Added tests and refactoring

Signed-off-by: Sarthak Aggarwal <sarthagg@amazon.com>

server/build.gradle

@@ -146,7 +146,6 @@ dependencies {
   // jna
   api "net.java.dev.jna:jna:${versions.jna}"
 
-  api "com.github.luben:zstd-jni:1.5.5-1"
   // protobuf
   api "com.google.protobuf:protobuf-java:${versions.protobuf}"
   api "jakarta.annotation:jakarta.annotation-api:${versions.jakarta_annotation}"

server/src/main/java/org/opensearch/index/codec/customcodecs/Lucene95CustomCodec.java

@@ -15,7 +15,7 @@
 import org.opensearch.index.codec.PerFieldMappingPostingFormatCodec;
 import org.opensearch.index.mapper.MapperService;
 
-abstract class Lucene95CustomCodec extends FilterCodec {
+public abstract class Lucene95CustomCodec extends FilterCodec {
     public static final int DEFAULT_COMPRESSION_LEVEL = 6;
 
     /** Each mode represents a compression algorithm. */

server/src/main/java/org/opensearch/index/codec/customcodecs/Lucene95CustomStoredFieldsFormat.java

@@ -96,7 +96,7 @@ public StoredFieldsWriter fieldsWriter(Directory directory, SegmentInfo si, IOCo
         return impl(mode).fieldsWriter(directory, si, context);
     }
 
-    private StoredFieldsFormat impl(Lucene95CustomCodec.Mode mode) {
+    StoredFieldsFormat impl(Lucene95CustomCodec.Mode mode) {
         switch (mode) {
             case ZSTD:
                 return new Lucene90CompressingStoredFieldsFormat(
@@ -118,4 +118,8 @@ private StoredFieldsFormat impl(Lucene95CustomCodec.Mode mode) {
                 throw new AssertionError();
         }
     }
+
+    Lucene95CustomCodec.Mode getMode() {
+        return mode;
+    }
 }

server/src/test/java/org/opensearch/index/codec/CodecTests.java

@@ -47,6 +47,8 @@
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.IndexAnalyzers;
+import org.opensearch.index.codec.customcodecs.Lucene95CustomCodec;
+import org.opensearch.index.codec.customcodecs.Lucene95CustomStoredFieldsFormat;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.indices.mapper.MapperRegistry;
@@ -63,40 +65,75 @@
 public class CodecTests extends OpenSearchTestCase {
 
     public void testResolveDefaultCodecs() throws Exception {
-        CodecService codecService = createCodecService();
+        CodecService codecService = createCodecService(false);
         assertThat(codecService.codec("default"), instanceOf(PerFieldMappingPostingFormatCodec.class));
         assertThat(codecService.codec("default"), instanceOf(Lucene95Codec.class));
     }
 
     public void testDefault() throws Exception {
-        Codec codec = createCodecService().codec("default");
+        Codec codec = createCodecService(false).codec("default");
         assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_SPEED, codec);
     }
 
     public void testBestCompression() throws Exception {
-        Codec codec = createCodecService().codec("best_compression");
+        Codec codec = createCodecService(false).codec("best_compression");
         assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_COMPRESSION, codec);
     }
 
+    public void testZstd() throws Exception {
+        Codec codec = createCodecService(false).codec("zstd");
+        assertStoredFieldsCompressionEquals(Lucene95CustomCodec.Mode.ZSTD, codec);
+    }
+
+    public void testZstdNoDict() throws Exception {
+        Codec codec = createCodecService(false).codec("zstd_no_dict");
+        assertStoredFieldsCompressionEquals(Lucene95CustomCodec.Mode.ZSTD_NO_DICT, codec);
+    }
+
+    public void testDefaultMapperServiceNull() throws Exception {
+        Codec codec = createCodecService(true).codec("default");
+        assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_SPEED, codec);
+    }
+
+    public void testBestCompressionMapperServiceNull() throws Exception {
+        Codec codec = createCodecService(true).codec("best_compression");
+        assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_COMPRESSION, codec);
+    }
+
+    public void testZstdMapperServiceNull() throws Exception {
+        Codec codec = createCodecService(true).codec("zstd");
+        assertStoredFieldsCompressionEquals(Lucene95CustomCodec.Mode.ZSTD, codec);
+    }
+
+    public void testZstdNoDictMapperServiceNull() throws Exception {
+        Codec codec = createCodecService(true).codec("zstd_no_dict");
+        assertStoredFieldsCompressionEquals(Lucene95CustomCodec.Mode.ZSTD_NO_DICT, codec);
+    }
+
+    public void testExceptionCodecNull() {
+        assertThrows(IllegalArgumentException.class, () -> createCodecService(true).codec(null));
+    }
+
     // write some docs with it, inspect .si to see this was the used compression
     private void assertStoredFieldsCompressionEquals(Lucene95Codec.Mode expected, Codec actual) throws Exception {
-        Directory dir = newDirectory();
-        IndexWriterConfig iwc = newIndexWriterConfig(null);
-        iwc.setCodec(actual);
-        IndexWriter iw = new IndexWriter(dir, iwc);
-        iw.addDocument(new Document());
-        iw.commit();
-        iw.close();
-        DirectoryReader ir = DirectoryReader.open(dir);
-        SegmentReader sr = (SegmentReader) ir.leaves().get(0).reader();
+        SegmentReader sr = getSegmentReader(actual);
         String v = sr.getSegmentInfo().info.getAttribute(Lucene90StoredFieldsFormat.MODE_KEY);
         assertNotNull(v);
         assertEquals(expected, Lucene95Codec.Mode.valueOf(v));
-        ir.close();
-        dir.close();
     }
 
-    private CodecService createCodecService() throws IOException {
+    private void assertStoredFieldsCompressionEquals(Lucene95CustomCodec.Mode expected, Codec actual) throws Exception {
+        SegmentReader sr = getSegmentReader(actual);
+        String v = sr.getSegmentInfo().info.getAttribute(Lucene95CustomStoredFieldsFormat.MODE_KEY);
+        assertNotNull(v);
+        assertEquals(expected, Lucene95CustomCodec.Mode.valueOf(v));
+    }
+
+    private CodecService createCodecService(boolean isMapperServiceNull) throws IOException {
+
+        if (isMapperServiceNull) {
+            return new CodecService(null, LogManager.getLogger("test"));
+        }
         Settings nodeSettings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir()).build();
         IndexSettings settings = IndexSettingsModule.newIndexSettings("_na", nodeSettings);
         SimilarityService similarityService = new SimilarityService(settings, null, Collections.emptyMap());
@@ -115,4 +152,18 @@ private CodecService createCodecService() throws IOException {
         return new CodecService(service, LogManager.getLogger("test"));
     }
 
+    private SegmentReader getSegmentReader(Codec actual) throws IOException {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig(null);
+        iwc.setCodec(actual);
+        IndexWriter iw = new IndexWriter(dir, iwc);
+        iw.addDocument(new Document());
+        iw.commit();
+        iw.close();
+        DirectoryReader ir = DirectoryReader.open(dir);
+        SegmentReader sr = (SegmentReader) ir.leaves().get(0).reader();
+        ir.close();
+        dir.close();
+        return sr;
+    }
 }

server/src/test/java/org/opensearch/index/codec/customcodecs/Lucene95CustomStoredFieldsFormatTests.java

@@ -0,0 +1,25 @@
+/*
+ * 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.index.codec.customcodecs;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+public class Lucene95CustomStoredFieldsFormatTests extends OpenSearchTestCase {
+
+    public void testDefaultLucene95CustomCodecMode() {
+        Lucene95CustomStoredFieldsFormat lucene95CustomStoredFieldsFormat = new Lucene95CustomStoredFieldsFormat();
+        assertEquals(Lucene95CustomCodec.Mode.ZSTD, lucene95CustomStoredFieldsFormat.getMode());
+    }
+
+    public void testZstdNoDictLucene95CustomCodecMode() {
+        Lucene95CustomStoredFieldsFormat lucene95CustomStoredFieldsFormat = new Lucene95CustomStoredFieldsFormat(Lucene95CustomCodec.Mode.ZSTD_NO_DICT);
+        assertEquals(Lucene95CustomCodec.Mode.ZSTD_NO_DICT, lucene95CustomStoredFieldsFormat.getMode());
+    }
+
+}