cassandra_aliasing to comply with CASSANDRA-4009

Create a `cassandra_aliasing` flag to select the appropriate aliasing
logic.
* `cassandra_aliasing` → compliant with CASSANDRA-4009
* default behavior

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

@@ -44,6 +44,7 @@ public class Instance {
     private boolean limitReached;
     private Connection connection;
     private AppConfig appConfig;
+    private Boolean cassandraAliasing;
 
 
     public Instance(Instance instance, AppConfig appConfig) {
@@ -95,6 +96,13 @@ public Instance(LinkedHashMap<String, Object> yamlInstance, LinkedHashMap<String
             }
         }
 
+        // Alternative aliasing for CASSANDRA-4009 metrics
+        // More information: https://issues.apache.org/jira/browse/CASSANDRA-4009
+        this.cassandraAliasing = (Boolean) yaml.get("cassandra_aliasing");
+        if (this.cassandraAliasing == null){
+            this.cassandraAliasing = false;
+        }
+
         // In case the configuration to match beans is not specified in the "instance" parameter but in the initConfig one
         Object yamlConf = this.yaml.get("conf");
         if (yamlConf == null && this.initConfig != null) {
@@ -221,7 +229,7 @@ private void getMatchingAttributes() {
                 String attributeType = attributeInfo.getType();
                 if (SIMPLE_TYPES.contains(attributeType)) {
                     LOGGER.debug("Attribute: " + beanName + " : " + attributeInfo + " has attributeInfo simple type");
-                    jmxAttribute = new JMXSimpleAttribute(attributeInfo, beanName, instanceName, connection, tags);
+                    jmxAttribute = new JMXSimpleAttribute(attributeInfo, beanName, instanceName, connection, tags, cassandraAliasing);
                 } else if (COMPOSED_TYPES.contains(attributeType)) {
                     LOGGER.debug("Attribute: " + beanName + " : " + attributeInfo + " has attributeInfo complex type");
                     jmxAttribute = new JMXComplexAttribute(attributeInfo, beanName, instanceName, connection, tags);

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

@@ -42,25 +42,28 @@ public abstract class JMXAttribute {
     protected String[] tags;
     private Configuration matchingConf;
     private LinkedList<String> defaultTagsList;
+    private Boolean cassandraAliasing;
 
     JMXAttribute(MBeanAttributeInfo attribute, ObjectName beanName, String instanceName,
-            Connection connection, HashMap<String, String> instanceTags) {
+            Connection connection, HashMap<String, String> instanceTags, Boolean cassandraAliasing) {
         this.attribute = attribute;
         this.beanName = beanName;
         this.matchingConf = null;
         this.connection = connection;
         this.attributeName = attribute.getName();
         this.beanStringName = beanName.toString();
+        this.cassandraAliasing = cassandraAliasing;
 
         // A bean name is formatted like that: org.apache.cassandra.db:type=Caches,keyspace=system,cache=HintsColumnFamilyKeyCache
         // i.e. : domain:bean_parameter1,bean_parameter2
         String[] splitBeanName = beanStringName.split(":");
         String domain = splitBeanName[0];
         String beanParameters = splitBeanName[1];
+        this.domain = domain;
+
         HashMap<String, String> beanParametersHash = getBeanParametersHash(beanParameters);
-        LinkedList<String> beanParametersList = getBeanParametersList(instanceName, domain, beanParametersHash, instanceTags);
+        LinkedList<String> beanParametersList = getBeanParametersList(instanceName, beanParametersHash, instanceTags);
 
-        this.domain = domain;
         this.beanParameters = beanParametersHash;
         this.defaultTagsList = renameConflictingParameters(beanParametersList);
     }
@@ -80,12 +83,12 @@ public static HashMap<String, String> getBeanParametersHash(String beanParameter
         return beanParamsMap;
     }
 
-    private static LinkedList<String> getBeanParametersList(String instanceName, String domain, Map<String, String> beanParameters, HashMap<String, String> instanceTags) {
+    private LinkedList<String> getBeanParametersList(String instanceName, Map<String, String> beanParameters, HashMap<String, String> instanceTags) {
         LinkedList<String> beanTags = new LinkedList<String>();
         beanTags.add("instance:" + instanceName);
         beanTags.add("jmx_domain:" + domain);
 
-        if (domain.equals(CASSANDRA_DOMAIN)) {
+        if (renameCassandraMetrics()) {
             beanTags.addAll(getCassandraBeanTags(beanParameters));
         } else {
             for (Map.Entry<String, String> param : beanParameters.entrySet()) {
@@ -119,6 +122,10 @@ private static LinkedList<String> renameConflictingParameters(LinkedList<String>
         return defaultTagsList;
     }
 
+    protected Boolean renameCassandraMetrics(){
+        return cassandraAliasing && domain.equals(CASSANDRA_DOMAIN);
+    }
+
     private static Collection<String> getCassandraBeanTags(Map<String, String> beanParameters) {
         Collection<String> tags = new LinkedList<String>();
         for (Map.Entry<String, String> param : beanParameters.entrySet()) {

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

@@ -23,7 +23,7 @@ public class JMXComplexAttribute extends JMXAttribute {
 
     public JMXComplexAttribute(MBeanAttributeInfo attribute, ObjectName beanName, String instanceName,
                                Connection connection, HashMap<String, String> instanceTags) {
-        super(attribute, beanName, instanceName, connection, instanceTags);
+        super(attribute, beanName, instanceName, connection, instanceTags, false);
         this.subAttributeList = new HashMap<String, HashMap<String, Object>>();
     }
 

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

@@ -21,8 +21,8 @@ public class JMXSimpleAttribute extends JMXAttribute {
     private String metricType;
 
     public JMXSimpleAttribute(MBeanAttributeInfo attribute, ObjectName beanName, String instanceName,
-                              Connection connection, HashMap<String, String> instanceTags) {
-        super(attribute, beanName, instanceName, connection, instanceTags);
+                              Connection connection, HashMap<String, String> instanceTags, Boolean cassandraAliasing) {
+        super(attribute, beanName, instanceName, connection, instanceTags, cassandraAliasing);
     }
 
     @Override
@@ -105,7 +105,7 @@ private String getAlias() {
     }
 
     private String getCassandraAlias() {
-        if (getDomain().equals(CASSANDRA_DOMAIN)) {
+        if (renameCassandraMetrics()) {
             Map<String, String> beanParameters = getBeanParameters();
             String type = beanParameters.get("type");
             String metricName = beanParameters.get("name");

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

@@ -56,6 +56,12 @@ public void testBeanTags() throws Exception {
         }
     }
 
+    /**
+     * Check JMXFetch Cassandra metric aliasing logic, i.e. compliant with CASSANDRA-4009
+     * when `cassandra4009` flag is enabled, or default.
+     *
+     * More information: https://issues.apache.org/jira/browse/CASSANDRA-4009
+     */
     @Test
     public void testCassandraBean() throws Exception {
         // We expose a few metrics through JMX
@@ -67,18 +73,31 @@ public void testCassandraBean() throws Exception {
         run();
         LinkedList<HashMap<String, Object>> metrics = getMetrics();
 
-        // 14 = 13 metrics from java.lang + 1 metric explicitly defined in the yaml config file
-        assertEquals(14, metrics.size());
+        // 14 = 2*13 metrics from java.lang + 2*1 metric explicitly defined in the yaml config file
+        assertEquals(28, metrics.size());
 
+        // Assert compliancy with CASSANDRA-4009
         ArrayList<String> tags = new ArrayList<String>() {{
             add("type:ColumnFamily");
             add("keyspace:MyKeySpace");
             add("ColumnFamily:MyColumnFamily");
             add("jmx_domain:org.apache.cassandra.metrics");
-            add("instance:jmx_test_instance");
+            add("instance:jmx_first_instance");
         }};
 
         assertMetric("cassandra.pending_tasks.should_be100", tags, 5);
+
+        // Default behavior
+        tags = new ArrayList<String>() {{
+            add("type:ColumnFamily");
+            add("type:ColumnFamily");
+            add("keyspace:MyKeySpace");
+            add("jmx_domain:org.apache.cassandra.metrics");
+            add("instance:jmx_second_instance");
+            add("name:PendingTasks");
+        }};
+
+        assertMetric("cassandra.metrics.should_be1000", tags, 6);
     }
 
     @Test

src/test/resources/jmx_cassandra.yaml

@@ -2,9 +2,17 @@ init_config:
 
 instances:
     -   process_name_regex: .*surefire.*
-        name: jmx_test_instance
+        name: jmx_first_instance
+        cassandra_aliasing: true
         conf:
             - include:
                bean: org.apache.cassandra.metrics:keyspace=MyKeySpace,type=ColumnFamily,scope=MyColumnFamily,name=PendingTasks
                attribute:
                     - ShouldBe100
+    -   process_name_regex: .*surefire.*
+        name: jmx_second_instance
+        conf:
+            - include:
+               bean: org.apache.cassandra.metrics:keyspace=MyKeySpace,type=ColumnFamily,scope=MyColumnFamily,name=PendingTasks
+               attribute:
+                    - ShouldBe1000