| /** |
| * 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 com.datatorrent.contrib.nifi; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.apex.malhar.lib.wal.WindowDataManager; |
| import org.apache.nifi.remote.Transaction; |
| import org.apache.nifi.remote.TransferDirection; |
| import org.apache.nifi.remote.client.SiteToSiteClient; |
| import org.apache.nifi.remote.protocol.DataPacket; |
| |
| import com.datatorrent.api.Context; |
| import com.datatorrent.api.InputOperator; |
| import com.datatorrent.netlet.util.DTThrowable; |
| |
| /** |
| * This is the base implementation of a NiFi input operator. |
| * Subclasses should implement the methods which convert NiFi DataPackets to tuples and emit them. |
| * <p> |
| * Ports:<br> |
| * <b>Input</b>: No input port<br> |
| * <b>Output</b>: Can have any number of output ports<br> |
| * <br> |
| * Properties:<br> |
| * None<br> |
| * <br> |
| * Compile time checks:<br> |
| * Classes derived from this have to implement the abstract methods emitTuples(List<T> tuples) |
| * and createTuple(DataPacket dp)<br> |
| * <br> |
| * Run time checks:<br> |
| * None<br> |
| * <br> |
| * Benchmarks:<br> |
| * TBD<br> |
| * </p> |
| * |
| * @displayName Abstract NiFi Input |
| * @category Messaging |
| * @tags input operator |
| * |
| * @since 3.4.0 |
| */ |
| |
| public abstract class AbstractNiFiInputOperator<T> implements InputOperator |
| { |
| |
| private static final Logger LOGGER = LoggerFactory.getLogger(AbstractNiFiInputOperator.class); |
| |
| private transient SiteToSiteClient client; |
| private final SiteToSiteClient.Builder siteToSiteBuilder; |
| |
| private transient int operatorContextId; |
| private transient long currentWindowId; |
| private transient List<T> currentWindowTuples; |
| private transient List<T> recoveredTuples; |
| private final WindowDataManager windowDataManager; |
| |
| /** |
| * @param siteToSiteBuilder the builder for a NiFi SiteToSiteClient |
| * @param windowDataManager a WindowDataManager to save and load state for windows of tuples |
| */ |
| public AbstractNiFiInputOperator(final SiteToSiteClient.Builder siteToSiteBuilder, |
| final WindowDataManager windowDataManager) |
| { |
| this.siteToSiteBuilder = siteToSiteBuilder; |
| this.windowDataManager = windowDataManager; |
| } |
| |
| @Override |
| public void setup(Context.OperatorContext context) |
| { |
| this.client = siteToSiteBuilder.build(); |
| this.operatorContextId = context.getId(); |
| this.currentWindowTuples = new ArrayList<>(); |
| this.recoveredTuples = new ArrayList<>(); |
| this.windowDataManager.setup(context); |
| } |
| |
| @Override |
| public void beginWindow(long windowId) |
| { |
| currentWindowId = windowId; |
| |
| // if the current window is now less than the largest window, then we need to replay data |
| if (currentWindowId <= windowDataManager.getLargestCompletedWindow()) { |
| try { |
| List<T> recoveredData = (List<T>)this.windowDataManager.retrieve(windowId); |
| if (recoveredData == null) { |
| return; |
| } |
| |
| // if we recovered tuples then load them to be processed by next call to emitTuples() |
| recoveredTuples.addAll(recoveredData); |
| } catch (IOException e) { |
| DTThrowable.rethrow(e); |
| } |
| } |
| } |
| |
| @Override |
| public void emitTuples() |
| { |
| // if we have recovered tuples we must be replaying a previous window so emit them, |
| // clear the recovered list, and return until we have no more recovered data |
| if (recoveredTuples.size() > 0) { |
| emitTuples(recoveredTuples); |
| recoveredTuples.clear(); |
| return; |
| } |
| |
| // no recovered data so start a transaction and pull new data |
| try { |
| final Transaction transaction = client.createTransaction(TransferDirection.RECEIVE); |
| if (transaction == null) { |
| LOGGER.warn("A transaction could not be created, returning..."); |
| return; |
| } |
| |
| DataPacket dataPacket = transaction.receive(); |
| if (dataPacket == null) { |
| transaction.confirm(); |
| transaction.complete(); |
| LOGGER.debug("No data available to pull, returning and will try again..."); |
| return; |
| } |
| |
| // read all of the available data packets and convert to the given type |
| final List<T> tuples = new ArrayList<>(); |
| do { |
| tuples.add(createTuple(dataPacket)); |
| dataPacket = transaction.receive(); |
| } while (dataPacket != null); |
| |
| // confirm all of the expected data was received by comparing check-sums, does not complete the transaction |
| transaction.confirm(); |
| |
| // ensure we have the data saved before proceeding in case anything goes wrong |
| currentWindowTuples.addAll(tuples); |
| windowDataManager.save(currentWindowTuples, currentWindowId); |
| |
| // we now have the data saved so we can complete the transaction |
| transaction.complete(); |
| |
| // delegate to sub-classes to emit the tuples |
| emitTuples(tuples); |
| |
| } catch (IOException e) { |
| DTThrowable.rethrow(e); |
| } |
| } |
| |
| /** |
| * Provides mechanism for converting a DataPacket to the given type. |
| * |
| * @param dataPacket a DataPacket from the NiFi Site-To-Site client. |
| * @return the given type of tuple |
| */ |
| protected abstract T createTuple(final DataPacket dataPacket) throws IOException; |
| |
| /** |
| * Provided mechanism to emit the list of tuples for follow-on processing. |
| * |
| * @param tuples a list of tuples received from NiFi. |
| */ |
| protected abstract void emitTuples(final List<T> tuples); |
| |
| @Override |
| public void endWindow() |
| { |
| // save the final state of the window and clear the current window list |
| try { |
| windowDataManager.save(currentWindowTuples, currentWindowId); |
| } catch (IOException e) { |
| DTThrowable.rethrow(e); |
| } |
| currentWindowTuples.clear(); |
| } |
| |
| @Override |
| public void teardown() |
| { |
| LOGGER.debug("Tearing down operator..."); |
| windowDataManager.teardown(); |
| try { |
| client.close(); |
| } catch (IOException e) { |
| throw new RuntimeException("Error closing SiteToSiteClient", e); |
| } |
| } |
| |
| } |