| /** |
| * 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.distributedlog.basic; |
| |
| import static com.google.common.base.Charsets.UTF_8; |
| |
| import java.net.URI; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| import org.apache.distributedlog.api.AsyncLogReader; |
| import org.apache.distributedlog.DistributedLogConfiguration; |
| import org.apache.distributedlog.api.DistributedLogManager; |
| import org.apache.distributedlog.LogRecordWithDLSN; |
| import org.apache.distributedlog.api.namespace.Namespace; |
| import org.apache.distributedlog.api.namespace.NamespaceBuilder; |
| import org.apache.distributedlog.common.concurrent.FutureEventListener; |
| import org.apache.distributedlog.common.concurrent.FutureUtils; |
| |
| /** |
| * Rewind a stream to read data back in a while |
| */ |
| public class StreamRewinder { |
| |
| private final static String HELP = "StreamRewinder <uri> <string> <seconds>"; |
| |
| public static void main(String[] args) throws Exception { |
| if (3 != args.length) { |
| System.out.println(HELP); |
| return; |
| } |
| |
| String dlUriStr = args[0]; |
| final String streamName = args[1]; |
| final int rewindSeconds = Integer.parseInt(args[2]); |
| |
| URI uri = URI.create(dlUriStr); |
| DistributedLogConfiguration conf = new DistributedLogConfiguration(); |
| Namespace namespace = NamespaceBuilder.newBuilder() |
| .conf(conf) |
| .uri(uri) |
| .build(); |
| |
| // open the dlm |
| System.out.println("Opening log stream " + streamName); |
| DistributedLogManager dlm = namespace.openLog(streamName); |
| |
| try { |
| readLoop(dlm, rewindSeconds); |
| } finally { |
| dlm.close(); |
| namespace.close(); |
| } |
| } |
| |
| private static void readLoop(final DistributedLogManager dlm, |
| final int rewindSeconds) throws Exception { |
| |
| final CountDownLatch keepAliveLatch = new CountDownLatch(1); |
| |
| long rewindToTxId = System.currentTimeMillis() - |
| TimeUnit.MILLISECONDS.convert(rewindSeconds, TimeUnit.SECONDS); |
| |
| System.out.println("Record records starting from " + rewindToTxId |
| + " which is " + rewindSeconds + " seconds ago"); |
| final AsyncLogReader reader = FutureUtils.result(dlm.openAsyncLogReader(rewindToTxId)); |
| final AtomicBoolean caughtup = new AtomicBoolean(false); |
| final FutureEventListener<LogRecordWithDLSN> readListener = new FutureEventListener<LogRecordWithDLSN>() { |
| @Override |
| public void onFailure(Throwable cause) { |
| System.err.println("Encountered error on reading records from stream " + dlm.getStreamName()); |
| cause.printStackTrace(System.err); |
| keepAliveLatch.countDown(); |
| } |
| |
| @Override |
| public void onSuccess(LogRecordWithDLSN record) { |
| System.out.println("Received record " + record.getDlsn()); |
| System.out.println("\"\"\""); |
| System.out.println(new String(record.getPayload(), UTF_8)); |
| System.out.println("\"\"\""); |
| |
| long diffInMilliseconds = System.currentTimeMillis() - record.getTransactionId(); |
| |
| if (!caughtup.get() && diffInMilliseconds < 2000) { |
| System.out.println("Reader caught with latest data"); |
| caughtup.set(true); |
| } |
| |
| reader.readNext().whenComplete(this); |
| } |
| }; |
| reader.readNext().whenComplete(readListener); |
| |
| keepAliveLatch.await(); |
| FutureUtils.result(reader.asyncClose(), 5, TimeUnit.SECONDS); |
| } |
| |
| } |