list_jvms command

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

@@ -25,6 +25,7 @@
 import com.beust.jcommander.JCommander;
 import com.beust.jcommander.ParameterException;
 
+
 @SuppressWarnings("unchecked")
 public class App {
     private final static Logger LOGGER = Logger.getLogger(App.class.getName());
@@ -81,6 +82,16 @@ public static void main(String[] args) {
             System.exit(1);
         }
 
+        if(config.getAction().equals(AppConfig.ACTION_LIST_JVMS)) {
+            List<com.sun.tools.attach.VirtualMachineDescriptor> descriptors = com.sun.tools.attach.VirtualMachine.list();
+
+            System.out.println("List of JVMs for user " + System.getProperty("user.name") );
+            for(com.sun.tools.attach.VirtualMachineDescriptor descriptor : descriptors) {
+                System.out.println( "\tJVM id " + descriptor.id() + ": '" + descriptor.displayName() + "'" );
+            }
+            System.exit(0);
+        }
+
         // Set up the shutdown hook to properly close resources
         attachShutdownHook();
 
@@ -320,8 +331,10 @@ public void init(boolean forceNewConnection) {
         clearInstances(instances);
         clearInstances(brokenInstances);
 
+
         Reporter reporter = appConfig.getReporter();
 
+
         Iterator<Entry<String, YamlParser>> it = configs.entrySet().iterator();
         while (it.hasNext()) {
             Map.Entry<String, YamlParser> entry = it.next();
@@ -356,7 +369,7 @@ public void init(boolean forceNewConnection) {
                 } catch (IOException e) {
                     instance.cleanUp();
                     brokenInstances.add(instance);
-                    String warning = CANNOT_CONNECT_TO_INSTANCE + instance + " " + e.getMessage();
+                    String warning = CANNOT_CONNECT_TO_INSTANCE + instance + ". " + e.getMessage();
                     this.reportStatus(appConfig, reporter, instance, 0, warning, Status.STATUS_ERROR);
                     this.sendServiceCheck(reporter, instance, warning, Status.STATUS_ERROR);
                     LOGGER.error(warning);

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

@@ -18,14 +18,15 @@
 @Parameters(separators = "=")
 class AppConfig {
     public static final String ACTION_COLLECT = "collect";
+    public static final String ACTION_LIST_JVMS = "list_jvms";
     public static final String ACTION_LIST_EVERYTHING = "list_everything";
     public static final String ACTION_LIST_COLLECTED = "list_collected_attributes";
     public static final String ACTION_LIST_MATCHING = "list_matching_attributes";
     public static final String ACTION_LIST_NOT_MATCHING = "list_not_matching_attributes";
     public static final String ACTION_LIST_LIMITED = "list_limited_attributes";
     public static final String ACTION_HELP = "help";
     public static final HashSet<String> ACTIONS = new HashSet<String>(Arrays.asList(ACTION_COLLECT, ACTION_LIST_EVERYTHING,
-            ACTION_LIST_COLLECTED, ACTION_LIST_MATCHING, ACTION_LIST_NOT_MATCHING, ACTION_LIST_LIMITED, ACTION_HELP));
+            ACTION_LIST_COLLECTED, ACTION_LIST_MATCHING, ACTION_LIST_NOT_MATCHING, ACTION_LIST_LIMITED, ACTION_HELP, ACTION_LIST_JVMS));
 
     @Parameter(names = {"--help", "-h"},
             description = "Display this help page",
@@ -81,7 +82,7 @@ class AppConfig {
 
     @Parameter(description = "Action to take, should be in [help, collect, " +
             "list_everything, list_collected_attributes, list_matching_attributes, " +
-            "list_not_matching_attributes, list_limited_attributes]",
+            "list_not_matching_attributes, list_limited_attributes, list_jvms]",
             required = true)
     private List<String> action = null;
 

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

@@ -29,7 +29,7 @@ private JMXServiceURL getAddress(LinkedHashMap<String, Object> connectionParams)
             throw new IOException("Unnable to attach to process regex:  "+ processRegex, e);
         }
         return address;
-        
+
     }
 
      private String getJMXUrlForProcessRegex(String processRegex) throws com.sun.tools.attach.AttachNotSupportedException, IOException {
@@ -49,7 +49,8 @@ private String getJMXUrlForProcessRegex(String processRegex) throws com.sun.tool
                 return connectorAddress;
             }
         }
-        throw new IOException("Cannot find JVM matching regex: " + processRegex);
+
+        throw new IOException("No match found. Available JVMs can be listed with the `list_jvms` command.");
     }
 
     private void loadJMXAgent(com.sun.tools.attach.VirtualMachine vm) throws IOException {

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

@@ -136,7 +136,7 @@ public void init(boolean forceNewConnection) throws IOException, FailedLoginExce
     @Override
     public String toString() {
         if (this.yaml.get(PROCESS_NAME_REGEX) != null) {
-            return "process_regex: " + this.yaml.get(PROCESS_NAME_REGEX);
+            return "process_regex: `" + this.yaml.get(PROCESS_NAME_REGEX) + "`";
         } else if (this.yaml.get("jmx_url") != null) {
             return (String) this.yaml.get("jmx_url");
         } else {

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

@@ -312,7 +312,7 @@ public void testParsingAction() {
         } catch (ParameterException pe) {
             String expectedMessage = "Main parameters are required (\"Action to take, should be in [help, collect, " +
                     "list_everything, list_collected_attributes, list_matching_attributes, " +
-                    "list_not_matching_attributes, list_limited_attributes]\")";
+                    "list_not_matching_attributes, list_limited_attributes, list_jvms]\")";
             assertEquals(expectedMessage, pe.getMessage());
         }
 
@@ -329,7 +329,7 @@ public void testParsingAction() {
         } catch (ParameterException pe) {
             String expectedMessage = "Main parameters are required (\"Action to take, should be in [help, collect, " +
                     "list_everything, list_collected_attributes, list_matching_attributes, " +
-                    "list_not_matching_attributes, list_limited_attributes]\")";
+                    "list_not_matching_attributes, list_limited_attributes, list_jvms]\")";
             assertEquals(expectedMessage, pe.getMessage());
         }
     }

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

@@ -113,7 +113,7 @@ public void testServiceCheckCRITICAL() throws Exception {
 
         assertEquals(Reporter.formatServiceCheckPrefix("non_running_process"), scName);
         assertEquals(Status.STATUS_ERROR, scStatus);
-        assertEquals("Cannot connect to instance process_regex: .*non_running_process_test.* Cannot find JVM matching regex: .*non_running_process_test.*", scMessage);
+        assertEquals("Cannot connect to instance process_regex: `.*non_running_process_test.*`. No match found. Available JVMs can be listed with the `list_jvms` command.", scMessage);
         assertEquals(scTags.length, 3);
         assertTrue(Arrays.asList(scTags).contains("instance:jmx_test_instance"));
 
@@ -137,7 +137,7 @@ public void testServiceCheckCRITICAL() throws Exception {
 
         assertEquals(Reporter.formatServiceCheckPrefix("non_running_process"), scName);
         assertEquals(Status.STATUS_ERROR, scStatus);
-        assertEquals("Cannot connect to instance process_regex: .*non_running_process_test.*. Is a JMX Server running at this address?", scMessage);
+        assertEquals("Cannot connect to instance process_regex: `.*non_running_process_test.*`. Is a JMX Server running at this address?", scMessage);
         assertEquals(scTags.length, 3);
         assertTrue(Arrays.asList(scTags).contains("instance:jmx_test_instance"));
         assertTrue(Arrays.asList(scTags).contains("env:stage"));