org.apache.hadoop.fs.s3a.S3AFileSystem.java Source code

Java tutorial

Introduction

Here is the source code for org.apache.hadoop.fs.s3a.S3AFileSystem.java

Source

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 */

package org.apache.hadoop.fs.s3a;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.ClientConfiguration;
import com.amazonaws.Protocol;
import com.amazonaws.auth.AWSCredentialsProviderChain;

import com.amazonaws.auth.InstanceProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.CannedAccessControlList;
import com.amazonaws.services.s3.model.DeleteObjectsRequest;
import com.amazonaws.services.s3.model.ListObjectsRequest;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.PutObjectRequest;
import com.amazonaws.services.s3.model.CopyObjectRequest;
import com.amazonaws.services.s3.model.S3ObjectSummary;
import com.amazonaws.services.s3.transfer.Copy;
import com.amazonaws.services.s3.transfer.TransferManager;
import com.amazonaws.services.s3.transfer.TransferManagerConfiguration;
import com.amazonaws.services.s3.transfer.Upload;
import com.amazonaws.event.ProgressListener;
import com.amazonaws.event.ProgressEvent;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocalFileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.util.Progressable;

import static org.apache.hadoop.fs.s3a.Constants.*;

public class S3AFileSystem extends FileSystem {
    private URI uri;
    private Path workingDir;
    private AmazonS3Client s3;
    private String bucket;
    private int maxKeys;
    private long partSize;
    private long partSizeThreshold;
    public static final Log LOG = LogFactory.getLog(S3AFileSystem.class);
    private CannedAccessControlList cannedACL;
    private String serverSideEncryptionAlgorithm;

    // The maximum number of entries that can be deleted in any call to s3
    private static final int MAX_ENTRIES_TO_DELETE = 1000;

    /** Called after a new FileSystem instance is constructed.
     * @param name a uri whose authority section names the host, port, etc.
     *   for this FileSystem
     * @param conf the configuration
     */
    public void initialize(URI name, Configuration conf) throws IOException {
        super.initialize(name, conf);

        uri = URI.create(name.getScheme() + "://" + name.getAuthority());
        workingDir = new Path("/user", System.getProperty("user.name")).makeQualified(this.uri,
                this.getWorkingDirectory());

        // Try to get our credentials or just connect anonymously
        String accessKey = conf.get(NEW_ACCESS_KEY, conf.get(OLD_ACCESS_KEY, null));
        String secretKey = conf.get(NEW_SECRET_KEY, conf.get(OLD_SECRET_KEY, null));

        String userInfo = name.getUserInfo();
        if (userInfo != null) {
            int index = userInfo.indexOf(':');
            if (index != -1) {
                accessKey = userInfo.substring(0, index);
                secretKey = userInfo.substring(index + 1);
            } else {
                accessKey = userInfo;
            }
        }

        AWSCredentialsProviderChain credentials = new AWSCredentialsProviderChain(
                new BasicAWSCredentialsProvider(accessKey, secretKey), new InstanceProfileCredentialsProvider(),
                new AnonymousAWSCredentialsProvider());

        bucket = name.getHost();

        ClientConfiguration awsConf = new ClientConfiguration();
        awsConf.setMaxConnections(conf.getInt(NEW_MAXIMUM_CONNECTIONS,
                conf.getInt(OLD_MAXIMUM_CONNECTIONS, DEFAULT_MAXIMUM_CONNECTIONS)));
        awsConf.setProtocol(conf.getBoolean(NEW_SECURE_CONNECTIONS,
                conf.getBoolean(OLD_SECURE_CONNECTIONS, DEFAULT_SECURE_CONNECTIONS)) ? Protocol.HTTPS
                        : Protocol.HTTP);
        awsConf.setMaxErrorRetry(
                conf.getInt(NEW_MAX_ERROR_RETRIES, conf.getInt(OLD_MAX_ERROR_RETRIES, DEFAULT_MAX_ERROR_RETRIES)));
        awsConf.setSocketTimeout(
                conf.getInt(NEW_SOCKET_TIMEOUT, conf.getInt(OLD_SOCKET_TIMEOUT, DEFAULT_SOCKET_TIMEOUT)));

        s3 = new AmazonS3Client(credentials, awsConf);

        maxKeys = conf.getInt(NEW_MAX_PAGING_KEYS, conf.getInt(OLD_MAX_PAGING_KEYS, DEFAULT_MAX_PAGING_KEYS));
        partSize = conf.getLong(NEW_MULTIPART_SIZE, conf.getLong(OLD_MULTIPART_SIZE, DEFAULT_MULTIPART_SIZE));
        partSizeThreshold = conf.getLong(NEW_MIN_MULTIPART_THRESHOLD,
                conf.getLong(OLD_MIN_MULTIPART_THRESHOLD, DEFAULT_MIN_MULTIPART_THRESHOLD));

        if (partSize < 5 * 1024 * 1024) {
            LOG.error(NEW_MULTIPART_SIZE + " must be at least 5 MB");
            partSize = 5 * 1024 * 1024;
        }

        if (partSizeThreshold < 5 * 1024 * 1024) {
            LOG.error(NEW_MIN_MULTIPART_THRESHOLD + " must be at least 5 MB");
            partSizeThreshold = 5 * 1024 * 1024;
        }

        String cannedACLName = conf.get(NEW_CANNED_ACL, conf.get(OLD_CANNED_ACL, DEFAULT_CANNED_ACL));
        if (!cannedACLName.isEmpty()) {
            cannedACL = CannedAccessControlList.valueOf(cannedACLName);
        } else {
            cannedACL = null;
        }

        if (!s3.doesBucketExist(bucket)) {
            throw new IOException("Bucket " + bucket + " does not exist");
        }

        boolean purgeExistingMultipart = conf.getBoolean(NEW_PURGE_EXISTING_MULTIPART,
                conf.getBoolean(OLD_PURGE_EXISTING_MULTIPART, DEFAULT_PURGE_EXISTING_MULTIPART));
        long purgeExistingMultipartAge = conf.getLong(NEW_PURGE_EXISTING_MULTIPART_AGE,
                conf.getLong(OLD_PURGE_EXISTING_MULTIPART_AGE, DEFAULT_PURGE_EXISTING_MULTIPART_AGE));

        if (purgeExistingMultipart) {
            TransferManager transferManager = new TransferManager(s3);
            Date purgeBefore = new Date(new Date().getTime() - purgeExistingMultipartAge * 1000);

            transferManager.abortMultipartUploads(bucket, purgeBefore);
            transferManager.shutdownNow(false);
        }

        serverSideEncryptionAlgorithm = conf.get(SERVER_SIDE_ENCRYPTION_ALGORITHM, null);

        setConf(conf);
    }

    /**
     * Return the protocol scheme for the FileSystem.
     *
     * @return "s3a"
     */
    public String getScheme() {
        return "s3a";
    }

    /** Returns a URI whose scheme and authority identify this FileSystem.*/
    public URI getUri() {
        return uri;
    }

    public S3AFileSystem() {
        super();
    }

    /* Turns a path (relative or otherwise) into an S3 key
     */
    private String pathToKey(Path path) {
        if (!path.isAbsolute()) {
            path = new Path(workingDir, path);
        }

        if (path.toUri().getScheme() != null && path.toUri().getPath().isEmpty()) {
            return "";
        }

        return path.toUri().getPath().substring(1);
    }

    private Path keyToPath(String key) {
        return new Path("/" + key);
    }

    /**
     * Opens an FSDataInputStream at the indicated Path.
     * @param f the file name to open
     * @param bufferSize the size of the buffer to be used.
     */
    public FSDataInputStream open(Path f, int bufferSize) throws IOException {

        LOG.info("Opening '" + f + "' for reading");
        final FileStatus fileStatus = getFileStatus(f);
        if (fileStatus.isDirectory()) {
            throw new IOException("Can't open " + f + " because it is a directory");
        }

        return new FSDataInputStream(new S3AInputStream(bucket, pathToKey(f), fileStatus.getLen(), s3, statistics));
    }

    /**
     * Create an FSDataOutputStream at the indicated Path with write-progress
     * reporting.
     * @param f the file name to open
     * @param permission
     * @param overwrite if a file with this name already exists, then if true,
     *   the file will be overwritten, and if false an error will be thrown.
     * @param bufferSize the size of the buffer to be used.
     * @param replication required block replication for the file.
     * @param blockSize
     * @param progress
     * @throws IOException
     * @see #setPermission(Path, FsPermission)
     */
    public FSDataOutputStream create(Path f, FsPermission permission, boolean overwrite, int bufferSize,
            short replication, long blockSize, Progressable progress) throws IOException {
        String key = pathToKey(f);

        if (!overwrite && exists(f)) {
            throw new IOException(f + " already exists");
        }

        // We pass null to FSDataOutputStream so it won't count writes that are being buffered to a file
        return new FSDataOutputStream(new S3AOutputStream(getConf(), s3, this, bucket, key, progress, cannedACL,
                statistics, serverSideEncryptionAlgorithm), null);
    }

    /**
     * Append to an existing file (optional operation).
     * @param f the existing file to be appended.
     * @param bufferSize the size of the buffer to be used.
     * @param progress for reporting progress if it is not null.
     * @throws IOException
     */
    public FSDataOutputStream append(Path f, int bufferSize, Progressable progress) throws IOException {
        throw new IOException("Not supported");
    }

    /**
     * Renames Path src to Path dst.  Can take place on local fs
     * or remote DFS.
     *
     * Warning: S3 does not support renames. This method does a copy which can take S3 some time to execute with large
     *          files and directories. Since there is no Progressable passed in, this can time out jobs.
     *
     * Note: This implementation differs with other S3 drivers. Specifically:
     *       Fails if src is a file and dst is a directory.
     *       Fails if src is a directory and dst is a file.
     *       Fails if the parent of dst does not exist or is a file.
     *       Fails if dst is a directory that is not empty.
     *
     * @param src path to be renamed
     * @param dst new path after rename
     * @throws IOException on failure
     * @return true if rename is successful
     */
    public boolean rename(Path src, Path dst) throws IOException {
        LOG.info("Rename path " + src + " to " + dst);

        String srcKey = pathToKey(src);
        String dstKey = pathToKey(dst);

        if (srcKey.length() == 0 || dstKey.length() == 0) {
            LOG.info("rename: src or dst are empty");
            return false;
        }

        if (srcKey.equals(dstKey)) {
            LOG.info("rename: src and dst refer to the same file");
            return true;
        }

        S3AFileStatus srcStatus;
        try {
            srcStatus = getFileStatus(src);
        } catch (FileNotFoundException e) {
            LOG.info("rename: src not found " + src);
            return false;
        }

        S3AFileStatus dstStatus = null;
        try {
            dstStatus = getFileStatus(dst);

            if (srcStatus.isFile() && dstStatus.isDirectory()) {
                LOG.info("rename: src is a file and dst is a directory");
                return false;
            }

            if (srcStatus.isDirectory() && dstStatus.isFile()) {
                LOG.info("rename: src is a directory and dst is a file");
                return false;
            }

            if (dstStatus.isDirectory() && !dstStatus.isEmptyDirectory()) {
                return false;
            }
        } catch (FileNotFoundException e) {
            // Parent must exist
            Path parent = dst.getParent();
            if (!pathToKey(parent).isEmpty()) {
                try {
                    S3AFileStatus dstParentStatus = getFileStatus(dst.getParent());
                    if (!dstParentStatus.isDirectory()) {
                        return false;
                    }
                } catch (FileNotFoundException e2) {
                    return false;
                }
            }
        }

        // Ok! Time to start
        if (srcStatus.isFile()) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("rename: renaming file " + src + " to " + dst);
            }
            copyFile(srcKey, dstKey);
            delete(src, false);
        } else {
            if (LOG.isDebugEnabled()) {
                LOG.debug("rename: renaming directory " + src + " to " + dst);
            }

            // This is a directory to directory copy
            if (!dstKey.endsWith("/")) {
                dstKey = dstKey + "/";
            }

            if (!srcKey.endsWith("/")) {
                srcKey = srcKey + "/";
            }

            List<DeleteObjectsRequest.KeyVersion> keysToDelete = new ArrayList<DeleteObjectsRequest.KeyVersion>();
            if (dstStatus != null && dstStatus.isEmptyDirectory()) {
                copyFile(srcKey, dstKey);
                statistics.incrementWriteOps(1);
                keysToDelete.add(new DeleteObjectsRequest.KeyVersion(srcKey));
            }

            ListObjectsRequest request = new ListObjectsRequest();
            request.setBucketName(bucket);
            request.setPrefix(srcKey);
            request.setMaxKeys(maxKeys);

            ObjectListing objects = s3.listObjects(request);
            statistics.incrementReadOps(1);

            while (true) {
                for (S3ObjectSummary summary : objects.getObjectSummaries()) {
                    keysToDelete.add(new DeleteObjectsRequest.KeyVersion(summary.getKey()));
                    String newDstKey = dstKey + summary.getKey().substring(srcKey.length());
                    copyFile(summary.getKey(), newDstKey);

                    if (keysToDelete.size() == MAX_ENTRIES_TO_DELETE) {
                        DeleteObjectsRequest deleteRequest = new DeleteObjectsRequest(bucket)
                                .withKeys(keysToDelete);
                        s3.deleteObjects(deleteRequest);
                        statistics.incrementWriteOps(1);
                        keysToDelete.clear();
                    }
                }

                if (objects.isTruncated()) {
                    objects = s3.listNextBatchOfObjects(objects);
                    statistics.incrementReadOps(1);
                } else {
                    break;
                }
            }

            if (!keysToDelete.isEmpty()) {
                DeleteObjectsRequest deleteRequest = new DeleteObjectsRequest(bucket);
                deleteRequest.setKeys(keysToDelete);
                s3.deleteObjects(deleteRequest);
                statistics.incrementWriteOps(1);
            }
        }

        if (src.getParent() != dst.getParent()) {
            deleteUnnecessaryFakeDirectories(dst.getParent());
            createFakeDirectoryIfNecessary(src.getParent());
        }
        return true;
    }

    /** Delete a file.
     *
     * @param f the path to delete.
     * @param recursive if path is a directory and set to
     * true, the directory is deleted else throws an exception. In
     * case of a file the recursive can be set to either true or false.
     * @return  true if delete is successful else false.
     * @throws IOException
     */
    public boolean delete(Path f, boolean recursive) throws IOException {
        LOG.info("Delete path " + f + " - recursive " + recursive);
        S3AFileStatus status;
        try {
            status = getFileStatus(f);
        } catch (FileNotFoundException e) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Couldn't delete " + f + " - does not exist");
            }
            return false;
        }

        String key = pathToKey(f);

        if (status.isDirectory()) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("delete: Path is a directory");
            }

            if (!recursive) {
                throw new IOException("Path is a folder: " + f);
            }

            if (!key.endsWith("/")) {
                key = key + "/";
            }

            if (status.isEmptyDirectory()) {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("Deleting fake empty directory");
                }
                s3.deleteObject(bucket, key);
                statistics.incrementWriteOps(1);
            } else {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("Getting objects for directory prefix " + key + " to delete");
                }

                ListObjectsRequest request = new ListObjectsRequest();
                request.setBucketName(bucket);
                request.setPrefix(key);
                // Hopefully not setting a delimiter will cause this to find everything
                //request.setDelimiter("/");
                request.setMaxKeys(maxKeys);

                List<DeleteObjectsRequest.KeyVersion> keys = new ArrayList<DeleteObjectsRequest.KeyVersion>();
                ObjectListing objects = s3.listObjects(request);
                statistics.incrementReadOps(1);
                while (true) {
                    for (S3ObjectSummary summary : objects.getObjectSummaries()) {
                        keys.add(new DeleteObjectsRequest.KeyVersion(summary.getKey()));
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("Got object to delete " + summary.getKey());
                        }

                        if (keys.size() == MAX_ENTRIES_TO_DELETE) {
                            DeleteObjectsRequest deleteRequest = new DeleteObjectsRequest(bucket).withKeys(keys);
                            s3.deleteObjects(deleteRequest);
                            statistics.incrementWriteOps(1);
                            keys.clear();
                        }
                    }

                    if (objects.isTruncated()) {
                        objects = s3.listNextBatchOfObjects(objects);
                        statistics.incrementReadOps(1);
                    } else {
                        break;
                    }
                }

                if (!keys.isEmpty()) {
                    DeleteObjectsRequest deleteRequest = new DeleteObjectsRequest(bucket).withKeys(keys);
                    s3.deleteObjects(deleteRequest);
                    statistics.incrementWriteOps(1);
                }
            }
        } else {
            if (LOG.isDebugEnabled()) {
                LOG.debug("delete: Path is a file");
            }
            s3.deleteObject(bucket, key);
            statistics.incrementWriteOps(1);
        }

        createFakeDirectoryIfNecessary(f.getParent());

        return true;
    }

    private void createFakeDirectoryIfNecessary(Path f) throws IOException {
        String key = pathToKey(f);
        if (!key.isEmpty() && !exists(f)) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Creating new fake directory at " + f);
            }
            createFakeDirectory(bucket, key);
        }
    }

    /**
     * List the statuses of the files/directories in the given path if the path is
     * a directory.
     *
     * @param f given path
     * @return the statuses of the files/directories in the given patch
     * @throws FileNotFoundException when the path does not exist;
     *         IOException see specific implementation
     */
    public FileStatus[] listStatus(Path f) throws FileNotFoundException, IOException {
        String key = pathToKey(f);
        LOG.info("List status for path: " + f);

        final List<FileStatus> result = new ArrayList<FileStatus>();
        final FileStatus fileStatus = getFileStatus(f);

        if (fileStatus.isDirectory()) {
            if (!key.isEmpty()) {
                key = key + "/";
            }

            ListObjectsRequest request = new ListObjectsRequest();
            request.setBucketName(bucket);
            request.setPrefix(key);
            request.setDelimiter("/");
            request.setMaxKeys(maxKeys);

            if (LOG.isDebugEnabled()) {
                LOG.debug("listStatus: doing listObjects for directory " + key);
            }

            ObjectListing objects = s3.listObjects(request);
            statistics.incrementReadOps(1);

            while (true) {
                for (S3ObjectSummary summary : objects.getObjectSummaries()) {
                    Path keyPath = keyToPath(summary.getKey()).makeQualified(uri, workingDir);
                    // Skip over keys that are ourselves and old S3N _$folder$ files
                    if (keyPath.equals(f) || summary.getKey().endsWith(S3N_FOLDER_SUFFIX)) {
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("Ignoring: " + keyPath);
                        }
                        continue;
                    }

                    if (objectRepresentsDirectory(summary.getKey(), summary.getSize())) {
                        result.add(new S3AFileStatus(true, true, keyPath));
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("Adding: fd: " + keyPath);
                        }
                    } else {
                        result.add(new S3AFileStatus(summary.getSize(), dateToLong(summary.getLastModified()),
                                keyPath));
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("Adding: fi: " + keyPath);
                        }
                    }
                }

                for (String prefix : objects.getCommonPrefixes()) {
                    Path keyPath = keyToPath(prefix).makeQualified(uri, workingDir);
                    if (keyPath.equals(f)) {
                        continue;
                    }
                    result.add(new S3AFileStatus(true, false, keyPath));
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Adding: rd: " + keyPath);
                    }
                }

                if (objects.isTruncated()) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("listStatus: list truncated - getting next batch");
                    }

                    objects = s3.listNextBatchOfObjects(objects);
                    statistics.incrementReadOps(1);
                } else {
                    break;
                }
            }
        } else {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Adding: rd (not a dir): " + f);
            }
            result.add(fileStatus);
        }

        return result.toArray(new FileStatus[result.size()]);
    }

    /**
     * Set the current working directory for the given file system. All relative
     * paths will be resolved relative to it.
     *
     * @param new_dir
     */
    public void setWorkingDirectory(Path new_dir) {
        workingDir = new_dir;
    }

    /**
     * Get the current working directory for the given file system
     * @return the directory pathname
     */
    public Path getWorkingDirectory() {
        return workingDir;
    }

    /**
     * Make the given file and all non-existent parents into
     * directories. Has the semantics of Unix 'mkdir -p'.
     * Existence of the directory hierarchy is not an error.
     * @param f path to create
     * @param permission to apply to f
     */
    // TODO: If we have created an empty file at /foo/bar and we then call mkdirs for /foo/bar/baz/roo what happens to the empty file /foo/bar/?
    public boolean mkdirs(Path f, FsPermission permission) throws IOException {
        LOG.info("Making directory: " + f);

        try {
            FileStatus fileStatus = getFileStatus(f);

            if (fileStatus.isDirectory()) {
                return true;
            } else {
                throw new IOException("Path is a file: " + f);
            }
        } catch (FileNotFoundException e) {
            String key = pathToKey(f);
            createFakeDirectory(bucket, key);
            return true;
        }
    }

    /**
     * Return a file status object that represents the path.
     * @param f The path we want information from
     * @return a FileStatus object
     * @throws java.io.FileNotFoundException when the path does not exist;
     *         IOException see specific implementation
     */
    public S3AFileStatus getFileStatus(Path f) throws IOException {
        String key = pathToKey(f);

        LOG.info("Getting path status for " + f + " (" + key + ")");

        if (!key.isEmpty()) {
            try {
                ObjectMetadata meta = s3.getObjectMetadata(bucket, key);
                statistics.incrementReadOps(1);

                if (objectRepresentsDirectory(key, meta.getContentLength())) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Found exact file: fake directory");
                    }
                    return new S3AFileStatus(true, true, f.makeQualified(uri, workingDir));
                } else {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Found exact file: normal file");
                    }
                    return new S3AFileStatus(meta.getContentLength(), dateToLong(meta.getLastModified()),
                            f.makeQualified(uri, workingDir));
                }
            } catch (AmazonServiceException e) {
                if (e.getStatusCode() != 404) {
                    printAmazonServiceException(e);
                    throw e;
                }
            } catch (AmazonClientException e) {
                printAmazonClientException(e);
                throw e;
            }

            // Necessary?
            if (!key.endsWith("/")) {
                try {
                    String newKey = key + "/";
                    ObjectMetadata meta = s3.getObjectMetadata(bucket, newKey);
                    statistics.incrementReadOps(1);

                    if (objectRepresentsDirectory(newKey, meta.getContentLength())) {
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("Found file (with /): fake directory");
                        }
                        return new S3AFileStatus(true, true, f.makeQualified(uri, workingDir));
                    } else {
                        LOG.warn("Found file (with /): real file? should not happen: " + key);

                        return new S3AFileStatus(meta.getContentLength(), dateToLong(meta.getLastModified()),
                                f.makeQualified(uri, workingDir));
                    }
                } catch (AmazonServiceException e) {
                    if (e.getStatusCode() != 404) {
                        printAmazonServiceException(e);
                        throw e;
                    }
                } catch (AmazonClientException e) {
                    printAmazonClientException(e);
                    throw e;
                }
            }
        }

        try {
            if (!key.isEmpty() && !key.endsWith("/")) {
                key = key + "/";
            }
            ListObjectsRequest request = new ListObjectsRequest();
            request.setBucketName(bucket);
            request.setPrefix(key);
            request.setDelimiter("/");
            request.setMaxKeys(1);

            ObjectListing objects = s3.listObjects(request);
            statistics.incrementReadOps(1);

            if (objects.getCommonPrefixes().size() > 0 || objects.getObjectSummaries().size() > 0) {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("Found path as directory (with /): " + objects.getCommonPrefixes().size() + "/"
                            + objects.getObjectSummaries().size());

                    for (S3ObjectSummary summary : objects.getObjectSummaries()) {
                        LOG.debug("Summary: " + summary.getKey() + " " + summary.getSize());
                    }
                    for (String prefix : objects.getCommonPrefixes()) {
                        LOG.debug("Prefix: " + prefix);
                    }
                }

                return new S3AFileStatus(true, false, f.makeQualified(uri, workingDir));
            }
        } catch (AmazonServiceException e) {
            if (e.getStatusCode() != 404) {
                printAmazonServiceException(e);
                throw e;
            }
        } catch (AmazonClientException e) {
            printAmazonClientException(e);
            throw e;
        }

        if (LOG.isDebugEnabled()) {
            LOG.debug("Not Found: " + f);
        }
        throw new FileNotFoundException("No such file or directory: " + f);
    }

    /**
     * The src file is on the local disk.  Add it to FS at
     * the given dst name.
     *
     * This version doesn't need to create a temporary file to calculate the md5. Sadly this doesn't seem to be
     * used by the shell cp :(
     *
     * delSrc indicates if the source should be removed
     * @param delSrc whether to delete the src
     * @param overwrite whether to overwrite an existing file
     * @param src path
     * @param dst path
     */
    @Override
    public void copyFromLocalFile(boolean delSrc, boolean overwrite, Path src, Path dst) throws IOException {
        String key = pathToKey(dst);

        if (!overwrite && exists(dst)) {
            throw new IOException(dst + " already exists");
        }

        LOG.info("Copying local file from " + src + " to " + dst);

        // Since we have a local file, we don't need to stream into a temporary file
        LocalFileSystem local = getLocal(getConf());
        File srcfile = local.pathToFile(src);

        TransferManagerConfiguration transferConfiguration = new TransferManagerConfiguration();
        transferConfiguration.setMinimumUploadPartSize(partSize);
        transferConfiguration.setMultipartUploadThreshold(partSizeThreshold);

        TransferManager transfers = new TransferManager(s3);
        transfers.setConfiguration(transferConfiguration);

        final ObjectMetadata om = new ObjectMetadata();
        if (StringUtils.isNotBlank(serverSideEncryptionAlgorithm)) {
            om.setServerSideEncryption(serverSideEncryptionAlgorithm);
        }

        PutObjectRequest putObjectRequest = new PutObjectRequest(bucket, key, srcfile);
        putObjectRequest.setCannedAcl(cannedACL);
        putObjectRequest.setMetadata(om);

        ProgressListener progressListener = new ProgressListener() {
            public void progressChanged(ProgressEvent progressEvent) {
                switch (progressEvent.getEventCode()) {
                case ProgressEvent.PART_COMPLETED_EVENT_CODE:
                    statistics.incrementWriteOps(1);
                    break;
                }
            }
        };

        Upload up = transfers.upload(putObjectRequest);
        up.addProgressListener(progressListener);
        try {
            up.waitForUploadResult();
            statistics.incrementWriteOps(1);
        } catch (InterruptedException e) {
            throw new IOException("Got interrupted, cancelling");
        } finally {
            transfers.shutdownNow(false);
        }

        // This will delete unnecessary fake parent directories
        finishedWrite(key);

        if (delSrc) {
            local.delete(src, false);
        }
    }

    /**
     * Override getCanonicalServiceName because we don't support token in S3A
     */
    @Override
    public String getCanonicalServiceName() {
        // Does not support Token
        return null;
    }

    private void copyFile(String srcKey, String dstKey) throws IOException {
        if (LOG.isDebugEnabled()) {
            LOG.debug("copyFile " + srcKey + " -> " + dstKey);
        }

        TransferManagerConfiguration transferConfiguration = new TransferManagerConfiguration();
        transferConfiguration.setMultipartCopyPartSize(partSize);

        TransferManager transfers = new TransferManager(s3);
        transfers.setConfiguration(transferConfiguration);

        ObjectMetadata srcom = s3.getObjectMetadata(bucket, srcKey);
        final ObjectMetadata dstom = srcom.clone();
        if (StringUtils.isNotBlank(serverSideEncryptionAlgorithm)) {
            dstom.setServerSideEncryption(serverSideEncryptionAlgorithm);
        }

        CopyObjectRequest copyObjectRequest = new CopyObjectRequest(bucket, srcKey, bucket, dstKey);
        copyObjectRequest.setCannedAccessControlList(cannedACL);
        copyObjectRequest.setNewObjectMetadata(dstom);

        ProgressListener progressListener = new ProgressListener() {
            public void progressChanged(ProgressEvent progressEvent) {
                switch (progressEvent.getEventCode()) {
                case ProgressEvent.PART_COMPLETED_EVENT_CODE:
                    statistics.incrementWriteOps(1);
                    break;
                }
            }
        };

        Copy copy = transfers.copy(copyObjectRequest);
        copy.addProgressListener(progressListener);
        try {
            copy.waitForCopyResult();
            statistics.incrementWriteOps(1);
        } catch (InterruptedException e) {
            throw new IOException("Got interrupted, cancelling");
        } finally {
            transfers.shutdownNow(false);
        }
    }

    private boolean objectRepresentsDirectory(final String name, final long size) {
        return !name.isEmpty() && name.charAt(name.length() - 1) == '/' && size == 0L;
    }

    // Handles null Dates that can be returned by AWS
    private static long dateToLong(final Date date) {
        if (date == null) {
            return 0L;
        }

        return date.getTime();
    }

    public void finishedWrite(String key) throws IOException {
        deleteUnnecessaryFakeDirectories(keyToPath(key).getParent());
    }

    private void deleteUnnecessaryFakeDirectories(Path f) throws IOException {
        while (true) {
            try {
                String key = pathToKey(f);
                if (key.isEmpty()) {
                    break;
                }

                S3AFileStatus status = getFileStatus(f);

                if (status.isDirectory() && status.isEmptyDirectory()) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Deleting fake directory " + key + "/");
                    }
                    s3.deleteObject(bucket, key + "/");
                    statistics.incrementWriteOps(1);
                }
            } catch (FileNotFoundException e) {
            } catch (AmazonServiceException e) {
            }

            if (f.isRoot()) {
                break;
            }

            f = f.getParent();
        }
    }

    private void createFakeDirectory(final String bucketName, final String objectName)
            throws AmazonClientException, AmazonServiceException {
        if (!objectName.endsWith("/")) {
            createEmptyObject(bucketName, objectName + "/");
        } else {
            createEmptyObject(bucketName, objectName);
        }
    }

    // Used to create an empty file that represents an empty directory
    private void createEmptyObject(final String bucketName, final String objectName)
            throws AmazonClientException, AmazonServiceException {
        final InputStream im = new InputStream() {
            @Override
            public int read() throws IOException {
                return -1;
            }
        };

        final ObjectMetadata om = new ObjectMetadata();
        om.setContentLength(0L);
        if (StringUtils.isNotBlank(serverSideEncryptionAlgorithm)) {
            om.setServerSideEncryption(serverSideEncryptionAlgorithm);
        }
        PutObjectRequest putObjectRequest = new PutObjectRequest(bucketName, objectName, im, om);
        putObjectRequest.setCannedAcl(cannedACL);
        s3.putObject(putObjectRequest);
        statistics.incrementWriteOps(1);
    }

    /**
     * Return the number of bytes that large input files should be optimally
     * be split into to minimize i/o time.
     * @deprecated use {@link #getDefaultBlockSize(Path)} instead
     */
    @Deprecated
    public long getDefaultBlockSize() {
        // default to 32MB: large enough to minimize the impact of seeks
        return getConf().getLong("fs.s3a.block.size", 32 * 1024 * 1024);
    }

    private void printAmazonServiceException(AmazonServiceException ase) {
        LOG.info("Caught an AmazonServiceException, which means your request made it "
                + "to Amazon S3, but was rejected with an error response for some reason.");
        LOG.info("Error Message: " + ase.getMessage());
        LOG.info("HTTP Status Code: " + ase.getStatusCode());
        LOG.info("AWS Error Code: " + ase.getErrorCode());
        LOG.info("Error Type: " + ase.getErrorType());
        LOG.info("Request ID: " + ase.getRequestId());
        LOG.info("Class Name: " + ase.getClass().getName());
    }

    private void printAmazonClientException(AmazonClientException ace) {
        LOG.info("Caught an AmazonClientException, which means the client encountered "
                + "a serious internal problem while trying to communicate with S3, "
                + "such as not being able to access the network.");
        LOG.info("Error Message: " + ace.getMessage());
    }
}