayList<String>();
+        tags.add("jmx:fetch");
+        config.put("tags", tags);
+
+        return config;
+    }
+
     static TaskStatusHandler processRecoveryResults(
             final Instance instance,
             final Future<Void> future,

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

@@ -122,6 +122,12 @@ public class AppConfig {
             required = false)
     private boolean statsdTelemetry;
 
+    @Parameter(
+            names = {"--instance_telemetry", "-it"},
+            description = "Enable jmxfetch instance telemetry reporting",
+            required = false)
+    private boolean instanceTelemetry;
+
     @Parameter(
             names = {"--statsd_queue_size", "-sq"},
             description = "Maximum number of unprocessed messages in the StatsD client queue.",
@@ -411,6 +417,10 @@ public boolean getStatsdTelemetry() {
         return statsdTelemetry;
     }
 
+    public boolean getInstanceTelemetry() {
+        return instanceTelemetry;
+    }
+
     public int getStatsdQueueSize() {
         return statsdQueueSize;
     }