聊聊storm的tickTuple

序

本文主要研究一下storm的tickTuple

实例

TickWordCountBolt

public class TickWordCountBolt extends BaseBasicBolt {

    private static final Logger LOGGER = LoggerFactory.getLogger(TickWordCountBolt.class);

    Map counts = new HashMap();

    @Override
    public Map getComponentConfiguration() {
        Config conf = new Config();
        conf.put(Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS, 10);
        return conf;
    }

    @Override
    public void execute(Tuple input, BasicOutputCollector collector) {
        if(TupleUtils.isTick(input)){
            //execute tick logic
            LOGGER.info("execute tick tuple, emit and clear counts");
            counts.entrySet().stream()
                    .forEach(entry -> collector.emit(new Values(entry.getKey(), entry.getValue())));
            counts.clear();
        }else{
            String word = input.getString(0);
            Integer count = counts.get(word);
            if (count == null) count = 0;
            count++;
            counts.put(word, count);
        }
    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(new Fields("word", "count"));
    }
}

• 使用tick的话，在execute方法里头要自己判断tuple类型，然后执行相应处理
• 这里实例是重写getComponentConfiguration方法，直接new了一个conf，设置了Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS参数

tickTopology

    @Test
    public void testTickTuple() throws InvalidTopologyException, AuthorizationException, AlreadyAliveException {
        TopologyBuilder builder = new TopologyBuilder();
        //并发度10
        builder.setSpout("spout", new TestWordSpout(), 10);
        builder.setBolt("count", new TickWordCountBolt(), 5)
//                .addConfiguration(Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS, 3)
                .fieldsGrouping("spout", new Fields("word"));
        builder.setBolt("print", new PrintBolt(), 1)
                .shuffleGrouping("count");
        SubmitHelper.submitRemote("tickDemo",builder);
    }

• 除了重写getComponentConfiguration方法配置Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS参数外，还可以在TopologyBuilder.setBolt之后调用addConfiguration方法在配置，这个配置会覆盖getComponentConfiguration方法的配置
• 另外除了在bolt上配置，还可以在StormSubmitter.submitTopology时，对传入的conf配置Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS参数，不过这个配置是全局的，作用于整个topology的所有bolt；当出现既有全局配置，又有bolt自己的配置时，作用范围小的优先。

源码解析

TupleUtils.isTick

storm-2.0.0/storm-client/src/jvm/org/apache/storm/utils/TupleUtils.java

    public static boolean isTick(Tuple tuple) {
        return tuple != null
               && Constants.SYSTEM_COMPONENT_ID.equals(tuple.getSourceComponent())
               && Constants.SYSTEM_TICK_STREAM_ID.equals(tuple.getSourceStreamId());
    }

• isTick是根据tuple的sourceComponent以及sourceStreamId来判断

TopologyBuilder.setBolt

storm-2.0.0/storm-client/src/jvm/org/apache/storm/topology/TopologyBuilder.java

    /**
     * Define a new bolt in this topology with the specified amount of parallelism.
     *
     * @param id               the id of this component. This id is referenced by other components that want to consume this bolt's
     *                         outputs.
     * @param bolt             the bolt
     * @param parallelism_hint the number of tasks that should be assigned to execute this bolt. Each task will run on a thread in a process
     *                         somewhere around the cluster.
     * @return use the returned object to declare the inputs to this component
     *
     * @throws IllegalArgumentException if {@code parallelism_hint} is not positive
     */
    public BoltDeclarer setBolt(String id, IRichBolt bolt, Number parallelism_hint) throws IllegalArgumentException {
        validateUnusedId(id);
        initCommon(id, bolt, parallelism_hint);
        _bolts.put(id, bolt);
        return new BoltGetter(id);
    }

    private void initCommon(String id, IComponent component, Number parallelism) throws IllegalArgumentException {
        ComponentCommon common = new ComponentCommon();
        common.set_inputs(new HashMap());
        if (parallelism != null) {
            int dop = parallelism.intValue();
            if (dop < 1) {
                throw new IllegalArgumentException("Parallelism must be positive.");
            }
            common.set_parallelism_hint(dop);
        }
        Map conf = component.getComponentConfiguration();
        if (conf != null) {
            common.set_json_conf(JSONValue.toJSONString(conf));
        }
        commons.put(id, common);
    }

• setBolt的时候调用了initCommon，这里调用了bolt的getComponentConfiguration，将其配置写入到commons

BoltGetter.addConfiguration

storm-2.0.0/storm-client/src/jvm/org/apache/storm/topology/TopologyBuilder.java

    protected class BoltGetter extends ConfigGetter implements BoltDeclarer {
        //......
    }

• addConfiguration方法继承自BaseConfigurationDeclarer

BaseConfigurationDeclarer

storm-2.0.0/storm-client/src/jvm/org/apache/storm/topology/BaseConfigurationDeclarer.java

public abstract class BaseConfigurationDeclarer implements ComponentConfigurationDeclarer {
    @Override
    public T addConfiguration(String config, Object value) {
        Map configMap = new HashMap<>();
        configMap.put(config, value);
        return addConfigurations(configMap);
    }
    //......
}

• 这里新建一个map，然后调用子类的addConfigurations，这里子类为ConfigGetter

ConfigGetter.addConfigurations

    protected class ConfigGetter extends BaseConfigurationDeclarer {
        String id;

        public ConfigGetter(String id) {
            this.id = id;
        }

        @SuppressWarnings("unchecked")
        @Override
        public T addConfigurations(Map conf) {
            if (conf != null) {
                if (conf.containsKey(Config.TOPOLOGY_KRYO_REGISTER)) {
                    throw new IllegalArgumentException("Cannot set serializations for a component using fluent API");
                }
                if (!conf.isEmpty()) {
                    String currConf = commons.get(id).get_json_conf();
                    commons.get(id).set_json_conf(mergeIntoJson(parseJson(currConf), conf));
                }
            }
            return (T) this;
        }
        //......
    }

    private static String mergeIntoJson(Map into, Map newMap) {
        Map res = new HashMap<>(into);
        res.putAll(newMap);
        return JSONValue.toJSONString(res);
    }

• 可以看到这里从common获取配置，然后将自己的配置合并到component自身的配置中，也就是说addConfiguration的配置项会覆盖bolt在getComponentConfiguration方法中的配置

Executor.normalizedComponentConf

storm-2.0.0/storm-client/src/jvm/org/apache/storm/executor/Executor.java

    private Map normalizedComponentConf(
        Map topoConf, WorkerTopologyContext topologyContext, String componentId) {
        List keysToRemove = retrieveAllConfigKeys();
        keysToRemove.remove(Config.TOPOLOGY_DEBUG);
        keysToRemove.remove(Config.TOPOLOGY_MAX_SPOUT_PENDING);
        keysToRemove.remove(Config.TOPOLOGY_MAX_TASK_PARALLELISM);
        keysToRemove.remove(Config.TOPOLOGY_TRANSACTIONAL_ID);
        keysToRemove.remove(Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS);
        keysToRemove.remove(Config.TOPOLOGY_SLEEP_SPOUT_WAIT_STRATEGY_TIME_MS);
        keysToRemove.remove(Config.TOPOLOGY_SPOUT_WAIT_STRATEGY);
        keysToRemove.remove(Config.TOPOLOGY_BOLTS_WINDOW_LENGTH_COUNT);
        keysToRemove.remove(Config.TOPOLOGY_BOLTS_WINDOW_LENGTH_DURATION_MS);
        keysToRemove.remove(Config.TOPOLOGY_BOLTS_SLIDING_INTERVAL_COUNT);
        keysToRemove.remove(Config.TOPOLOGY_BOLTS_SLIDING_INTERVAL_DURATION_MS);
        keysToRemove.remove(Config.TOPOLOGY_BOLTS_TUPLE_TIMESTAMP_MAX_LAG_MS);
        keysToRemove.remove(Config.TOPOLOGY_BOLTS_MESSAGE_ID_FIELD_NAME);
        keysToRemove.remove(Config.TOPOLOGY_STATE_PROVIDER);
        keysToRemove.remove(Config.TOPOLOGY_STATE_PROVIDER_CONFIG);
        keysToRemove.remove(Config.TOPOLOGY_BOLTS_LATE_TUPLE_STREAM);

        Map componentConf;
        String specJsonConf = topologyContext.getComponentCommon(componentId).get_json_conf();
        if (specJsonConf != null) {
            try {
                componentConf = (Map) JSONValue.parseWithException(specJsonConf);
            } catch (ParseException e) {
                throw new RuntimeException(e);
            }
            for (Object p : keysToRemove) {
                componentConf.remove(p);
            }
        } else {
            componentConf = new HashMap<>();
        }

        Map ret = new HashMap<>();
        ret.putAll(topoConf);
        ret.putAll(componentConf);

        return ret;
    }

• Executor在构造器里头会调用normalizedComponentConf合并一下配置
• 对于componentConf移除掉topology的部分配置项，然后对返回值，先putAll(topoConf)再putAll(componentConf)，可以看到如果都有配置Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS的话，componentConf的会覆盖掉topoConf的配置。

Executor.setupTicks

storm-2.0.0/storm-client/src/jvm/org/apache/storm/executor/Executor.java

    protected void setupTicks(boolean isSpout) {
        final Integer tickTimeSecs = ObjectReader.getInt(topoConf.get(Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS), null);
        if (tickTimeSecs != null) {
            boolean enableMessageTimeout = (Boolean) topoConf.get(Config.TOPOLOGY_ENABLE_MESSAGE_TIMEOUTS);
            if ((!Acker.ACKER_COMPONENT_ID.equals(componentId) && Utils.isSystemId(componentId))
                || (!enableMessageTimeout && isSpout)) {
                LOG.info("Timeouts disabled for executor {}:{}", componentId, executorId);
            } else {
                StormTimer timerTask = workerData.getUserTimer();
                timerTask.scheduleRecurring(tickTimeSecs, tickTimeSecs,
                                            () -> {
                                                TupleImpl tuple = new TupleImpl(workerTopologyContext, new Values(tickTimeSecs),
                                                                                Constants.SYSTEM_COMPONENT_ID,
                                                                                (int) Constants.SYSTEM_TASK_ID,
                                                                                Constants.SYSTEM_TICK_STREAM_ID);
                                                AddressedTuple tickTuple = new AddressedTuple(AddressedTuple.BROADCAST_DEST, tuple);
                                                try {
                                                    receiveQueue.publish(tickTuple);
                                                    receiveQueue.flush(); // avoid buffering
                                                } catch (InterruptedException e) {
                                                    LOG.warn("Thread interrupted when emitting tick tuple. Setting interrupt flag.");
                                                    Thread.currentThread().interrupt();
                                                    return;
                                                }
                                            }
                );
            }
        }
    }

• 这里的topoConf是topoConf与componentConf合并之后的配置，对满足条件的component设置timerTask
• 可以看到这里new的TupleImpl的srcComponent设置为Constants.SYSTEM_COMPONENT_ID(__system)，taskId设置为Constants.SYSTEM_TASK_ID(-1)，streamId设置为Constants.SYSTEM_TICK_STREAM_ID(__tick)
• timerTask在调度的时候调用JCQueue(receiveQueue).publish(tickTuple)

JCQueue.publish

    private final DirectInserter directInserter = new DirectInserter(this);

    /**
     * Blocking call. Retries till it can successfully publish the obj. Can be interrupted via Thread.interrupt().
     */
    public void publish(Object obj) throws InterruptedException {
        Inserter inserter = getInserter();
        inserter.publish(obj);
    }

    private Inserter getInserter() {
        Inserter inserter;
        if (producerBatchSz > 1) {
            inserter = thdLocalBatcher.get();
            if (inserter == null) {
                BatchInserter b = new BatchInserter(this, producerBatchSz);
                inserter = b;
                thdLocalBatcher.set(b);
            }
        } else {
            inserter = directInserter;
        }
        return inserter;
    }

    private static class DirectInserter implements Inserter {
        private JCQueue q;

        public DirectInserter(JCQueue q) {
            this.q = q;
        }

        /**
         * Blocking call, that can be interrupted via Thread.interrupt
         */
        @Override
        public void publish(Object obj) throws InterruptedException {
            boolean inserted = q.tryPublishInternal(obj);
            int idleCount = 0;
            while (!inserted) {
                q.metrics.notifyInsertFailure();
                if (idleCount == 0) { // check avoids multiple log msgs when in a idle loop
                    LOG.debug("Experiencing Back Pressure on recvQueue: '{}'. Entering BackPressure Wait", q.getName());
                }

                idleCount = q.backPressureWaitStrategy.idle(idleCount);
                if (Thread.interrupted()) {
                    throw new InterruptedException();
                }
                inserted = q.tryPublishInternal(obj);
            }

        }
        //......
    }    

    // Non Blocking. returns true/false indicating success/failure. Fails if full.
    private boolean tryPublishInternal(Object obj) {
        if (recvQueue.offer(obj)) {
            metrics.notifyArrivals(1);
            return true;
        }
        return false;
    }

• JCQueue.publish的时候调用inserter.publish，这里inserter可能是BatchInserter或DirectInserter，这里看一下DirectInserter的publish方法
• DirectInserter的publish方法调用了JCQueue.tryPublishInternal，而该方法调用的是recvQueue.offer(obj)，放入到recvQueue队列

JCQueue.consume

storm-2.0.0/storm-client/src/jvm/org/apache/storm/utils/JCQueue.java

    /**
     * Non blocking. Returns immediately if Q is empty. Runs till Q is empty OR exitCond.keepRunning() return false. Returns number of
     * elements consumed from Q
     */
    public int consume(JCQueue.Consumer consumer, ExitCondition exitCond) {
        try {
            return consumeImpl(consumer, exitCond);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Non blocking. Returns immediately if Q is empty. Returns number of elements consumed from Q
     *
     * @param consumer
     * @param exitCond
     */
    private int consumeImpl(Consumer consumer, ExitCondition exitCond) throws InterruptedException {
        int drainCount = 0;
        while (exitCond.keepRunning()) {
            Object tuple = recvQueue.poll();
            if (tuple == null) {
                break;
            }
            consumer.accept(tuple);
            ++drainCount;
        }

        int overflowDrainCount = 0;
        int limit = overflowQ.size();
        while (exitCond.keepRunning() && (overflowDrainCount < limit)) { // 2nd cond prevents staying stuck with consuming overflow
            Object tuple = overflowQ.poll();
            ++overflowDrainCount;
            consumer.accept(tuple);
        }
        int total = drainCount + overflowDrainCount;
        if (total > 0) {
            consumer.flush();
        }
        return total;
    }

• 在聊聊storm worker的executor与task这篇文章我们有看到executor的asyncLoop主要是调用Executor.call().call()方法，对于BoltExecutor.call则是调用JCQueue.consume方法，该方法调用的是recvQueue.poll()
• 可以看到tickTuple与bolt的业务tuple是共用一个队列的

小结

• 关于tick的参数配置，有topology层面，有BoltDeclarer层面，也有bolt的getComponentConfiguration层面，三种方式，BoltDeclarer优先级最高，然后是bolt的getComponentConfiguration，最后是全局的topology层面的配置
• 对于tickTuple，采用的是StormTimer进行调度，调度的时候，往bolt的JCQueue的publish方法，具体是是调用recvQueue.offer(obj)；而executor的asycLoop调用Executor.call().call()方法，对于BoltExecutor.call则是调用JCQueue.consume方法，该方法调用的是recvQueue.poll()
• 因此可以看到timer只负责往队列发送tickTuple，至于触发的时间精度，不一定百分百精确，具体要看recvQueue队列的长度以及executor的消费能力

doc

• 关于Storm tick
• Tick tuples within Storm
• storm定时的三种方式及tick详解
• Apache Storm Design Pattern—Micro Batching
• 聊聊storm worker的executor与task