Top n queries historical queries from local index and time range

src/main/java/org/opensearch/plugin/insights/QueryInsightsPlugin.java

@@ -79,7 +79,8 @@ public Collection<Object> createComponents(
             clusterService.getClusterSettings(),
             threadPool,
             client,
-            metricsRegistry
+            metricsRegistry,
+            xContentRegistry
         );
         return List.of(queryInsightsService, new QueryInsightsListener(clusterService, queryInsightsService, false));
     }

src/main/java/org/opensearch/plugin/insights/core/reader/LocalIndexReader.java

@@ -0,0 +1,130 @@
+/*
+ * 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.core.reader;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.joda.time.DateTime;
+import org.joda.time.DateTimeZone;
+import org.joda.time.format.DateTimeFormatter;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.client.Client;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.index.IndexNotFoundException;
+import org.opensearch.index.query.MatchQueryBuilder;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.index.query.RangeQueryBuilder;
+import org.opensearch.plugin.insights.rules.model.SearchQueryRecord;
+import org.opensearch.search.SearchHit;
+import org.opensearch.search.builder.SearchSourceBuilder;
+
+/**
+ * Local index reader for reading query insights data from local OpenSearch indices.
+ */
+public final class LocalIndexReader implements QueryInsightsReader {
+    /**
+     * Logger of the local index reader
+     */
+    private final Logger logger = LogManager.getLogger();
+    private final Client client;
+    private DateTimeFormatter indexPattern;
+    private final NamedXContentRegistry namedXContentRegistry;
+
+    /**
+     * Constructor of LocalIndexReader
+     *
+     * @param client OS client
+     * @param indexPattern the pattern of index to read from
+     * @param namedXContentRegistry for parsing purposes
+     */
+    public LocalIndexReader(final Client client, final DateTimeFormatter indexPattern, final NamedXContentRegistry namedXContentRegistry) {
+        this.indexPattern = indexPattern;
+        this.client = client;
+        this.namedXContentRegistry = namedXContentRegistry;
+    }
+
+    /**
+     * Getter of indexPattern
+     *
+     * @return indexPattern
+     */
+    public DateTimeFormatter getIndexPattern() {
+        return indexPattern;
+    }
+
+    /**
+     * Setter of indexPattern
+     *
+     * @param indexPattern index pattern
+     * @return the current LocalIndexReader
+     */
+    public LocalIndexReader setIndexPattern(DateTimeFormatter indexPattern) {
+        this.indexPattern = indexPattern;
+        return this;
+    }
+
+    /**
+     * Export a list of SearchQueryRecord from local index
+     *
+     * @param from start timestamp
+     * @param to end timestamp
+     * @return list of SearchQueryRecords whose timestamps fall between from and to
+     */
+    @Override
+    public List<SearchQueryRecord> read(final String from, final String to) {
+        List<SearchQueryRecord> records = new ArrayList<>();
+        if (from == null || to == null) {
+            return records;
+        }
+        final DateTime start = DateTime.parse(from);
+        DateTime end = DateTime.parse(to);
+        if (end.compareTo(DateTime.now(DateTimeZone.UTC)) > 0) {
+            end = DateTime.now(DateTimeZone.UTC);
+        }
+        DateTime curr = start;
+        while (curr.compareTo(end.plusDays(1).withTimeAtStartOfDay()) < 0) {
+            String index = getDateTimeFromFormat(curr);
+            SearchRequest searchRequest = new SearchRequest(index);
+            SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
+            MatchQueryBuilder excludeQuery = QueryBuilders.matchQuery("indices", "top_queries*");
+            RangeQueryBuilder rangeQuery = QueryBuilders.rangeQuery("timestamp").from(start.getMillis()).to(end.getMillis());
+            QueryBuilder query = QueryBuilders.boolQuery().must(rangeQuery).mustNot(excludeQuery);
+            searchSourceBuilder.query(query);
+            searchRequest.source(searchSourceBuilder);
+            try {
+                SearchResponse searchResponse = client.search(searchRequest).actionGet();
+                for (SearchHit hit : searchResponse.getHits()) {
+                    SearchQueryRecord record = SearchQueryRecord.getRecord(hit, namedXContentRegistry);
+                    records.add(record);
+                }
+            } catch (IndexNotFoundException ignored) {} catch (Exception e) {
+                logger.error("Unable to parse search hit: ", e);
+            }
+            curr = curr.plusDays(1);
+
+        }
+        return records;
+    }
+
+    /**
+     * Close the reader sink
+     */
+    @Override
+    public void close() {
+        logger.debug("Closing the LocalIndexReader..");
+    }
+
+    private String getDateTimeFromFormat(DateTime current) {
+        return indexPattern.print(current);
+    }
+}

src/main/java/org/opensearch/plugin/insights/core/reader/QueryInsightsReader.java

@@ -0,0 +1,27 @@
+/*
+ * 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.core.reader;
+
+import java.io.Closeable;
+import java.util.List;
+import org.opensearch.plugin.insights.rules.model.SearchQueryRecord;
+
+/**
+ * Base interface for Query Insights readers
+ */
+public interface QueryInsightsReader extends Closeable {
+    /**
+     * Reader a list of SearchQueryRecord
+     *
+     * @param from string
+     * @param to string
+     * @return List of SearchQueryRecord
+     */
+    List<SearchQueryRecord> read(final String from, final String to);
+}

src/main/java/org/opensearch/plugin/insights/core/reader/QueryInsightsReaderFactory.java

@@ -0,0 +1,118 @@
+/*
+ * 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.core.reader;
+
+import static org.opensearch.plugin.insights.settings.QueryInsightsSettings.DEFAULT_TOP_N_QUERIES_INDEX_PATTERN;
+import static org.opensearch.plugin.insights.settings.QueryInsightsSettings.EXPORT_INDEX;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Set;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.joda.time.format.DateTimeFormat;
+import org.opensearch.client.Client;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+
+/**
+ * Factory class for validating and creating Readers based on provided settings
+ */
+public class QueryInsightsReaderFactory {
+    /**
+     * Logger of the query insights Reader factory
+     */
+    private final Logger logger = LogManager.getLogger();
+    final private Client client;
+    final private Set<QueryInsightsReader> Readers;
+
+    /**
+     * Constructor of QueryInsightsReaderFactory
+     *
+     * @param client OS client
+     */
+    public QueryInsightsReaderFactory(final Client client) {
+        this.client = client;
+        this.Readers = new HashSet<>();
+    }
+
+    /**
+     * Validate Reader sink config
+     *
+     * @param settings Reader sink config {@link Settings}
+     * @throws IllegalArgumentException if provided Reader sink config settings are invalid
+     */
+    public void validateReaderConfig(final Settings settings) throws IllegalArgumentException {
+        final String indexPattern = settings.get(EXPORT_INDEX, DEFAULT_TOP_N_QUERIES_INDEX_PATTERN);
+        if (indexPattern.isEmpty()) {
+            throw new IllegalArgumentException("Empty index pattern configured for the Reader");
+        }
+        try {
+            DateTimeFormat.forPattern(indexPattern);
+        } catch (Exception e) {
+            throw new IllegalArgumentException(
+                String.format(Locale.ROOT, "Invalid index pattern [%s] configured for the Reader", indexPattern)
+            );
+        }
+    }
+
+    /**
+     * Create a Reader based on provided parameters
+     *
+     * @param indexPattern the index pattern if creating an index Reader
+     * @param namedXContentRegistry for parsing purposes
+     * @return QueryInsightsReader the created Reader
+     */
+    public QueryInsightsReader createReader(String indexPattern, NamedXContentRegistry namedXContentRegistry) {
+        QueryInsightsReader Reader = new LocalIndexReader(client, DateTimeFormat.forPattern(indexPattern), namedXContentRegistry);
+        this.Readers.add(Reader);
+        return Reader;
+    }
+
+    /**
+     * Update a Reader based on provided parameters
+     *
+     * @param Reader The Reader to update
+     * @param indexPattern the index pattern if creating an index Reader
+     * @return QueryInsightsReader the updated Reader sink
+     */
+    public QueryInsightsReader updateReader(QueryInsightsReader Reader, String indexPattern) {
+        if (Reader.getClass() == LocalIndexReader.class) {
+            ((LocalIndexReader) Reader).setIndexPattern(DateTimeFormat.forPattern(indexPattern));
+        }
+        return Reader;
+    }
+
+    /**
+     * Close a Reader
+     *
+     * @param Reader the Reader to close
+     */
+    public void closeReader(QueryInsightsReader Reader) throws IOException {
+        if (Reader != null) {
+            Reader.close();
+            this.Readers.remove(Reader);
+        }
+    }
+
+    /**
+     * Close all Readers
+     *
+     */
+    public void closeAllReaders() {
+        for (QueryInsightsReader Reader : Readers) {
+            try {
+                closeReader(Reader);
+            } catch (IOException e) {
+                logger.error("Fail to close query insights Reader, error: ", e);
+            }
+        }
+    }
+}

src/main/java/org/opensearch/plugin/insights/core/reader/package-info.java

@@ -0,0 +1,12 @@
+/*
+ * 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.
+ */
+
+/**
+ * Query Insights reader
+ */
+package org.opensearch.plugin.insights.core.reader;