最近想借着调度系统这个项目来看看业界出色的调度系统的源码，如Oozie，Airflow目录如下，

Overview

Oozie是雅虎开源出来的一个出色的工作流，支持很多jobType，spark，email等。主要分为3个角色，

server，用于保持长链接，监听来自于client的jobSubmit，然后分发job到各个executor上去执行，执行结果展示在UI上
client，与用户打交道，用户在部署了client的机器上直接运行cmd，用来submit cmd，如kill，check，submit
shardlib(adaptor, executor)：真正的执行部件

Version

<groupId>org.apache.oozie</groupId>
<artifactId>oozie-main</artifactId>
<version>5.1.0-SNAPSHOT</version>

Latest Submission

Client

下面看看它的源码入口，

bash oozie -> org.apache.oozie.cli.OozieCLI -> run() -> processCommand()
e.g.: processCommand() -> jobCommand() -> KILL_OPTION -> wc.kill() -> new JobAction() -> call() -> createURL() -> JobAction.call(HttpURLConnection conn) （2个不同的call function，拼接URL，然后发送到server）
e.g.: oozie job -oozie http://localhost:11000/oozie -kill 14-20090525161321-oozie-joe (这句的oozie对应上句的oozie，即每次运行CommandLineTool命令都是java -cp了OozieCLI，只是每次的OozieCLI启动参数不同而已)

super("PUT", RestConstants.JOB, notEmpty(jobId, "jobId"), prepareParams(RestConstants.ACTION_PARAM, action));

public ClientCallable(String method, String collection, String resource, Map<String, String> params) {
    this(method, null, collection, resource, params);
}

public ClientCallable(String method, Long protocolVersion, String collection, String resource, Map<String, String> params) {
    this.method = method;
    this.protocolVersion = protocolVersion;
    this.collection = collection;
    this.resource = resource;
    this.params = params;
}

URL url = createURL(protocolVersion, collection, resource, params);

sb.append(getBaseURLForVersion(protocolVersion));

CLI

Server

源码入口，

bash oozied.sh -> oozie-jetty-server.sh -> org.apache.oozie.server.EmbeddedOozieServer
embeddedOozieServer.setup() -> oozieServletMapper.mapOozieServlets(); -> mapServlet(V0JobServlet.class, "/v0/job/*"); -> BaseJobServlet.doPut() -> embeddedOozieServer.join()
server hold till shutdown hook
e.g.: mapServlet(V0JobServlet.class, "/v0/job/*");, *号就是Client的jobId，v0就是protocolVersion，job是字符串常量"job"

URL Mapping

shardlib

源码入口，

servletHandler.addServlet(new ServletHolder(v1JobsServletName, new V1JobsServlet()));
EmbeddedOozieServer -> ServletMapper -> V1JobsServlet.submitJob().submitHttpJob() -> dagEngine.submitJob() -> submit.call() -> start(jobId) -> new StartXCommand(jobId).call() -> ...

将自定义的xxx.wf xml翻译成DAG，然后定时运行。

Actions Supported by Oozie

Oozie Source Code Main