Performance Metrics service and manager added

@@ -11,6 +11,7 @@
         <bundle>mvn:io.netty/netty/3.9.2.Final</bundle>
         <bundle>mvn:io.netty/netty/3.9.2.Final</bundle>
 
 
         <bundle>mvn:com.hazelcast/hazelcast/3.3</bundle>
         <bundle>mvn:com.hazelcast/hazelcast/3.3</bundle>
+        <bundle>mvn:com.codahale.metrics/metrics-core/3.0.2</bundle>
         <bundle>mvn:com.eclipsesource.minimal-json/minimal-json/0.9.1</bundle>
         <bundle>mvn:com.eclipsesource.minimal-json/minimal-json/0.9.1</bundle>
 
 
         <bundle>mvn:com.esotericsoftware.kryo/kryo/2.24.0</bundle>
         <bundle>mvn:com.esotericsoftware.kryo/kryo/2.24.0</bundle>

@@ -55,6 +55,11 @@
             <groupId>org.objenesis</groupId>
             <groupId>org.objenesis</groupId>
             <artifactId>objenesis</artifactId>
             <artifactId>objenesis</artifactId>
         </dependency>
         </dependency>
+        <dependency>
+            <groupId>com.codahale.metrics</groupId>
+            <artifactId>metrics-core</artifactId>
+            <version>3.0.2</version>
+        </dependency>
     </dependencies>
     </dependencies>
 
 
 </project>
 </project>

+package org.onlab.metrics;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+/**
+ * Components to register for metrics.
+ */
+public class MetricsComponent implements MetricsComponentRegistry {
+    private final String name;
+
+    /**
+     * Registry to hold the Features defined in this Component.
+     */
+    private final ConcurrentMap<String, MetricsFeature> featuresRegistry =
+            new ConcurrentHashMap<>();
+
+    /**
+     * Constructs a component from a name.
+     *
+     * @param newName name of the component
+     */
+    MetricsComponent(final String newName) {
+        name = newName;
+    }
+
+    @Override public String getName() {
+        return name;
+    }
+
+    @Override public MetricsFeature registerFeature(final String featureName) {
+        MetricsFeature feature = featuresRegistry.get(featureName);
+        if (feature == null) {
+            final MetricsFeature createdFeature = new MetricsFeature(featureName);
+            feature = featuresRegistry.putIfAbsent(featureName, createdFeature);
+            if (feature == null) {
+                feature = createdFeature;
+            }
+        }
+        return feature;
+    }
+}

+package org.onlab.metrics;
+
+/**
+ * Registry Entry for Metrics Components.
+ */
+public interface MetricsComponentRegistry {
+    String getName();
+
+    MetricsFeature registerFeature(String featureName);
+}

+package org.onlab.metrics;
+
+/**
+ * Features to tag metrics.
+ */
+public class MetricsFeature {
+    private final String name;
+
+    /**
+     * Constructs a Feature from a name.
+     *
+     * @param newName name of the Feature
+     */
+    MetricsFeature(final String newName) {
+        name = newName;
+    }
+
+    public String getName() {
+        return name;
+    }
+}

+package org.onlab.metrics;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+import com.codahale.metrics.Counter;
+import com.codahale.metrics.Gauge;
+import com.codahale.metrics.Histogram;
+import com.codahale.metrics.Meter;
+import com.codahale.metrics.Metric;
+import com.codahale.metrics.MetricFilter;
+import com.codahale.metrics.MetricRegistry;
+import com.codahale.metrics.Timer;
+
+/**
+ * This class holds the Metrics registry for ONOS.
+ * All metrics (Counter, Histogram, Timer, Meter, Gauge) use a hierarchical
+ * string-based naming scheme: COMPONENT.FEATURE.NAME.
+ * Example: "Topology.Counters.TopologyUpdates".
+ * The COMPONENT and FEATURE names have to be registered in advance before
+ * a metric can be created. Example:
+ * <pre>
+ *   <code>
+ *     private final MetricsManager.MetricsComponent COMPONENT =
+ *         MetricsManager.registerComponent("Topology");
+ *     private final MetricsManager.MetricsFeature FEATURE =
+ *         COMPONENT.registerFeature("Counters");
+ *     private final Counter counterTopologyUpdates =
+ *         MetricsManager.createCounter(COMPONENT, FEATURE, "TopologyUpdates");
+ *   </code>
+ * </pre>
+ * Gauges are slightly different because they are not created directly in
+ * this class, but are allocated by the caller and passed in for registration:
+ * <pre>
+ *   <code>
+ *     private final Gauge<Long> gauge =
+ *         new {@literal Gauge<Long>}() {
+ *             {@literal @}Override
+ *             public Long getValue() {
+ *                 return gaugeValue;
+ *             }
+ *         };
+ *     MetricsManager.registerMetric(COMPONENT, FEATURE, GAUGE_NAME, gauge);
+ *   </code>
+ * </pre>
+ */
+public final class MetricsManager implements MetricsService {
+
+    /**
+     * Registry to hold the Components defined in the system.
+     */
+    private ConcurrentMap<String, MetricsComponent> componentsRegistry =
+            new ConcurrentHashMap<>();
+
+    /**
+     * Registry for the Metrics objects created in the system.
+     */
+    private final MetricRegistry metricsRegistry = new MetricRegistry();
+
+    /**
+     * Hide constructor.  The only way to get the registry is through the
+     * singleton getter.
+     */
+    private MetricsManager() {}
+
+    /**
+     * Registers a component.
+     *
+     * @param name name of the Component to register
+     * @return MetricsComponent object that can be used to create Metrics.
+     */
+  public MetricsComponent registerComponent(final String name) {
+        MetricsComponent component = componentsRegistry.get(name);
+        if (component == null) {
+            final MetricsComponent createdComponent = new MetricsComponent(name);
+            component = componentsRegistry.putIfAbsent(name, createdComponent);
+            if (component == null) {
+                component = createdComponent;
+            }
+        }
+        return component;
+    }
+
+    /**
+     * Generates a name for a Metric from its component and feature.
+     *
+     * @param component component the metric is defined in
+     * @param feature feature the metric is defined in
+     * @param metricName local name of the metric
+     *
+     * @return full name of the metric
+     */
+  public String generateName(final MetricsComponent component,
+                                      final MetricsFeature feature,
+                                      final String metricName) {
+        return MetricRegistry.name(component.getName(),
+                                   feature.getName(),
+                                   metricName);
+    }
+
+    /**
+     * Creates a Counter metric.
+     *
+     * @param component component the Counter is defined in
+     * @param feature feature the Counter is defined in
+     * @param metricName local name of the metric
+     * @return the created Counter Meteric
+     */
+  public Counter createCounter(final MetricsComponent component,
+                                        final MetricsFeature feature,
+                                        final String metricName) {
+        final String name = generateName(component, feature, metricName);
+        return metricsRegistry.counter(name);
+    }
+
+    /**
+     * Creates a Histogram metric.
+     *
+     * @param component component the Histogram is defined in
+     * @param feature feature the Histogram is defined in
+     * @param metricName local name of the metric
+     * @return the created Histogram Metric
+     */
+  public Histogram createHistogram(final MetricsComponent component,
+                                            final MetricsFeature feature,
+                                            final String metricName) {
+        final String name = generateName(component, feature, metricName);
+        return metricsRegistry.histogram(name);
+    }
+
+    /**
+     * Creates a Timer metric.
+     *
+     * @param component component the Timer is defined in
+     * @param feature feature the Timeer is defined in
+     * @param metricName local name of the metric
+     * @return the created Timer Metric
+     */
+  public Timer createTimer(final MetricsComponent component,
+                                    final MetricsFeature feature,
+                                    final String metricName) {
+        final String name = generateName(component, feature, metricName);
+        return metricsRegistry.timer(name);
+    }
+
+    /**
+     * Creates a Meter metric.
+     *
+     * @param component component the Meter is defined in
+     * @param feature feature the Meter is defined in
+     * @param metricName local name of the metric
+     * @return the created Meter Metric
+     */
+  public Meter createMeter(final MetricsComponent component,
+                                    final MetricsFeature feature,
+                                    final String metricName) {
+        final String name = generateName(component, feature, metricName);
+        return metricsRegistry.meter(name);
+    }
+
+    /**
+     * Registers an already created Metric.  This is used for situation where a
+     * caller needs to allocate its own Metric, but still register it with the
+     * system.
+     *
+     * @param <T> Metric type
+     * @param component component the Metric is defined in
+     * @param feature feature the Metric is defined in
+     * @param metricName local name of the metric
+     * @param metric Metric to register
+     * @return the registered Metric
+     */
+  public <T extends Metric> T registerMetric(
+                                        final MetricsComponent component,
+                                        final MetricsFeature feature,
+                                        final String metricName,
+                                        final T metric) {
+        final String name = generateName(component, feature, metricName);
+        metricsRegistry.register(name, metric);
+        return metric;
+    }
+
+    /**
+     * Fetches the existing Timers.
+     *
+     * @param filter filter to use to select Timers
+     * @return a map of the Timers that match the filter, with the key as the
+     *         name String to the Timer.
+     */
+  public Map<String, Timer> getTimers(final MetricFilter filter) {
+        return metricsRegistry.getTimers(filter);
+    }
+
+    /**
+     * Fetches the existing Gauges.
+     *
+     * @param filter filter to use to select Gauges
+     * @return a map of the Gauges that match the filter, with the key as the
+     *         name String to the Gauge.
+     */
+    @SuppressWarnings("rawtypes")
+  public Map<String, Gauge> getGauges(final MetricFilter filter) {
+        return metricsRegistry.getGauges(filter);
+    }
+
+    /**
+     * Fetches the existing Counters.
+     *
+     * @param filter filter to use to select Counters
+     * @return a map of the Counters that match the filter, with the key as the
+     *         name String to the Counter.
+     */
+  public Map<String, Counter> getCounters(final MetricFilter filter) {
+        return metricsRegistry.getCounters(filter);
+    }
+
+    /**
+     * Fetches the existing Meters.
+     *
+     * @param filter filter to use to select Meters
+     * @return a map of the Meters that match the filter, with the key as the
+     *         name String to the Meter.
+     */
+  public Map<String, Meter> getMeters(final MetricFilter filter) {
+        return metricsRegistry.getMeters(filter);
+    }
+
+    /**
+     * Fetches the existing Histograms.
+     *
+     * @param filter filter to use to select Histograms
+     * @return a map of the Histograms that match the filter, with the key as the
+     *         name String to the Histogram.
+     */
+  public Map<String, Histogram> getHistograms(final MetricFilter filter) {
+        return metricsRegistry.getHistograms(filter);
+    }
+
+    /**
+     * Removes all Metrics that match a given filter.
+     *
+     * @param filter filter to use to select the Metrics to remove.
+     */
+  public void removeMatching(final MetricFilter filter) {
+        metricsRegistry.removeMatching(filter);
+    }
+}
+

+package org.onlab.metrics;
+
+import java.util.Map;
+
+import com.codahale.metrics.Counter;
+import com.codahale.metrics.Gauge;
+import com.codahale.metrics.Histogram;
+import com.codahale.metrics.Meter;
+import com.codahale.metrics.Metric;
+import com.codahale.metrics.MetricFilter;
+import com.codahale.metrics.Timer;
+
+/**
+ * Metrics Service to collect metrics.
+ */
+interface MetricsService {
+
+    /**
+     * Registers a component.
+     *
+     * @param name name of the Component to register
+     * @return MetricsComponent object that can be used to create Metrics.
+     */
+    MetricsComponent registerComponent(String name);
+
+    /**
+     * Creates a Counter metric.
+     *
+     * @param component component the Counter is defined in
+     * @param feature feature the Counter is defined in
+     * @param metricName local name of the metric
+     * @return the created Counter Meteric
+     */
+    Counter createCounter(MetricsComponent component,
+            MetricsFeature feature,
+            String metricName);
+
+    /**
+     * Creates a Histogram metric.
+     *
+     * @param component component the Histogram is defined in
+     * @param feature feature the Histogram is defined in
+     * @param metricName local name of the metric
+     * @return the created Histogram Metric
+     */
+    Histogram createHistogram(MetricsComponent component,
+            MetricsFeature feature,
+            String metricName);
+
+    /**
+     * Creates a Timer metric.
+     *
+     * @param component component the Timer is defined in
+     * @param feature feature the Timer is defined in
+     * @param metricName local name of the metric
+     * @return the created Timer Metric
+     */
+    Timer createTimer(MetricsComponent component,
+            MetricsFeature feature,
+            String metricName);
+
+    /**
+     * Registers an already created Metric.  This is used for situation where a
+     * caller needs to allocate its own Metric, but still register it with the
+     * system.
+     *
+     * @param <T> Metric type
+     * @param component component the Metric is defined in
+     * @param feature feature the Metric is defined in
+     * @param metricName local name of the metric
+     * @param metric Metric to register
+     * @return the registered Metric
+     */
+     <T extends Metric> T registerMetric(
+             MetricsComponent component,
+             MetricsFeature feature,
+             String metricName,
+             T metric);
+
+    /**
+     * Fetches the existing Timers.
+     *
+     * @param filter filter to use to select Timers
+     * @return a map of the Timers that match the filter, with the key as the
+     *         name String to the Timer.
+     */
+     Map<String, Timer> getTimers(MetricFilter filter);
+
+    /**
+     * Fetches the existing Gauges.
+     *
+     * @param filter filter to use to select Gauges
+     * @return a map of the Gauges that match the filter, with the key as the
+     *         name String to the Gauge.
+     */
+     Map<String, Gauge> getGauges(MetricFilter filter);
+
+    /**
+     * Fetches the existing Counters.
+     *
+     * @param filter filter to use to select Counters
+     * @return a map of the Counters that match the filter, with the key as the
+     *         name String to the Counter.
+     */
+     Map<String, Counter> getCounters(MetricFilter filter);
+
+    /**
+     * Fetches the existing Meters.
+     *
+     * @param filter filter to use to select Meters
+     * @return a map of the Meters that match the filter, with the key as the
+     *         name String to the Meter.
+     */
+     Map<String, Meter> getMeters(MetricFilter filter);
+
+    /**
+     * Fetches the existing Histograms.
+     *
+     * @param filter filter to use to select Histograms
+     * @return a map of the Histograms that match the filter, with the key as the
+     *         name String to the Histogram.
+     */
+     Map<String, Histogram> getHistograms(MetricFilter filter);
+    /**
+     * Removes all Metrics that match a given filter.
+     *
+     * @param filter filter to use to select the Metrics to remove.
+     */
+     void removeMatching(MetricFilter filter);
+
+}

+/**
+ * Misc utils for various performance metrics.
+ */
+package org.onlab.metrics;