Added overall CacheStatsResponse object packaging all 5 metrics

Signed-off-by: Peter Alfonsi <[email protected]>

server/src/main/java/org/opensearch/common/cache/stats/CacheStats.java

@@ -8,7 +8,7 @@
 
 package org.opensearch.common.cache.stats;
 
-import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.util.List;
 
@@ -18,7 +18,28 @@
  * When updating stats, we take in the list of dimensions associated with the key/value pair that caused the update.
  * This allows us to aggregate stats by dimension when accessing them.
  */
-public interface CacheStats extends CacheStatsBase { // TODO: Make this extend ToXContentFragment too
+public interface CacheStats extends Writeable {
+
+    // Methods to get all 5 values at once, either in total or for a specific set of dimensions.
+    CacheStatsResponse getTotalStats();
+    CacheStatsResponse getStatsByDimensions(List<CacheStatsDimension> dimensions);
+
+    // Methods to get total values.
+    long getTotalHits();
+    long getTotalMisses();
+    long getTotalEvictions();
+    long getTotalMemorySize();
+    long getTotalEntries();
+
+    // Methods to get values for a specific set of dimensions.
+    // Returns the sum of values for cache entries that match all dimensions in the list.
+    long getHitsByDimensions(List<CacheStatsDimension> dimensions);
+    long getMissesByDimensions(List<CacheStatsDimension> dimensions);
+    long getEvictionsByDimensions(List<CacheStatsDimension> dimensions);
+    long getMemorySizeByDimensions(List<CacheStatsDimension> dimensions);
+    long getEntriesByDimensions(List<CacheStatsDimension> dimensions);
+
+
     void incrementHitsByDimensions(List<CacheStatsDimension> dimensions);
     void incrementMissesByDimensions(List<CacheStatsDimension> dimensions);
     void incrementEvictionsByDimensions(List<CacheStatsDimension> dimensions);

server/src/main/java/org/opensearch/common/cache/stats/CacheStatsResponse.java

@@ -0,0 +1,28 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.cache.stats;
+
+/**
+ * A class containing the 5 metrics tracked by a CacheStats object.
+ */
+public class CacheStatsResponse { // TODO: Make this extend ToXContent.
+    public final long hits;
+    public final long misses;
+    public final long evictions;
+    public final long memorySize;
+    public final long entries;
+
+    public CacheStatsResponse(long hits, long misses, long evictions, long memorySize, long entries) {
+        this.hits = hits;
+        this.misses = misses;
+        this.evictions = evictions;
+        this.memorySize = memorySize;
+        this.entries = entries;
+    }
+}

server/src/main/java/org/opensearch/common/cache/stats/SingleDimensionCacheStats.java

@@ -84,6 +84,22 @@ public SingleDimensionCacheStats(StreamInput in) throws IOException {
         this.tierDimensionValue = in.readString();
     }
 
+    @Override
+    public CacheStatsResponse getTotalStats() {
+        return new CacheStatsResponse(getTotalHits(), getTotalMisses(), getTotalEvictions(), getTotalMemorySize(), getTotalEntries());
+    }
+
+    @Override
+    public CacheStatsResponse getStatsByDimensions(List<CacheStatsDimension> dimensions) {
+        return new CacheStatsResponse(
+            getHitsByDimensions(dimensions),
+            getMissesByDimensions(dimensions),
+            getEvictionsByDimensions(dimensions),
+            getMemorySizeByDimensions(dimensions),
+            getEntriesByDimensions(dimensions)
+        );
+    }
+
     @Override
     public long getTotalHits() {
         return this.totalHits.count();

server/src/main/java/org/opensearch/common/cache/tier/TieredSpilloverCacheStats.java

@@ -10,6 +10,7 @@
 
 import org.opensearch.common.cache.stats.CacheStats;
 import org.opensearch.common.cache.stats.CacheStatsDimension;
+import org.opensearch.common.cache.stats.CacheStatsResponse;
 import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
@@ -30,6 +31,16 @@ public void writeTo(StreamOutput out) throws IOException {
 
     }
 
+    @Override
+    public CacheStatsResponse getTotalStats() {
+        return null;
+    }
+
+    @Override
+    public CacheStatsResponse getStatsByDimensions(List<CacheStatsDimension> dimensions) {
+        return null;
+    }
+
     @Override
     public long getTotalHits() {
         return 0;

server/src/test/java/org/opensearch/common/cache/stats/SingleDimensionCacheStatsTests.java

@@ -170,23 +170,42 @@ private void checkShardResults(StatsAndExpectedResults statsAndExpectedResults)
             String shardIdString = String.valueOf(shardId);
             CacheStatsDimension dimension = getDim(shardId);
 
+            // Check the individual metric getters
             assertEquals((long) expectedResults.get("hits").get(shardIdString), stats.getHitsByDimensions(List.of(dimension)));
             assertEquals((long) expectedResults.get("misses").get(shardIdString), stats.getMissesByDimensions(List.of(dimension)));
             assertEquals((long) expectedResults.get("evictions").get(shardIdString), stats.getEvictionsByDimensions(List.of(dimension)));
             assertEquals((long) expectedResults.get("memory_size").get(shardIdString), stats.getMemorySizeByDimensions(List.of(dimension)));
             assertEquals((long) expectedResults.get("entries").get(shardIdString), stats.getEntriesByDimensions(List.of(dimension)));
+
+            // Check the total metric getter
+            CacheStatsResponse response = stats.getStatsByDimensions(List.of(dimension));
+            assertEquals((long) expectedResults.get("hits").get(shardIdString), response.hits);
+            assertEquals((long) expectedResults.get("misses").get(shardIdString), response.misses);
+            assertEquals((long) expectedResults.get("evictions").get(shardIdString), response.evictions);
+            assertEquals((long) expectedResults.get("memory_size").get(shardIdString), response.memorySize);
+            assertEquals((long) expectedResults.get("entries").get(shardIdString), response.entries);
         }
     }
 
     private void checkTotalResults(StatsAndExpectedResults statsAndExpectedResults) {
         // check resulting total values are what we expect
         Map<String, Map<String, Long>> expectedResults = statsAndExpectedResults.expectedShardResults;
         SingleDimensionCacheStats stats = statsAndExpectedResults.stats;
+
+        // Check the individual metric getters
         assertEquals(sumMap(expectedResults.get("hits")), stats.getTotalHits());
         assertEquals(sumMap(expectedResults.get("misses")), stats.getTotalMisses());
         assertEquals(sumMap(expectedResults.get("evictions")), stats.getTotalEvictions());
         assertEquals(sumMap(expectedResults.get("memory_size")), stats.getTotalMemorySize());
         assertEquals(sumMap(expectedResults.get("entries")), stats.getTotalEntries());
+
+        // Check the total metric getter
+        CacheStatsResponse totalResponse = stats.getTotalStats();
+        assertEquals(sumMap(expectedResults.get("hits")), totalResponse.hits);
+        assertEquals(sumMap(expectedResults.get("misses")), totalResponse.misses);
+        assertEquals(sumMap(expectedResults.get("evictions")), totalResponse.evictions);
+        assertEquals(sumMap(expectedResults.get("memory_size")), totalResponse.memorySize);
+        assertEquals(sumMap(expectedResults.get("entries")), totalResponse.entries);
     }
 
     // Convenience class to allow reusing setup code across tests