Java tutorial
/* * Licensed to Metamarkets Group Inc. (Metamarkets) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. Metamarkets 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 io.druid.storage.s3; import com.amazonaws.AmazonServiceException; import com.amazonaws.services.s3.AmazonS3; import com.amazonaws.services.s3.model.AccessControlList; import com.amazonaws.services.s3.model.AmazonS3Exception; import com.amazonaws.services.s3.model.CanonicalGrantee; import com.amazonaws.services.s3.model.Grant; import com.amazonaws.services.s3.model.ListObjectsV2Request; import com.amazonaws.services.s3.model.ListObjectsV2Result; import com.amazonaws.services.s3.model.ObjectMetadata; import com.amazonaws.services.s3.model.Permission; import com.amazonaws.services.s3.model.S3ObjectSummary; import com.google.common.base.Joiner; import com.google.common.base.Predicate; import io.druid.java.util.common.ISE; import io.druid.java.util.common.RetryUtils; import io.druid.java.util.common.RetryUtils.Task; import java.io.IOException; import java.net.URI; import java.util.Iterator; import java.util.NoSuchElementException; /** * */ public class S3Utils { private static final Joiner JOINER = Joiner.on("/").skipNulls(); private static final String MIMETYPE_JETS3T_DIRECTORY = "application/x-directory"; static boolean isServiceExceptionRecoverable(AmazonServiceException ex) { final boolean isIOException = ex.getCause() instanceof IOException; final boolean isTimeout = "RequestTimeout".equals(ex.getErrorCode()); return isIOException || isTimeout; } public static final Predicate<Throwable> S3RETRY = new Predicate<Throwable>() { @Override public boolean apply(Throwable e) { if (e == null) { return false; } else if (e instanceof IOException) { return true; } else if (e instanceof AmazonServiceException) { return isServiceExceptionRecoverable((AmazonServiceException) e); } else { return apply(e.getCause()); } } }; /** * Retries S3 operations that fail due to io-related exceptions. Service-level exceptions (access denied, file not * found, etc) are not retried. */ public static <T> T retryS3Operation(Task<T> f) throws Exception { final int maxTries = 10; return RetryUtils.retry(f, S3RETRY, maxTries); } static boolean isObjectInBucketIgnoringPermission(AmazonS3 s3Client, String bucketName, String objectKey) { try { return s3Client.doesObjectExist(bucketName, objectKey); } catch (AmazonS3Exception e) { if (e.getStatusCode() == 404) { // Object is inaccessible to current user, but does exist. return true; } // Something else has gone wrong throw e; } } public static Iterator<S3ObjectSummary> objectSummaryIterator(final AmazonS3 s3Client, final String bucket, final String prefix, final int numMaxKeys) { final ListObjectsV2Request request = new ListObjectsV2Request().withBucketName(bucket).withPrefix(prefix) .withMaxKeys(numMaxKeys); return new Iterator<S3ObjectSummary>() { private ListObjectsV2Result result; private Iterator<S3ObjectSummary> objectSummaryIterator; { fetchNextBatch(); } private void fetchNextBatch() { result = s3Client.listObjectsV2(request); objectSummaryIterator = result.getObjectSummaries().iterator(); request.setContinuationToken(result.getContinuationToken()); } @Override public boolean hasNext() { return objectSummaryIterator.hasNext() || result.isTruncated(); } @Override public S3ObjectSummary next() { if (!hasNext()) { throw new NoSuchElementException(); } if (objectSummaryIterator.hasNext()) { return objectSummaryIterator.next(); } if (result.isTruncated()) { fetchNextBatch(); } if (!objectSummaryIterator.hasNext()) { throw new ISE( "Failed to further iterate on bucket[%s] and prefix[%s]. The last continuationToken was [%s]", bucket, prefix, result.getContinuationToken()); } return objectSummaryIterator.next(); } }; } public static String constructSegmentPath(String baseKey, String storageDir) { return JOINER.join(baseKey.isEmpty() ? null : baseKey, storageDir) + "/index.zip"; } static String descriptorPathForSegmentPath(String s3Path) { return s3Path.substring(0, s3Path.lastIndexOf("/")) + "/descriptor.json"; } static String indexZipForSegmentPath(String s3Path) { return s3Path.substring(0, s3Path.lastIndexOf("/")) + "/index.zip"; } static String toFilename(String key) { return toFilename(key, ""); } static String toFilename(String key, final String suffix) { String filename = key.substring(key.lastIndexOf("/") + 1); // characters after last '/' filename = filename.substring(0, filename.length() - suffix.length()); // remove the suffix from the end return filename; } static AccessControlList grantFullControlToBucketOwner(AmazonS3 s3Client, String bucket) { final AccessControlList acl = s3Client.getBucketAcl(bucket); acl.grantAllPermissions(new Grant(new CanonicalGrantee(acl.getOwner().getId()), Permission.FullControl)); return acl; } public static String extractS3Key(URI uri) { return uri.getPath().startsWith("/") ? uri.getPath().substring(1) : uri.getPath(); } // Copied from org.jets3t.service.model.StorageObject.isDirectoryPlaceholder() public static boolean isDirectoryPlaceholder(String key, ObjectMetadata objectMetadata) { // Recognize "standard" directory place-holder indications used by // Amazon's AWS Console and Panic's Transmit. if (key.endsWith("/") && objectMetadata.getContentLength() == 0) { return true; } // Recognize s3sync.rb directory placeholders by MD5/ETag value. if ("d66759af42f282e1ba19144df2d405d0".equals(objectMetadata.getETag())) { return true; } // Recognize place-holder objects created by the Google Storage console // or S3 Organizer Firefox extension. if (key.endsWith("_$folder$") && objectMetadata.getContentLength() == 0) { return true; } // We don't use JetS3t APIs anymore, but the below check is still needed for backward compatibility. // Recognize legacy JetS3t directory place-holder objects, only gives // accurate results if an object's metadata is populated. if (objectMetadata.getContentLength() == 0 && MIMETYPE_JETS3T_DIRECTORY.equals(objectMetadata.getContentType())) { return true; } return false; } /** * Gets a single {@link S3ObjectSummary} from s3. Since this method might return a wrong object if there are multiple * objects that match the given key, this method should be used only when it's guaranteed that the given key is unique * in the given bucket. * * @param s3Client s3 client * @param bucket s3 bucket * @param key unique key for the object to be retrieved */ public static S3ObjectSummary getSingleObjectSummary(AmazonS3 s3Client, String bucket, String key) { final ListObjectsV2Request request = new ListObjectsV2Request().withBucketName(bucket).withPrefix(key) .withMaxKeys(1); final ListObjectsV2Result result = s3Client.listObjectsV2(request); if (result.getKeyCount() == 0) { throw new ISE("Cannot find object for bucket[%s] and key[%s]", bucket, key); } final S3ObjectSummary objectSummary = result.getObjectSummaries().get(0); if (!objectSummary.getBucketName().equals(bucket) || !objectSummary.getKey().equals(key)) { throw new ISE("Wrong object[%s] for bucket[%s] and key[%s]", objectSummary, bucket, key); } return objectSummary; } }