Create serde utility for Writable classes

Signed-off-by: Sooraj Sinha <[email protected]>

server/src/main/java/org/opensearch/repositories/blobstore/ChecksumWritableBlobStoreFormat.java

@@ -0,0 +1,114 @@
+/*
+ * 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.repositories.blobstore;
+
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.index.IndexFormatTooNewException;
+import org.apache.lucene.index.IndexFormatTooOldException;
+import org.apache.lucene.store.ByteBuffersDataInput;
+import org.apache.lucene.store.ByteBuffersIndexInput;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.Version;
+import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.common.lucene.store.IndexOutputOutputStream;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+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.compress.Compressor;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.compress.NotXContentException;
+import org.opensearch.gateway.CorruptStateException;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Arrays;
+
+/**
+ * Checksum File format used to serialize/deserialize {@link Writeable} objects
+ *
+ * @opensearch.internal
+ */
+public class ChecksumWritableBlobStoreFormat<T extends Writeable> {
+
+    public static final int VERSION = 1;
+
+    private static final int BUFFER_SIZE = 4096;
+
+    private final String codec;
+    private final CheckedFunction<StreamInput, T, IOException> reader;
+
+    public ChecksumWritableBlobStoreFormat(String codec, CheckedFunction<StreamInput, T, IOException> reader) {
+        this.codec = codec;
+        this.reader = reader;
+    }
+
+    public BytesReference serialize(final T obj, final String blobName, final Compressor compressor) throws IOException {
+        try (BytesStreamOutput outputStream = new BytesStreamOutput()) {
+            try (
+                OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput(
+                    "ChecksumBlobStoreFormat.writeBlob(blob=\"" + blobName + "\")",
+                    blobName,
+                    outputStream,
+                    BUFFER_SIZE
+                )
+            ) {
+                CodecUtil.writeHeader(indexOutput, codec, VERSION);
+
+                try (OutputStream indexOutputOutputStream = new IndexOutputOutputStream(indexOutput) {
+                    @Override
+                    public void close() throws IOException {
+                        // this is important since some of the XContentBuilders write bytes on close.
+                        // in order to write the footer we need to prevent closing the actual index input.
+                    }
+                }; StreamOutput stream = new OutputStreamStreamOutput(compressor.threadLocalOutputStream(indexOutputOutputStream));) {
+                    // TODO The stream version should be configurable
+                    stream.setVersion(Version.CURRENT);
+                    obj.writeTo(stream);
+                }
+                CodecUtil.writeFooter(indexOutput);
+            }
+            return outputStream.bytes();
+        }
+    }
+
+    public T deserialize(String blobName, CheckedFunction<StreamInput, T, IOException> reader, BytesReference bytes) throws IOException {
+        final String resourceDesc = "ChecksumBlobStoreFormat.readBlob(blob=\"" + blobName + "\")";
+        try {
+            final IndexInput indexInput = bytes.length() > 0
+                ? new ByteBuffersIndexInput(new ByteBuffersDataInput(Arrays.asList(BytesReference.toByteBuffers(bytes))), resourceDesc)
+                : new ByteArrayIndexInput(resourceDesc, BytesRef.EMPTY_BYTES);
+            CodecUtil.checksumEntireFile(indexInput);
+            CodecUtil.checkHeader(indexInput, codec, VERSION, VERSION);
+            long filePointer = indexInput.getFilePointer();
+            long contentSize = indexInput.length() - CodecUtil.footerLength() - filePointer;
+            BytesReference bytesReference = bytes.slice((int) filePointer, (int) contentSize);
+            Compressor compressor;
+            try {
+                compressor = CompressorRegistry.compressor(bytesReference);
+            } catch (NotXContentException e) {
+                compressor = CompressorRegistry.none();
+            }
+            try (StreamInput in = new InputStreamStreamInput(compressor.threadLocalInputStream(bytesReference.streamInput()))) {
+                return reader.apply(in);
+            }
+        } catch (CorruptIndexException | IndexFormatTooOldException | IndexFormatTooNewException ex) {
+            // we trick this into a dedicated exception with the original stacktrace
+            throw new CorruptStateException(ex);
+        }
+    }
+
+}

server/src/test/java/org/opensearch/repositories/blobstore/ChecksumWritableBlobStoreFormatTests.java

@@ -0,0 +1,54 @@
+/*
+ * 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.repositories.blobstore;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+import static org.hamcrest.Matchers.is;
+
+/**
+ * Tests for {@link ChecksumWritableBlobStoreFormat}
+ */
+public class ChecksumWritableBlobStoreFormatTests extends OpenSearchTestCase {
+    private static final String TEST_BLOB_FILE_NAME = "test-blob-name";
+    private static final long VERSION = 5L;
+
+    private final ChecksumWritableBlobStoreFormat<IndexMetadata> clusterBlocksFormat = new ChecksumWritableBlobStoreFormat<>(
+        "index-metadata",
+        IndexMetadata::readFrom
+    );
+
+    public void testSerDe() throws IOException {
+        IndexMetadata indexMetadata = getIndexMetadata();
+        BytesReference bytesReference = clusterBlocksFormat.serialize(indexMetadata, TEST_BLOB_FILE_NAME, CompressorRegistry.none());
+        IndexMetadata readIndexMetadata = clusterBlocksFormat.deserialize(TEST_BLOB_FILE_NAME, IndexMetadata::readFrom, bytesReference);
+        assertThat(readIndexMetadata, is(indexMetadata));
+    }
+
+    private IndexMetadata getIndexMetadata() {
+        final Index index = new Index("test-index", "index-uuid");
+        final Settings idxSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_INDEX_UUID, index.getUUID())
+            .build();
+        return new IndexMetadata.Builder(index.getName()).settings(idxSettings)
+            .version(VERSION)
+            .numberOfShards(1)
+            .numberOfReplicas(0)
+            .build();
+    }
+}