Improve Node and Metric interface to support conditional metric retrieval (#1115)

* Add detailsOnCondition method in Metric interface to filter MetricNode within the time condition.
* Add rawMetricsInMin method in Node interface, which will retrieve and generate metric items from the min-level sliding window on condition.
* Add test cases for detailsOnCondition.

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

sentinel-core/src/main/java/com/alibaba/csp/sentinel/node/Node.java

@@ -15,11 +15,13 @@
  */
 package com.alibaba.csp.sentinel.node;
 
+import java.util.List;
 import java.util.Map;
 
 import com.alibaba.csp.sentinel.Entry;
 import com.alibaba.csp.sentinel.node.metric.MetricNode;
 import com.alibaba.csp.sentinel.slots.statistic.metric.DebugSupport;
+import com.alibaba.csp.sentinel.util.function.Predicate;
 
 /**
  * Holds real-time statistics for resources.
@@ -146,6 +148,15 @@ public interface Node extends OccupySupport, DebugSupport {
      */
     Map<Long, MetricNode> metrics();
 
+    /**
+     * Fetch all raw metric items that satisfies the time predicate.
+     *
+     * @param timePredicate time predicate
+     * @return raw metric items that satisfies the time predicate
+     * @since 1.7.0
+     */
+    List<MetricNode> rawMetricsInMin(Predicate<Long> timePredicate);
+
     /**
      * Add pass count.
      *

sentinel-core/src/main/java/com/alibaba/csp/sentinel/node/StatisticNode.java

@@ -20,6 +20,7 @@ import com.alibaba.csp.sentinel.slots.statistic.base.LongAdder;
 import com.alibaba.csp.sentinel.slots.statistic.metric.ArrayMetric;
 import com.alibaba.csp.sentinel.slots.statistic.metric.Metric;
 import com.alibaba.csp.sentinel.util.TimeUtil;
+import com.alibaba.csp.sentinel.util.function.Predicate;
 
 import java.util.List;
 import java.util.Map;
@@ -131,6 +132,11 @@ public class StatisticNode implements Node {
         return metrics;
     }
 
+    @Override
+    public List<MetricNode> rawMetricsInMin(Predicate<Long> timePredicate) {
+        return rollingCounterInMinute.detailsOnCondition(timePredicate);
+    }
+
     private boolean isNodeInTime(MetricNode node, long currentTime) {
         return node.getTimestamp() > lastFetchTime && node.getTimestamp() < currentTime;
     }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/ArrayMetric.java

@@ -25,6 +25,7 @@ import com.alibaba.csp.sentinel.slots.statistic.base.LeapArray;
 import com.alibaba.csp.sentinel.slots.statistic.data.MetricBucket;
 import com.alibaba.csp.sentinel.slots.statistic.base.WindowWrap;
 import com.alibaba.csp.sentinel.slots.statistic.metric.occupy.OccupiableBucketLeapArray;
+import com.alibaba.csp.sentinel.util.function.Predicate;
 
 /**
  * The basic metric class in Sentinel using a {@link BucketLeapArray} internal.
@@ -153,33 +154,56 @@ public class ArrayMetric implements Metric {
 
     @Override
     public List<MetricNode> details() {
-        List<MetricNode> details = new ArrayList<MetricNode>();
+        List<MetricNode> details = new ArrayList<>();
         data.currentWindow();
         List<WindowWrap<MetricBucket>> list = data.list();
         for (WindowWrap<MetricBucket> window : list) {
             if (window == null) {
                 continue;
             }
-            MetricNode node = new MetricNode();
-            node.setBlockQps(window.value().block());
-            node.setExceptionQps(window.value().exception());
-            node.setPassQps(window.value().pass());
-            long successQps = window.value().success();
-            node.setSuccessQps(successQps);
-            if (successQps != 0) {
-                node.setRt(window.value().rt() / successQps);
-            } else {
-                node.setRt(window.value().rt());
+
+            details.add(fromBucket(window));
+        }
+
+        return details;
+    }
+
+    @Override
+    public List<MetricNode> detailsOnCondition(Predicate<Long> timePredicate) {
+        List<MetricNode> details = new ArrayList<>();
+        data.currentWindow();
+        List<WindowWrap<MetricBucket>> list = data.list();
+        for (WindowWrap<MetricBucket> window : list) {
+            if (window == null) {
+                continue;
+            }
+            if (timePredicate != null && !timePredicate.test(window.windowStart())) {
+                continue;
             }
-            node.setTimestamp(window.windowStart());
-            node.setOccupiedPassQps(window.value().occupiedPass());
 
-            details.add(node);
+            details.add(fromBucket(window));
         }
 
         return details;
     }
 
+    private MetricNode fromBucket(WindowWrap<MetricBucket> wrap) {
+        MetricNode node = new MetricNode();
+        node.setBlockQps(wrap.value().block());
+        node.setExceptionQps(wrap.value().exception());
+        node.setPassQps(wrap.value().pass());
+        long successQps = wrap.value().success();
+        node.setSuccessQps(successQps);
+        if (successQps != 0) {
+            node.setRt(wrap.value().rt() / successQps);
+        } else {
+            node.setRt(wrap.value().rt());
+        }
+        node.setTimestamp(wrap.windowStart());
+        node.setOccupiedPassQps(wrap.value().occupiedPass());
+        return node;
+    }
+
     @Override
     public MetricBucket[] windows() {
         data.currentWindow();

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/Metric.java

@@ -19,6 +19,7 @@ import java.util.List;
 
 import com.alibaba.csp.sentinel.node.metric.MetricNode;
 import com.alibaba.csp.sentinel.slots.statistic.data.MetricBucket;
+import com.alibaba.csp.sentinel.util.function.Predicate;
 
 /**
  * Represents a basic structure recording invocation metrics of protected resources.
@@ -84,6 +85,15 @@ public interface Metric extends DebugSupport {
      */
     List<MetricNode> details();
 
+    /**
+     * Generate aggregated metric items that satisfies the time predicate.
+     *
+     * @param timePredicate time predicate
+     * @return aggregated metric items
+     * @since 1.7.0
+     */
+    List<MetricNode> detailsOnCondition(Predicate<Long> timePredicate);
+
     /**
      * Get the raw window array.
      *

sentinel-core/src/test/java/com/alibaba/csp/sentinel/slots/statistic/metric/ArrayMetricTest.java

@@ -16,9 +16,14 @@
 package com.alibaba.csp.sentinel.slots.statistic.metric;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 
+import com.alibaba.csp.sentinel.node.metric.MetricNode;
+import com.alibaba.csp.sentinel.slots.statistic.MetricEvent;
 import com.alibaba.csp.sentinel.slots.statistic.base.WindowWrap;
 import com.alibaba.csp.sentinel.slots.statistic.data.MetricBucket;
+import com.alibaba.csp.sentinel.util.function.Predicate;
 
 import org.junit.Test;
 
@@ -38,7 +43,8 @@ public class ArrayMetricTest {
     @Test
     public void testOperateArrayMetric() {
         BucketLeapArray leapArray = mock(BucketLeapArray.class);
-        final WindowWrap<MetricBucket> windowWrap = new WindowWrap<MetricBucket>(windowLengthInMs, 0, new MetricBucket());
+        final WindowWrap<MetricBucket> windowWrap = new WindowWrap<MetricBucket>(windowLengthInMs, 0,
+            new MetricBucket());
         when(leapArray.currentWindow()).thenReturn(windowWrap);
         when(leapArray.values()).thenReturn(new ArrayList<MetricBucket>() {{ add(windowWrap.value()); }});
 
@@ -70,4 +76,45 @@ public class ArrayMetricTest {
         assertEquals(expectedException, metric.exception());
         assertEquals(expectedRt, metric.rt());
     }
-}
+
+    @Test
+    public void testGetMetricDetailsOnCondition() {
+        BucketLeapArray leapArray = mock(BucketLeapArray.class);
+        // Mock interval=2s, sampleCount=2
+        final WindowWrap<MetricBucket> w1 = new WindowWrap<>(windowLengthInMs, 500,
+            new MetricBucket().add(MetricEvent.PASS, 1));
+        final WindowWrap<MetricBucket> w2 = new WindowWrap<>(windowLengthInMs, 1000,
+            new MetricBucket().add(MetricEvent.PASS, 2));
+        final WindowWrap<MetricBucket> w3 = new WindowWrap<>(windowLengthInMs, 1500,
+            new MetricBucket().add(MetricEvent.PASS, 3));
+        final WindowWrap<MetricBucket> w4 = new WindowWrap<>(windowLengthInMs, 2000,
+            new MetricBucket().add(MetricEvent.PASS, 4));
+        List<WindowWrap<MetricBucket>> buckets = Arrays.asList(w1, w2, w3, w4);
+        when(leapArray.currentWindow()).thenReturn(w4);
+        when(leapArray.list()).thenReturn(buckets);
+
+        ArrayMetric metric = new ArrayMetric(leapArray);
+
+        // Empty condition -> retrieve all
+        assertEquals(4, metric.detailsOnCondition(null).size());
+        // Normal condition
+        List<MetricNode> metricNodes = metric.detailsOnCondition(new Predicate<Long>() {
+            @Override
+            public boolean test(Long t) {
+                return t >= 1500;
+            }
+        });
+        assertEquals(2, metricNodes.size());
+        assertEquals(3, metricNodes.get(0).getPassQps());
+        assertEquals(4, metricNodes.get(1).getPassQps());
+
+        // Future condition
+        metricNodes = metric.detailsOnCondition(new Predicate<Long>() {
+            @Override
+            public boolean test(Long t) {
+                return t >= 2500;
+            }
+        });
+        assertEquals(0, metricNodes.size());
+    }
+}