Add data models for health stats API

src/main/java/org/opensearch/plugin/insights/core/service/QueryInsightsService.java

@@ -9,6 +9,7 @@
 package org.opensearch.plugin.insights.core.service;
 
 import static org.opensearch.plugin.insights.settings.QueryInsightsSettings.DEFAULT_GROUPING_TYPE;
+import static org.opensearch.plugin.insights.settings.QueryInsightsSettings.QUERY_INSIGHTS_EXECUTOR;
 import static org.opensearch.plugin.insights.settings.QueryInsightsSettings.getExporterSettings;
 
 import java.io.IOException;
@@ -18,6 +19,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.LinkedBlockingQueue;
+import java.util.stream.Collectors;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.client.Client;
@@ -33,6 +35,8 @@
 import org.opensearch.plugin.insights.rules.model.GroupingType;
 import org.opensearch.plugin.insights.rules.model.MetricType;
 import org.opensearch.plugin.insights.rules.model.SearchQueryRecord;
+import org.opensearch.plugin.insights.rules.model.healthStats.QueryInsightsHealthStats;
+import org.opensearch.plugin.insights.rules.model.healthStats.TopQueriesHealthStats;
 import org.opensearch.plugin.insights.settings.QueryInsightsSettings;
 import org.opensearch.telemetry.metrics.MetricsRegistry;
 import org.opensearch.threadpool.Scheduler;
@@ -439,4 +443,20 @@ protected void doClose() throws IOException {
         queryInsightsExporterFactory.closeAllExporters();
         queryInsightsReaderFactory.closeAllReaders();
     }
+
+    /**
+     * Get health stats for query insights services
+     *
+     * @return QueryInsightsHealthStats
+     */
+    public QueryInsightsHealthStats getHealthStats() {
+        Map<MetricType, TopQueriesHealthStats> topQueriesHealthStatsMap = topQueriesServices.entrySet()
+            .stream()
+            .collect(Collectors.toMap(Map.Entry::getKey, entry -> entry.getValue().getHealthStats()));
+        return new QueryInsightsHealthStats(
+            threadPool.info(QUERY_INSIGHTS_EXECUTOR),
+            this.queryRecordsQueue.size(),
+            topQueriesHealthStatsMap
+        );
+    }
 }

src/main/java/org/opensearch/plugin/insights/core/service/TopQueriesService.java

@@ -49,6 +49,7 @@
 import org.opensearch.plugin.insights.rules.model.GroupingType;
 import org.opensearch.plugin.insights.rules.model.MetricType;
 import org.opensearch.plugin.insights.rules.model.SearchQueryRecord;
+import org.opensearch.plugin.insights.rules.model.healthStats.TopQueriesHealthStats;
 import org.opensearch.plugin.insights.settings.QueryInsightsSettings;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -516,4 +517,13 @@ private void drain() {
         topQueriesHistorySnapshot.set(new ArrayList<>());
         topQueriesCurrentSnapshot.set(new ArrayList<>());
     }
+
+    /**
+     * Get top queries service health stats
+     *
+     * @return TopQueriesHealthStats
+     */
+    public TopQueriesHealthStats getHealthStats() {
+        return new TopQueriesHealthStats(this.topQueriesStore.size(), this.queryGrouper.getHealthStats());
+    }
 }

src/main/java/org/opensearch/plugin/insights/core/service/grouper/MinMaxHeapQueryGrouper.java

@@ -20,6 +20,7 @@
 import org.opensearch.plugin.insights.rules.model.GroupingType;
 import org.opensearch.plugin.insights.rules.model.MetricType;
 import org.opensearch.plugin.insights.rules.model.SearchQueryRecord;
+import org.opensearch.plugin.insights.rules.model.healthStats.QueryGrouperHealthStats;
 import org.opensearch.plugin.insights.settings.QueryInsightsSettings;
 
 /**
@@ -39,12 +40,12 @@ public class MinMaxHeapQueryGrouper implements QueryGrouper {
     /**
      * Metric type for the current grouping service
      */
-    private MetricType metricType;
+    private final MetricType metricType;
 
     /**
      * Aggregation type for the current grouping service
      */
-    private AggregationType aggregationType;
+    private final AggregationType aggregationType;
     /**
      * Map storing groupingId to Tuple containing Aggregate search query record and boolean.
      * SearchQueryRecord: Aggregate search query record to store the aggregate of a metric type based on the aggregation type..
@@ -53,18 +54,18 @@ public class MinMaxHeapQueryGrouper implements QueryGrouper {
      * boolean: True if the aggregate record is in the Top N queries priority query (min heap) and False if the aggregate
      * record is in the Max Heap
      */
-    private ConcurrentHashMap<String, Tuple<SearchQueryRecord, Boolean>> groupIdToAggSearchQueryRecord;
+    private final ConcurrentHashMap<String, Tuple<SearchQueryRecord, Boolean>> groupIdToAggSearchQueryRecord;
     /**
      * Min heap to keep track of the Top N query groups and is passed from TopQueriesService as the topQueriesStore
      */
-    private PriorityBlockingQueue<SearchQueryRecord> minHeapTopQueriesStore;
+    private final PriorityBlockingQueue<SearchQueryRecord> minHeapTopQueriesStore;
     /**
      * The Max heap is an overflow data structure used to manage records that exceed the capacity of the Min heap.
      * It stores all records not included in the Top N query results. When the aggregate measurement for one of these
      * records is updated and it now qualifies as part of the Top N, the record is moved from the Max heap to the Min heap,
      * and the records are rearranged accordingly.
      */
-    private PriorityBlockingQueue<SearchQueryRecord> maxHeapQueryStore;
+    private final PriorityBlockingQueue<SearchQueryRecord> maxHeapQueryStore;
 
     /**
      * Top N size based on the configuration set
@@ -80,11 +81,11 @@ public class MinMaxHeapQueryGrouper implements QueryGrouper {
     private int maxGroups;
 
     public MinMaxHeapQueryGrouper(
-        MetricType metricType,
-        GroupingType groupingType,
-        AggregationType aggregationType,
-        PriorityBlockingQueue<SearchQueryRecord> topQueriesStore,
-        int topNSize
+        final MetricType metricType,
+        final GroupingType groupingType,
+        final AggregationType aggregationType,
+        final PriorityBlockingQueue<SearchQueryRecord> topQueriesStore,
+        final int topNSize
     ) {
         this.groupingType = groupingType;
         this.metricType = metricType;
@@ -103,7 +104,7 @@ public MinMaxHeapQueryGrouper(
      * @return return the search query record that represents the group
      */
     @Override
-    public SearchQueryRecord add(SearchQueryRecord searchQueryRecord) {
+    public SearchQueryRecord add(final SearchQueryRecord searchQueryRecord) {
         if (groupingType == GroupingType.NONE) {
             throw new IllegalArgumentException("Do not use addQueryToGroup when GroupingType is None");
         }
@@ -120,8 +121,7 @@ public SearchQueryRecord add(SearchQueryRecord searchQueryRecord) {
         // Add to min PQ and promote to max
         // If max PQ is empty return else try to promote record from max to min
         if (!groupIdToAggSearchQueryRecord.containsKey(groupId)) {
-            boolean maxGroupsLimitReached = checkMaxGroupsLimitReached(groupId);
-            if (maxGroupsLimitReached) {
+            if (checkMaxGroupsLimitReached(groupId)) {
                 return null;
             }
             aggregateSearchQueryRecord = searchQueryRecord;
@@ -158,7 +158,7 @@ public void drain() {
      * @return grouping type changed
      */
     @Override
-    public boolean setGroupingType(GroupingType newGroupingType) {
+    public boolean setGroupingType(final GroupingType newGroupingType) {
         if (this.groupingType != newGroupingType) {
             this.groupingType = newGroupingType;
             drain();
@@ -183,7 +183,7 @@ public GroupingType getGroupingType() {
      * @return max groups changed
      */
     @Override
-    public boolean setMaxGroups(int maxGroups) {
+    public boolean setMaxGroups(final int maxGroups) {
         if (this.maxGroups != maxGroups) {
             this.maxGroups = maxGroups;
             drain();
@@ -197,17 +197,21 @@ public boolean setMaxGroups(int maxGroups) {
      * @param newSize new size
      */
     @Override
-    public void updateTopNSize(int newSize) {
+    public void updateTopNSize(final int newSize) {
         this.topNSize = newSize;
     }
 
-    private void addToMinPQ(SearchQueryRecord searchQueryRecord, String groupId) {
+    private void addToMinPQ(final SearchQueryRecord searchQueryRecord, final String groupId) {
         minHeapTopQueriesStore.add(searchQueryRecord);
         groupIdToAggSearchQueryRecord.put(groupId, new Tuple<>(searchQueryRecord, true));
         overflow();
     }
 
-    private void addAndPromote(SearchQueryRecord searchQueryRecord, SearchQueryRecord aggregateSearchQueryRecord, String groupId) {
+    private void addAndPromote(
+        final SearchQueryRecord searchQueryRecord,
+        final SearchQueryRecord aggregateSearchQueryRecord,
+        final String groupId
+    ) {
         Number measurementToAdd = searchQueryRecord.getMeasurement(metricType);
         aggregateSearchQueryRecord.addMeasurement(metricType, measurementToAdd);
         addToMinPQ(aggregateSearchQueryRecord, groupId);
@@ -228,7 +232,7 @@ private void overflow() {
         }
     }
 
-    private boolean checkMaxGroupsLimitReached(String groupId) {
+    private boolean checkMaxGroupsLimitReached(final String groupId) {
         if (maxGroups <= maxHeapQueryStore.size() && minHeapTopQueriesStore.size() >= topNSize) {
             log.warn(
                 "Exceeded [{}] setting threshold which is set at {}. Discarding new group with id {}.",
@@ -259,11 +263,11 @@ int numberOfTopGroups() {
     }
 
     /**
-     * Get groupingId. This should be query hashcode for SIMILARITY grouping and user_id for USER_ID grouping.
+     * Get groupingId. This should be the query hashcode for SIMILARITY grouping and user_id for USER_ID grouping.
      * @param searchQueryRecord record
      * @return Grouping Id
      */
-    private String getGroupingId(SearchQueryRecord searchQueryRecord) {
+    private String getGroupingId(final SearchQueryRecord searchQueryRecord) {
         switch (groupingType) {
             case SIMILARITY:
                 return searchQueryRecord.getAttributes().get(Attribute.QUERY_HASHCODE).toString();
@@ -273,4 +277,13 @@ private String getGroupingId(SearchQueryRecord searchQueryRecord) {
                 throw new IllegalArgumentException("The following grouping type is not supported : " + groupingType);
         }
     }
+
+    /**
+     * Get health stats of the MinMaxHeapQueryGrouperService
+     *
+     * @return QueryGrouperHealthStats
+     */
+    public QueryGrouperHealthStats getHealthStats() {
+        return new QueryGrouperHealthStats(this.groupIdToAggSearchQueryRecord.size(), this.maxHeapQueryStore.size());
+    }
 }

src/main/java/org/opensearch/plugin/insights/core/service/grouper/QueryGrouper.java

@@ -10,6 +10,7 @@
 
 import org.opensearch.plugin.insights.rules.model.GroupingType;
 import org.opensearch.plugin.insights.rules.model.SearchQueryRecord;
+import org.opensearch.plugin.insights.rules.model.healthStats.QueryGrouperHealthStats;
 
 /**
  * Interface for grouping search queries based on grouping type for the metric type.
@@ -57,4 +58,11 @@ public interface QueryGrouper {
      * @param topNSize the new top N size
      */
     void updateTopNSize(int topNSize);
+
+    /**
+     * Get health stats of the QueryGrouperService
+     *
+     * @return QueryGrouperHealthStats
+     */
+    QueryGrouperHealthStats getHealthStats();
 }

src/main/java/org/opensearch/plugin/insights/rules/model/MetricType.java

@@ -62,7 +62,7 @@ public static MetricType fromString(final String metricType) {
      * @param metricType the MetricType to write
      * @throws IOException IOException
      */
-    static void writeTo(final StreamOutput out, final MetricType metricType) throws IOException {
+    public static void writeTo(final StreamOutput out, final MetricType metricType) throws IOException {
         out.writeString(metricType.toString());
     }
 

src/main/java/org/opensearch/plugin/insights/rules/model/healthStats/QueryGrouperHealthStats.java

@@ -0,0 +1,92 @@
+/*
+ * 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.plugin.insights.rules.model.healthStats;
+
+import java.io.IOException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+/**
+ * Represents the health statistics of the query grouper.
+ */
+public class QueryGrouperHealthStats implements ToXContentFragment, Writeable {
+    private final int queryGroupCount;
+    private final int queryGroupHeapSize;
+    private static final String QUERY_GROUP_COUNT_TOTAL = "QueryGroupCount_Total";
+    private static final String QUERY_GROUP_COUNT_MAX_HEAP = "QueryGroupCount_MaxHeap";
+
+    /**
+     * Constructor to read QueryGrouperHealthStats from a StreamInput.
+     *
+     * @param in the StreamInput to read the QueryGrouperHealthStats from
+     * @throws IOException IOException
+     */
+    public QueryGrouperHealthStats(final StreamInput in) throws IOException {
+        this.queryGroupCount = in.readInt();
+        this.queryGroupHeapSize = in.readInt();
+    }
+
+    /**
+     * Constructor of QueryGrouperHealthStats
+     *
+     * @param queryGroupCount Number of groups in the grouper
+     * @param queryGroupHeapSize Heap size of the grouper
+     */
+    public QueryGrouperHealthStats(final int queryGroupCount, final int queryGroupHeapSize) {
+        this.queryGroupCount = queryGroupCount;
+        this.queryGroupHeapSize = queryGroupHeapSize;
+    }
+
+    /**
+     * Write QueryGrouperHealthStats Object to output stream
+     * @param out streamOutput
+     * @throws IOException IOException
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeInt(queryGroupCount);
+        out.writeInt(queryGroupHeapSize);
+    }
+
+    /**
+     * Write QueryGrouperHealthStats object to XContent
+     *
+     * @param builder XContentBuilder
+     * @param params Parameters
+     * @return XContentBuilder
+     * @throws IOException IOException
+     */
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field(QUERY_GROUP_COUNT_TOTAL, queryGroupCount);
+        builder.field(QUERY_GROUP_COUNT_MAX_HEAP, queryGroupHeapSize);
+        return builder;
+    }
+
+    /**
+     * Gets the number of query groups.
+     *
+     * @return the query group count
+     */
+    public int getQueryGroupCount() {
+        return queryGroupCount;
+    }
+
+    /**
+     * Gets the query group heap size.
+     *
+     * @return the query group heap size
+     */
+    public int getQueryGroupHeapSize() {
+        return queryGroupHeapSize;
+    }
+}