Add support for deep copying SearchRequest (opensearch-project#12295)

Signed-off-by: Chenyang Ji <[email protected]>

CHANGELOG.md

@@ -34,6 +34,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - [Remote Store] Add settings for remote path type and hash algorithm ([#13225](https://github.com/opensearch-project/OpenSearch/pull/13225))
 - [Remote Store] Upload remote paths during remote enabled index creation ([#13386](https://github.com/opensearch-project/OpenSearch/pull/13386))
 - [Search Pipeline] Handle default pipeline for multiple indices ([#13276](https://github.com/opensearch-project/OpenSearch/pull/13276))
+- Add support for deep copying SearchRequest ([#12295](https://github.com/opensearch-project/OpenSearch/pull/12295))
 
 ### Dependencies
 - Bump `org.apache.commons:commons-configuration2` from 2.10.0 to 2.10.1 ([#12896](https://github.com/opensearch-project/OpenSearch/pull/12896))

server/src/main/java/org/opensearch/action/search/SearchRequest.java

@@ -40,6 +40,7 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.core.common.Strings;
 import org.opensearch.core.common.io.stream.StreamInput;
@@ -161,6 +162,18 @@ public SearchRequest(String[] indices, SearchSourceBuilder source) {
         this.source = source;
     }
 
+    /**
+     * Deep clone a SearchRequest
+     *
+     * @return a copy of the current SearchRequest
+     */
+    public SearchRequest deepCopy() throws IOException {
+        BytesStreamOutput out = new BytesStreamOutput();
+        this.writeTo(out);
+        StreamInput in = out.bytes().streamInput();
+        return new SearchRequest(in);
+    }
+
     /**
      * Creates a new sub-search request starting from the original search request that is provided.
      * For internal use only, allows to fork a search request into multiple search requests that will be executed independently.

server/src/test/java/org/opensearch/action/search/SearchRequestTests.java

@@ -46,6 +46,7 @@
 import org.opensearch.search.Scroll;
 import org.opensearch.search.builder.PointInTimeBuilder;
 import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.search.fetch.subphase.FetchSourceContext;
 import org.opensearch.search.rescore.QueryRescorerBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
@@ -76,6 +77,35 @@ protected SearchRequest createSearchRequest() throws IOException {
         );
     }
 
+    public void testClone() throws IOException {
+        SearchRequest searchRequest = new SearchRequest();
+        SearchRequest clonedRequest = searchRequest.deepCopy();
+        assertEquals(searchRequest.hashCode(), clonedRequest.hashCode());
+        assertNotSame(searchRequest, clonedRequest);
+
+        String[] includes = new String[] { "field1.*" };
+        String[] excludes = new String[] { "field2.*" };
+        FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes);
+        SearchSourceBuilder source = new SearchSourceBuilder().fetchSource(fetchSourceContext);
+        SearchRequest complexSearchRequest = createSearchRequest().source(source);
+        complexSearchRequest.requestCache(false);
+        complexSearchRequest.scroll(new TimeValue(1000));
+        SearchRequest clonedComplexRequest = complexSearchRequest.deepCopy();
+        assertEquals(complexSearchRequest.hashCode(), clonedComplexRequest.hashCode());
+        assertNotSame(complexSearchRequest, clonedComplexRequest);
+        assertEquals(fetchSourceContext, clonedComplexRequest.source().fetchSource());
+        assertNotSame(fetchSourceContext, clonedComplexRequest.source().fetchSource());
+        // Change the value of the original includes array and excludes array
+        includes[0] = "new_field1.*";
+        excludes[0] = "new_field2.*";
+        // Values in the original fetchSource object should be updated
+        assertEquals("new_field1.*", complexSearchRequest.source().fetchSource().includes()[0]);
+        assertEquals("new_field2.*", complexSearchRequest.source().fetchSource().excludes()[0]);
+        // Values in the cloned fetchSource object should not be updated
+        assertEquals("field1.*", clonedComplexRequest.source().fetchSource().includes()[0]);
+        assertEquals("field2.*", clonedComplexRequest.source().fetchSource().excludes()[0]);
+    }
+
     public void testWithLocalReduction() {
         expectThrows(NullPointerException.class, () -> SearchRequest.subSearchRequest(null, Strings.EMPTY_ARRAY, "", 0, randomBoolean()));
         SearchRequest request = new SearchRequest();