S3BlobContainer.java

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 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
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package org.elasticsearch.repositories.s3;

import com.amazonaws.AmazonClientException;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.model.AmazonS3Exception;
import com.amazonaws.services.s3.model.CopyObjectRequest;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.services.s3.model.S3ObjectSummary;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.blobstore.BlobMetaData;
import org.elasticsearch.common.blobstore.BlobPath;
import org.elasticsearch.common.blobstore.BlobStoreException;
import org.elasticsearch.common.blobstore.support.AbstractBlobContainer;
import org.elasticsearch.common.blobstore.support.PlainBlobMetaData;
import org.elasticsearch.common.collect.MapBuilder;
import org.elasticsearch.common.io.Streams;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.FileAlreadyExistsException;
import java.nio.file.NoSuchFileException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Map;

class S3BlobContainer extends AbstractBlobContainer {

    protected final S3BlobStore blobStore;

    protected final String keyPath;

    S3BlobContainer(BlobPath path, S3BlobStore blobStore) {
        super(path);
        this.blobStore = blobStore;
        this.keyPath = path.buildAsString();
    }

    @Override
    public boolean blobExists(String blobName) {
        try {
            return SocketAccess.doPrivileged(() -> {
                blobStore.client().getObjectMetadata(blobStore.bucket(), buildKey(blobName));
                return true;
            });
        } catch (AmazonS3Exception e) {
            return false;
        } catch (Exception e) {
            throw new BlobStoreException("failed to check if blob exists", e);
        }
    }

    @Override
    public InputStream readBlob(String blobName) throws IOException {
        try {
            S3Object s3Object = SocketAccess.doPrivileged(() -> blobStore.client().getObject(blobStore.bucket(), buildKey(blobName)));
            return s3Object.getObjectContent();
        } catch (AmazonClientException e) {
            if (e instanceof AmazonS3Exception) {
                if (404 == ((AmazonS3Exception) e).getStatusCode()) {
                    throw new NoSuchFileException("Blob object [" + blobName + "] not found: " + e.getMessage());
                }
            }
            throw e;
        }
    }

    @Override
    public void writeBlob(String blobName, InputStream inputStream, long blobSize) throws IOException {
        if (blobExists(blobName)) {
            throw new FileAlreadyExistsException("blob [" + blobName + "] already exists, cannot overwrite");
        }
        try (OutputStream stream = createOutput(blobName)) {
            SocketAccess.doPrivilegedIOException(() -> Streams.copy(inputStream, stream));
        }
    }

    @Override
    public void deleteBlob(String blobName) throws IOException {
        if (!blobExists(blobName)) {
            throw new NoSuchFileException("Blob [" + blobName + "] does not exist");
        }

        try {
            SocketAccess.doPrivilegedVoid(() -> blobStore.client().deleteObject(blobStore.bucket(), buildKey(blobName)));
        } catch (AmazonClientException e) {
            throw new IOException("Exception when deleting blob [" + blobName + "]", e);
        }
    }

    private OutputStream createOutput(final String blobName) throws IOException {
        // UploadS3OutputStream does buffering & retry logic internally
        return new DefaultS3OutputStream(blobStore, blobStore.bucket(), buildKey(blobName),
            blobStore.bufferSizeInBytes(), blobStore.serverSideEncryption());
    }

    @Override
    public Map<String, BlobMetaData> listBlobsByPrefix(@Nullable String blobNamePrefix) throws IOException {
        return AccessController.doPrivileged((PrivilegedAction<Map<String, BlobMetaData>>) () -> {
            MapBuilder<String, BlobMetaData> blobsBuilder = MapBuilder.newMapBuilder();
            AmazonS3 client = blobStore.client();
            SocketAccess.doPrivilegedVoid(() -> {
                ObjectListing prevListing = null;
                while (true) {
                    ObjectListing list;
                    if (prevListing != null) {
                        list = client.listNextBatchOfObjects(prevListing);
                    } else {
                        if (blobNamePrefix != null) {
                            list = client.listObjects(blobStore.bucket(), buildKey(blobNamePrefix));
                        } else {
                            list = client.listObjects(blobStore.bucket(), keyPath);
                        }
                    }
                    for (S3ObjectSummary summary : list.getObjectSummaries()) {
                        String name = summary.getKey().substring(keyPath.length());
                        blobsBuilder.put(name, new PlainBlobMetaData(name, summary.getSize()));
                    }
                    if (list.isTruncated()) {
                        prevListing = list;
                    } else {
                        break;
                    }
                }
            });
            return blobsBuilder.immutableMap();
        });
    }

    @Override
    public void move(String sourceBlobName, String targetBlobName) throws IOException {
        try {
            CopyObjectRequest request = new CopyObjectRequest(blobStore.bucket(), buildKey(sourceBlobName),
                blobStore.bucket(), buildKey(targetBlobName));

            if (blobStore.serverSideEncryption()) {
                ObjectMetadata objectMetadata = new ObjectMetadata();
                objectMetadata.setSSEAlgorithm(ObjectMetadata.AES_256_SERVER_SIDE_ENCRYPTION);
                request.setNewObjectMetadata(objectMetadata);
            }

            SocketAccess.doPrivilegedVoid(() -> {
                blobStore.client().copyObject(request);
                blobStore.client().deleteObject(blobStore.bucket(), buildKey(sourceBlobName));
            });

        } catch (AmazonS3Exception e) {
            throw new IOException(e);
        }
    }

    @Override
    public Map<String, BlobMetaData> listBlobs() throws IOException {
        return listBlobsByPrefix(null);
    }

    protected String buildKey(String blobName) {
        return keyPath + blobName;
    }
}