Storm源码分析Topology SubmitClient

1 Storm Client

最开始使用storm命令来启动topology, 如下

storm jar storm-starter-0.0.1-SNAPSHOT-standalone.jar storm.starter.WordCountTopology

这个storm命令是用python实现的, 看看其中的jar函数, 很简单, 调用exec_storm_class, 其中jvmtype="-client"
而exec_storm_class其实就是拼出一条java执行命令, 然后用os.system(command)去执行, 为何用Python写, 简单? 可以直接使用storm命令?
这儿的klass就是topology类, 所以java命令只是调用Topology类的main函数

def jar(jarfile, klass, *args):
    """Syntax: [storm jar topology-jar-path class ...]

Runs the main method of class with the specified arguments.
The storm jars and configs in ~/.storm are put on the classpath.
The process is configured so that StormSubmitter
(http://nathanmarz.github.com/storm/doc/backtype/storm/StormSubmitter.html)
will upload the jar at topology-jar-path when the topology is submitted.
"""
    exec_storm_class(
        klass,
        jvmtype="-client",
        extrajars=[jarfile, CONF_DIR, STORM_DIR + "/bin"],
        args=args,
        childopts="-Dstorm.jar=" + jarfile)

def exec_storm_class(klass, jvmtype="-server", childopts="", extrajars=[], args=[]):
    nativepath = confvalue("java.library.path", extrajars)
    args_str = " ".join(map(lambda s: "\"" + s + "\"", args))
    command = "java" + jvmtype + " -Dstorm.home=" + STORM_DIR + " " + get_config_opts() + " -Djava.library.path=" + nativepath + " " + childopts + " -cp" + get_classpath(extrajars) + " " + klass + " " + args_str
    print "Running:" + command
    os.system(command)

直接看看WordCountTopology例子的main函数都执行什么?

除了定义topology, 最终会调用StormSubmitter.submitTopology(args[0], conf, builder.createTopology()), 来提交topology

    public static void main(String[] args) throws Exception {        
        TopologyBuilder builder = new TopologyBuilder();        
        builder.setSpout("spout", new RandomSentenceSpout(), 5);        
        builder.setBolt("split", new SplitSentence(), 8)
                 .shuffleGrouping("spout");
        builder.setBolt("count", new WordCount(), 12)
                 .fieldsGrouping("split", new Fields("word"));

        Config conf = new Config();
        conf.setDebug(true);
      
        if(args!=null && args.length > 0) {
            conf.setNumWorkers(3);            
            StormSubmitter.submitTopology(args[0], conf, builder.createTopology());
        } else {        
            conf.setMaxTaskParallelism(3);
            LocalCluster cluster = new LocalCluster();
            cluster.submitTopology("word-count", conf, builder.createTopology());   
            Thread.sleep(10000);
            cluster.shutdown();
        }
    }

StormSubmitter

直接看看submitTopology,
1. 配置参数
   把命令行参数放在stormConf, 从conf/storm.yaml读取配置参数到conf, 再把stormConf也put到conf, 可见命令行参数的优先级更高
   将stormConf转化为Json, 因为这个配置是要发送到服务器的

2. Submit Jar
    StormSubmitter的本质是个Thrift Client, 而Nimbus则是Thrift Server, 所以所有的操作都是通过Thrift RPC来完成, Thrift参考Thrift, Storm-源码分析- Thrift的使用
    先判断topologyNameExists, 通过Thrift client得到现在运行的topology的状况, 并check
    然后Submit Jar, 通过底下三步         
    client.getClient().beginFileUpload();
    client.getClient().uploadChunk(uploadLocation, ByteBuffer.wrap(toSubmit));
    client.getClient().finishFileUpload(uploadLocation);
    把数据通过RPC发过去, 具体怎么存是nimbus自己的逻辑的事...

3. Submit Topology
    很简单只是简单的调用RPC
    client.getClient().submitTopologyWithOpts(name, submittedJar, serConf, topology, opts);

    /**
     * Submits a topology to run on the cluster. A topology runs forever or until 
     * explicitly killed.
     *
     *
     * @param name the name of the storm.
     * @param stormConf the topology-specific configuration. See {@link Config}. 
     * @param topology the processing to execute.
     * @param options to manipulate the starting of the topology
     * @throws AlreadyAliveException if a topology with this name is already running
     * @throws InvalidTopologyException if an invalid topology was submitted
     */
    public static void submitTopology(String name, Map stormConf, StormTopology topology, SubmitOptions opts) throws AlreadyAliveException, InvalidTopologyException {
        if(!Utils.isValidConf(stormConf)) {
            throw new IllegalArgumentException("Storm conf is not valid. Must be json-serializable");
        }
        stormConf = new HashMap(stormConf);
        stormConf.putAll(Utils.readCommandLineOpts());
        Map conf = Utils.readStormConfig();
        conf.putAll(stormConf);
        try {
            String serConf = JSONValue.toJSONString(stormConf);
            if(localNimbus!=null) {
                LOG.info("Submitting topology " + name + " in local mode");
                localNimbus.submitTopology(name, null, serConf, topology);
            } else {
                NimbusClient client = NimbusClient.getConfiguredClient(conf);
                if(topologyNameExists(conf, name)) {
                    throw new RuntimeException("Topology with name `" + name + "` already exists on cluster");
                }
                submitJar(conf);
                try {
                    LOG.info("Submitting topology " +  name + " in distributed mode with conf " + serConf);
                    if(opts!=null) {
                        client.getClient().submitTopologyWithOpts(name, submittedJar, serConf, topology, opts);                    
                    } else {
                        // this is for backwards compatibility
                        client.getClient().submitTopology(name, submittedJar, serConf, topology);                                            
                    }
                } catch(InvalidTopologyException e) {
                    LOG.warn("Topology submission exception", e);
                    throw e;
                } catch(AlreadyAliveException e) {
                    LOG.warn("Topology already alive exception", e);
                    throw e;
                } finally {
                    client.close();
                }
            }
            LOG.info("Finished submitting topology: " +  name);
        } catch(TException e) {
            throw new RuntimeException(e);
        }
    }