| /** |
| * 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.heron.examples.streamlet; |
| |
| import java.io.Serializable; |
| import java.util.Arrays; |
| import java.util.List; |
| import java.util.concurrent.ThreadLocalRandom; |
| import java.util.logging.Logger; |
| |
| import org.apache.heron.examples.streamlet.utils.StreamletUtils; |
| import org.apache.heron.streamlet.Builder; |
| import org.apache.heron.streamlet.Config; |
| import org.apache.heron.streamlet.Runner; |
| import org.apache.heron.streamlet.Streamlet; |
| |
| /** |
| * This topology demonstrates how different streamlets can be united into one |
| * using union operations. Wire requests (customers asking to wire money) are |
| * created for three different bank branches. Each bank branch is a separate |
| * streamlet. In each branch's streamlet, the request amount is checked to make |
| * sure that no one requests a wire transfer of more than $500. Then, the |
| * wire request streamlets for all three branches are combined into one using a |
| * union operation. Each element in the unified streamlet then passes through a |
| * fraud detection filter that ensures that no "bad" customers are allowed to |
| * make requests. |
| */ |
| public final class WireRequestsTopology { |
| private WireRequestsTopology() { |
| } |
| |
| private static final Logger LOG = |
| Logger.getLogger(WireRequestsTopology.class.getName()); |
| |
| /** |
| * A list of current customers (some good, some bad). |
| */ |
| private static final List<String> CUSTOMERS = Arrays.asList( |
| "honest-tina", |
| "honest-jeff", |
| "scheming-dave", |
| "scheming-linda" |
| ); |
| |
| /** |
| * A list of bad customers whose requests should be rejected. |
| */ |
| private static final List<String> FRAUDULENT_CUSTOMERS = Arrays.asList( |
| "scheming-dave", |
| "scheming-linda" |
| ); |
| |
| /** |
| * The maximum allowable amount for transfers. Requests for more than this |
| * amount need to be rejected. |
| */ |
| private static final int MAX_ALLOWABLE_AMOUNT = 500; |
| |
| /** |
| * A POJO for wire requests. |
| */ |
| private static class WireRequest implements Serializable { |
| private static final long serialVersionUID = 1311441220738558016L; |
| private String customerId; |
| private int amount; |
| |
| WireRequest(long delay) { |
| // The pace at which requests are generated is throttled. Different |
| // throttles are applied to different bank branches. |
| StreamletUtils.sleep(delay); |
| this.customerId = StreamletUtils.randomFromList(CUSTOMERS); |
| this.amount = ThreadLocalRandom.current().nextInt(1000); |
| LOG.info(String.format("New wire request: %s", this)); |
| } |
| |
| String getCustomerId() { |
| return customerId; |
| } |
| |
| int getAmount() { |
| return amount; |
| } |
| |
| @Override |
| public String toString() { |
| return String.format("(customer: %s, amount: %d)", customerId, amount); |
| } |
| } |
| |
| /** |
| * Each request is checked to make sure that requests from untrustworthy customers |
| * are rejected. |
| */ |
| private static boolean fraudDetect(WireRequest request) { |
| String logMessage; |
| |
| boolean fraudulent = FRAUDULENT_CUSTOMERS.contains(request.getCustomerId()); |
| |
| if (fraudulent) { |
| logMessage = String.format("Rejected fraudulent customer %s", |
| request.getCustomerId()); |
| LOG.warning(logMessage); |
| } else { |
| logMessage = String.format("Accepted request for $%d from customer %s", |
| request.getAmount(), |
| request.getCustomerId()); |
| LOG.info(logMessage); |
| } |
| |
| return !fraudulent; |
| } |
| |
| /** |
| * Each request is checked to make sure that no one requests an amount over $500. |
| */ |
| private static boolean checkRequestAmount(WireRequest request) { |
| boolean sufficientBalance = request.getAmount() < MAX_ALLOWABLE_AMOUNT; |
| |
| if (!sufficientBalance) { |
| LOG.warning( |
| String.format("Rejected excessive request of $%d", |
| request.getAmount())); |
| } |
| |
| return sufficientBalance; |
| } |
| |
| /** |
| * All Heron topologies require a main function that defines the topology's behavior |
| * at runtime |
| */ |
| public static void main(String[] args) throws Exception { |
| Builder builder = Builder.newBuilder(); |
| |
| // Requests from the "quiet" bank branch (high throttling). |
| Streamlet<WireRequest> quietBranch = builder.newSource(() -> new WireRequest(20)) |
| .setNumPartitions(1) |
| .setName("quiet-branch-requests") |
| .filter(WireRequestsTopology::checkRequestAmount) |
| .setName("quiet-branch-check-balance"); |
| |
| // Requests from the "medium" bank branch (medium throttling). |
| Streamlet<WireRequest> mediumBranch = builder.newSource(() -> new WireRequest(10)) |
| .setNumPartitions(2) |
| .setName("medium-branch-requests") |
| .filter(WireRequestsTopology::checkRequestAmount) |
| .setName("medium-branch-check-balance"); |
| |
| // Requests from the "busy" bank branch (low throttling). |
| Streamlet<WireRequest> busyBranch = builder.newSource(() -> new WireRequest(5)) |
| .setNumPartitions(4) |
| .setName("busy-branch-requests") |
| .filter(WireRequestsTopology::checkRequestAmount) |
| .setName("busy-branch-check-balance"); |
| |
| // Here, the streamlets for the three bank branches are united into one. The fraud |
| // detection filter then operates on that unified streamlet. |
| quietBranch |
| .union(mediumBranch) |
| .setNumPartitions(2) |
| .setName("union-1") |
| .union(busyBranch) |
| .setName("union-2") |
| .setNumPartitions(4) |
| .filter(WireRequestsTopology::fraudDetect) |
| .setName("all-branches-fraud-detect") |
| .log(); |
| |
| Config config = Config.newBuilder() |
| .setDeliverySemantics(Config.DeliverySemantics.EFFECTIVELY_ONCE) |
| .setNumContainers(2) |
| .build(); |
| |
| // Fetches the topology name from the first command-line argument |
| String topologyName = StreamletUtils.getTopologyName(args); |
| |
| // Finally, the processing graph and configuration are passed to the Runner, which converts |
| // the graph into a Heron topology that can be run in a Heron cluster. |
| new Runner().run(topologyName, config, builder); |
| } |
| } |