Java tutorial
/* * 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.druid.storage.s3; import com.amazonaws.services.s3.model.S3ObjectSummary; import com.google.inject.Inject; import org.apache.druid.data.SearchableVersionedDataFinder; import org.apache.druid.java.util.common.RetryUtils; import org.apache.druid.java.util.common.StringUtils; import javax.annotation.Nullable; import java.net.URI; import java.util.Iterator; import java.util.regex.Pattern; public class S3TimestampVersionedDataFinder extends S3DataSegmentPuller implements SearchableVersionedDataFinder<URI> { private static final int MAX_LISTING_KEYS = 1000; @Inject public S3TimestampVersionedDataFinder(ServerSideEncryptingAmazonS3 s3Client) { super(s3Client); } /** * Gets the key with the most recently modified timestamp. * `pattern` is evaluated against the entire key AFTER the path given in `uri`. * The substring `pattern` is matched against will have a leading `/` removed. * For example `s3://some_bucket/some_prefix/some_key` with a URI of `s3://some_bucket/some_prefix` will match against `some_key`. * `s3://some_bucket/some_prefixsome_key` with a URI of `s3://some_bucket/some_prefix` will match against `some_key` * `s3://some_bucket/some_prefix//some_key` with a URI of `s3://some_bucket/some_prefix` will match against `/some_key` * * @param uri The URI of in the form of `s3://some_bucket/some_key` * @param pattern The pattern matcher to determine if a *key* is of interest, or `null` to match everything. * * @return A URI to the most recently modified object which matched the pattern. */ @Override public URI getLatestVersion(final URI uri, final @Nullable Pattern pattern) { try { return RetryUtils.retry(() -> { final S3Coords coords = new S3Coords(checkURI(uri)); long mostRecent = Long.MIN_VALUE; URI latest = null; final Iterator<S3ObjectSummary> objectSummaryIterator = S3Utils.objectSummaryIterator(s3Client, coords.bucket, coords.path, MAX_LISTING_KEYS); while (objectSummaryIterator.hasNext()) { final S3ObjectSummary objectSummary = objectSummaryIterator.next(); String keyString = objectSummary.getKey().substring(coords.path.length()); if (keyString.startsWith("/")) { keyString = keyString.substring(1); } if (pattern != null && !pattern.matcher(keyString).matches()) { continue; } final long latestModified = objectSummary.getLastModified().getTime(); if (latestModified >= mostRecent) { mostRecent = latestModified; latest = new URI(StringUtils.format("s3://%s/%s", objectSummary.getBucketName(), objectSummary.getKey())); } } return latest; }, shouldRetryPredicate(), DEFAULT_RETRY_COUNT); } catch (Exception e) { throw new RuntimeException(e); } } }