commit 14c4651a09ac47a3a71cdf7e284a9f752137dfa3
author Ray Milkey <ray@onlab.us> Tue Jul 08 18:30:31 2014 -0700
committer Gerrit Code Review <gerrit2@gerrit.onos.onlab.us> Wed Jul 09 12:59:47 2014 -0700
tree e105f65c8b6f532a7fb524f276812408aea663f9
parent dde5a0b45196c3ddbffdc6e58e32502e2732b416

Add a filter by name to Metrics REST API

Filter by name is accessed by putting an "ids" parameter in the
query string passed to the REST API.  Here are some examples:

/wm/onos/metrics
Fetches all metrics known by the system

/wm/onos/metrics?ids=timer1
Fetches just the metric named "timer1"

/wm/onos/metrics?ids=timer1,gauge2
Fetches the metric named "timer1" and the metric name "gauge2

Note that the object returned by this query is always the Meteric Resource Object.
If a filter is applied, the values in the structure will be filtered, but the
object returned is the same."

Change-Id: I61352c78d19a22a1e99d2fdbdb59e3c064125cbf

src/main/java/net/onrc/onos/core/metrics/MetricsResource.java

diff --git a/src/main/java/net/onrc/onos/core/metrics/MetricsResource.java b/src/main/java/net/onrc/onos/core/metrics/MetricsResource.java
index 64b7996..40feaaa 100644
--- a/src/main/java/net/onrc/onos/core/metrics/MetricsResource.java
+++ b/src/main/java/net/onrc/onos/core/metrics/MetricsResource.java
@@ -1,16 +1,20 @@
 package net.onrc.onos.core.metrics;
 
+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;
-import com.codahale.metrics.Counter;
-import com.codahale.metrics.Meter;
-import com.codahale.metrics.Histogram;
 import org.restlet.representation.Representation;
 import org.restlet.resource.Get;
 import org.restlet.resource.ServerResource;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 
@@ -20,6 +24,42 @@
 public class MetricsResource extends ServerResource {
 
     /**
+     * Metric filter to allow selecting metrics by name.
+     */
+    private static class MetricNameFilter implements MetricFilter {
+        final HashSet<String> names;
+
+        /**
+         * Hide default constructor.
+         */
+        @SuppressWarnings("unused")
+        private MetricNameFilter() {
+            names = null;
+        }
+
+        /**
+         * Initializes a filter for the given name list.
+         *
+         * @param nameListString comma separated list of strings of the
+         *                       names of metrics to query
+         */
+        public MetricNameFilter(final String nameListString) {
+
+            if (nameListString == null) {
+                names = null;
+            } else {
+                List<String> nameList = Arrays.asList(nameListString.split(","));
+                names = new HashSet<>();
+                names.addAll(nameList);
+            }
+        }
+
+        @Override
+        public boolean matches(String s, Metric metric) {
+            return names == null || names.contains(s);
+        }
+    }
+    /**
      * REST API to get all of the system's metrics.
      *
      * @return a Representation object containing the metrics
@@ -41,36 +81,40 @@
         final List<MetricsObjectResource.HistogramObjectResource> histograms =
                 new ArrayList<>();
 
+        final String metricIdsString = getQuery().getValues("ids");
+
+        final MetricFilter filter = new MetricNameFilter(metricIdsString);
+
         for (final Map.Entry<String, Timer> timer :
-             registry.getTimers().entrySet()) {
+             registry.getTimers(filter).entrySet()) {
             timers.add(new MetricsObjectResource.TimerObjectResource(
                     timer.getKey(), timer.getValue()));
         }
         result.setTimers(timers);
 
         for (final Map.Entry<String, Gauge> gauge :
-             registry.getGauges().entrySet()) {
+             registry.getGauges(filter).entrySet()) {
             gauges.add(new MetricsObjectResource.GaugeObjectResource(
                     gauge.getKey(), gauge.getValue()));
         }
         result.setGauges(gauges);
 
         for (final Map.Entry<String, Counter> counter :
-             registry.getCounters().entrySet()) {
+             registry.getCounters(filter).entrySet()) {
             counters.add(new MetricsObjectResource.CounterObjectResource(
                     counter.getKey(), counter.getValue()));
         }
         result.setCounters(counters);
 
         for (final Map.Entry<String, Meter> meter :
-             registry.getMeters().entrySet()) {
+             registry.getMeters(filter).entrySet()) {
             meters.add(new MetricsObjectResource.MeterObjectResource(
                     meter.getKey(), meter.getValue()));
         }
         result.setMeters(meters);
 
         for (final Map.Entry<String, Histogram> histogram :
-             registry.getHistograms().entrySet()) {
+             registry.getHistograms(filter).entrySet()) {
             histograms.add(new MetricsObjectResource.HistogramObjectResource(
                     histogram.getKey(), histogram.getValue()));
         }