FrankChen021 commented on a change in pull request #9898: URL: https://github.com/apache/druid/pull/9898#discussion_r446116676
########## File path: extensions-contrib/aliyun-oss-extensions/src/main/java/org/apache/druid/storage/aliyun/ObjectSummaryIterator.java ########## @@ -0,0 +1,163 @@ +/* + * 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.aliyun; + +import com.aliyun.oss.OSS; +import com.aliyun.oss.OSSException; +import com.aliyun.oss.model.ListObjectsRequest; +import com.aliyun.oss.model.OSSObjectSummary; +import com.aliyun.oss.model.ObjectListing; +import org.apache.druid.java.util.common.RE; + +import java.net.URI; +import java.util.Iterator; +import java.util.NoSuchElementException; + +/** + * Iterator class used by {@link OssUtils#objectSummaryIterator}. + * <p> + * As required by the specification of that method, this iterator is computed incrementally in batches of + * {@code maxListLength}. The first call is made at the same time the iterator is constructed. + * + */ +public class ObjectSummaryIterator implements Iterator<OSSObjectSummary> +{ + private final OSS client; + private final Iterator<URI> prefixesIterator; + private final int maxListingLength; + + private ListObjectsRequest request; + private ObjectListing result; + private Iterator<OSSObjectSummary> objectSummaryIterator; + private OSSObjectSummary currentObjectSummary; + + ObjectSummaryIterator( + final OSS client, + final Iterable<URI> prefixes, + final int maxListingLength + ) + { + this.client = client; + this.prefixesIterator = prefixes.iterator(); + this.maxListingLength = maxListingLength; + + prepareNextRequest(); + fetchNextBatch(); + advanceObjectSummary(); + } + + @Override + public boolean hasNext() + { + return currentObjectSummary != null; + } + + @Override + public OSSObjectSummary next() + { + if (currentObjectSummary == null) { + throw new NoSuchElementException(); + } + + final OSSObjectSummary retVal = currentObjectSummary; + advanceObjectSummary(); + return retVal; + } + + private void prepareNextRequest() + { + final URI currentUri = prefixesIterator.next(); + final String currentBucket = currentUri.getAuthority(); + final String currentPrefix = OssUtils.extractKey(currentUri); + + request = new ListObjectsRequest(currentBucket, currentPrefix, null, null, maxListingLength); + } + + private void fetchNextBatch() + { + try { + result = OssUtils.retry(() -> client.listObjects(request)); + request.setMarker(result.getNextMarker()); + objectSummaryIterator = result.getObjectSummaries().iterator(); + } + catch (OSSException e) { + throw new RE( + e, + "Failed to get object summaries from S3 bucket[%s], prefix[%s]; S3 error: %s", + request.getBucketName(), + request.getPrefix(), + e.getMessage() + ); + } + catch (Exception e) { + throw new RE( + e, + "Failed to get object summaries from S3 bucket[%s], prefix[%s]", + request.getBucketName(), + request.getPrefix() + ); + } + } + + /** + * Advance objectSummaryIterator to the next non-placeholder, updating "currentObjectSummary". + */ + private void advanceObjectSummary() + { + while (objectSummaryIterator.hasNext() || result.isTruncated() || prefixesIterator.hasNext()) { + while (objectSummaryIterator.hasNext()) { + currentObjectSummary = objectSummaryIterator.next(); + // skips directories and empty objects + if (!isDirectoryPlaceholder(currentObjectSummary) && currentObjectSummary.getSize() > 0) { + return; + } + } + + // Exhausted "objectSummaryIterator" without finding a non-placeholder. + if (result.isTruncated()) { + fetchNextBatch(); + } else if (prefixesIterator.hasNext()) { + prepareNextRequest(); + fetchNextBatch(); + } + } + + // Truly nothing left to read. + currentObjectSummary = null; + } + + /** + * Checks if a given object is a directory placeholder and should be ignored. Review comment: @jon-wei LICENSE has been updated in the lastest commit, please check it again. ########## File path: extensions-contrib/aliyun-oss-extensions/src/main/java/org/apache/druid/storage/aliyun/ObjectSummaryIterator.java ########## @@ -0,0 +1,163 @@ +/* + * 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.aliyun; + +import com.aliyun.oss.OSS; +import com.aliyun.oss.OSSException; +import com.aliyun.oss.model.ListObjectsRequest; +import com.aliyun.oss.model.OSSObjectSummary; +import com.aliyun.oss.model.ObjectListing; +import org.apache.druid.java.util.common.RE; + +import java.net.URI; +import java.util.Iterator; +import java.util.NoSuchElementException; + +/** + * Iterator class used by {@link OssUtils#objectSummaryIterator}. + * <p> + * As required by the specification of that method, this iterator is computed incrementally in batches of + * {@code maxListLength}. The first call is made at the same time the iterator is constructed. + * + */ +public class ObjectSummaryIterator implements Iterator<OSSObjectSummary> +{ + private final OSS client; + private final Iterator<URI> prefixesIterator; + private final int maxListingLength; + + private ListObjectsRequest request; + private ObjectListing result; + private Iterator<OSSObjectSummary> objectSummaryIterator; + private OSSObjectSummary currentObjectSummary; + + ObjectSummaryIterator( + final OSS client, + final Iterable<URI> prefixes, + final int maxListingLength + ) + { + this.client = client; + this.prefixesIterator = prefixes.iterator(); + this.maxListingLength = maxListingLength; + + prepareNextRequest(); + fetchNextBatch(); + advanceObjectSummary(); + } + + @Override + public boolean hasNext() + { + return currentObjectSummary != null; + } + + @Override + public OSSObjectSummary next() + { + if (currentObjectSummary == null) { + throw new NoSuchElementException(); + } + + final OSSObjectSummary retVal = currentObjectSummary; + advanceObjectSummary(); + return retVal; + } + + private void prepareNextRequest() + { + final URI currentUri = prefixesIterator.next(); + final String currentBucket = currentUri.getAuthority(); + final String currentPrefix = OssUtils.extractKey(currentUri); + + request = new ListObjectsRequest(currentBucket, currentPrefix, null, null, maxListingLength); + } + + private void fetchNextBatch() + { + try { + result = OssUtils.retry(() -> client.listObjects(request)); + request.setMarker(result.getNextMarker()); + objectSummaryIterator = result.getObjectSummaries().iterator(); + } + catch (OSSException e) { + throw new RE( + e, + "Failed to get object summaries from S3 bucket[%s], prefix[%s]; S3 error: %s", + request.getBucketName(), + request.getPrefix(), + e.getMessage() + ); + } + catch (Exception e) { + throw new RE( + e, + "Failed to get object summaries from S3 bucket[%s], prefix[%s]", + request.getBucketName(), + request.getPrefix() + ); + } + } + + /** + * Advance objectSummaryIterator to the next non-placeholder, updating "currentObjectSummary". + */ + private void advanceObjectSummary() + { + while (objectSummaryIterator.hasNext() || result.isTruncated() || prefixesIterator.hasNext()) { + while (objectSummaryIterator.hasNext()) { + currentObjectSummary = objectSummaryIterator.next(); + // skips directories and empty objects + if (!isDirectoryPlaceholder(currentObjectSummary) && currentObjectSummary.getSize() > 0) { + return; + } + } + + // Exhausted "objectSummaryIterator" without finding a non-placeholder. + if (result.isTruncated()) { + fetchNextBatch(); + } else if (prefixesIterator.hasNext()) { + prepareNextRequest(); + fetchNextBatch(); + } + } + + // Truly nothing left to read. + currentObjectSummary = null; + } + + /** + * Checks if a given object is a directory placeholder and should be ignored. Review comment: @jon-wei LICENSE has been updated in the latest commit, please check it again. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org For additional commands, e-mail: commits-h...@druid.apache.org
