alluxio.underfs.cos.COSOutputStream.java Source code

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Here is the source code for alluxio.underfs.cos.COSOutputStream.java

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/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.underfs.cos;

import alluxio.util.CommonUtils;
import alluxio.util.io.PathUtils;

import com.google.common.base.Preconditions;
import com.qcloud.cos.COSClient;
import com.qcloud.cos.model.ObjectMetadata;
import com.qcloud.cos.exception.CosClientException;

import org.apache.commons.codec.binary.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.security.DigestOutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.annotation.concurrent.NotThreadSafe;

/**
 * A stream for writing a file into COS. The data will be persisted to a temporary directory on the
 * local disk and copied as a complete file when the {@link #close()} method is called.
 */
@NotThreadSafe
public final class COSOutputStream extends OutputStream {
    private static final Logger LOG = LoggerFactory.getLogger(COSOutputStream.class);

    /** Bucket name of the Alluxio COS bucket. */
    private final String mBucketName;
    /** Key of the file when it is uploaded to COS. */
    private final String mKey;
    /** The local file that will be uploaded when the stream is closed. */
    private final File mFile;
    /** The cos client for COS operations. */
    private final COSClient mCosClient;

    /** The outputstream to a local file where the file will be buffered until closed. */
    private OutputStream mLocalOutputStream;
    /** The MD5 hash of the file. */
    private MessageDigest mHash;

    /** Flag to indicate this stream has been closed, to ensure close is only done once. */
    private AtomicBoolean mClosed = new AtomicBoolean(false);

    /**
     * Creates a name instance of {@link COSOutputStream}.
     *
     * @param bucketName the name of the bucket
     * @param key the key of the file
     * @param client the client for COS
     */
    public COSOutputStream(String bucketName, String key, COSClient client) throws IOException {
        Preconditions.checkArgument(bucketName != null && !bucketName.isEmpty(),
                "Bucket name must not be null or empty.");
        Preconditions.checkArgument(key != null && !key.isEmpty(), "COS path must not be null or empty.");
        Preconditions.checkArgument(client != null, "COSClient must not be null.");
        mBucketName = bucketName;
        mKey = key;
        mCosClient = client;

        mFile = new File(PathUtils.concatPath(CommonUtils.getTmpDir(), UUID.randomUUID()));

        try {
            mHash = MessageDigest.getInstance("MD5");
            mLocalOutputStream = new BufferedOutputStream(
                    new DigestOutputStream(new FileOutputStream(mFile), mHash));
        } catch (NoSuchAlgorithmException e) {
            LOG.warn("Algorithm not available for MD5 hash.", e);
            mHash = null;
            mLocalOutputStream = new BufferedOutputStream(new FileOutputStream(mFile));
        }
    }

    /**
     * Writes the given bytes to this output stream. Before close, the bytes are all written to local
     * file.
     *
     * @param b the bytes to write
     */
    @Override
    public void write(int b) throws IOException {
        mLocalOutputStream.write(b);
    }

    /**
     * Writes the given byte array to this output stream. Before close, the bytes are all written to
     * local file.
     *
     * @param b the byte array
     */
    @Override
    public void write(byte[] b) throws IOException {
        mLocalOutputStream.write(b, 0, b.length);
    }

    /**
     * Writes the given number of bytes from the given byte array starting at the given offset to this
     * output stream. Before close, the bytes are all written to local file.
     *
     * @param b the byte array
     * @param off the start offset in the data
     * @param len the number of bytes to write
     */
    @Override
    public void write(byte[] b, int off, int len) throws IOException {
        mLocalOutputStream.write(b, off, len);
    }

    /**
     * Flushes this output stream and forces any buffered output bytes to be written out. Before
     * close, the data are flushed to local file.
     */
    @Override
    public void flush() throws IOException {
        mLocalOutputStream.flush();
    }

    /**
     * Closes this output stream. When an output stream is closed, the local temporary file is
     * uploaded to COS Service. Once the file is uploaded, the temporary file is deleted.
     */
    @Override
    public void close() throws IOException {
        if (mClosed.getAndSet(true)) {
            return;
        }
        mLocalOutputStream.close();
        try (BufferedInputStream in = new BufferedInputStream(new FileInputStream(mFile))) {
            ObjectMetadata meta = new ObjectMetadata();
            meta.setContentLength(mFile.length());
            if (mHash != null) {
                byte[] hashBytes = mHash.digest();
                meta.setContentMD5(new String(Base64.encodeBase64(hashBytes)));
            }
            mCosClient.putObject(mBucketName, mKey, in, meta);
            mFile.delete();
        } catch (CosClientException e) {
            LOG.error("Failed to upload {}. Temporary file @ {}", mKey, mFile.getPath());
            throw new IOException(e);
        }
        return;
    }
}