Azkaban的Web Server源码探究系列14：创建Project

最新推荐文章于 2023-10-09 20:16:25 发布

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最新推荐文章于 2023-10-09 20:16:25 发布

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文章标签： python

原文链接：https://my.oschina.net/qiangzigege/blog/655499

本文分析了Azkaban中ProjectManagerServlet的工作原理，重点介绍了init方法中各组件的初始化过程以及doPost方法中对创建项目的处理流程。此外，还深入探讨了handleCreate方法内部实现，特别是如何通过数据库操作来完成新项目的创建。

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创建的图为：

通过抓包，可以分析出路径为：

POST /manager HTTP/1.1

所以，需要分析

root.addServlet(new ServletHolder(new ProjectManagerServlet()), "/manager");

分析ProjectManagerServlet

=================================================================================

1)init

@Override

public void init(ServletConfig config) throws ServletException {

super.init(config);

AzkabanWebServer server = (AzkabanWebServer) getApplication();

projectManager = server.getProjectManager();

executorManager = server.getExecutorManager();

scheduleManager = server.getScheduleManager();

userManager = server.getUserManager();

lockdownCreateProjects =

server.getServerProps().getBoolean(LOCKDOWN_CREATE_PROJECTS_KEY, false);

if (lockdownCreateProjects) {

logger.info("Creation of projects is locked down");

}

downloadBufferSize =

server.getServerProps().getInt(PROJECT_DOWNLOAD_BUFFER_SIZE_IN_BYTES,

8192);

logger.info("downloadBufferSize: " + downloadBufferSize);

}

比较简单，就不多说了。

2)doPost

@Override

protected void handlePost(HttpServletRequest req, HttpServletResponse resp,

Session session) throws ServletException, IOException {

//从这里开始

if (hasParam(req, "action")) {

String action = getParam(req, "action");

if (action.equals("create")) {//如果是创建Project

handleCreate(req, resp, session);

}

下面就需要去看handleCreate的代码。。。

========================================================================

private synchronized Project createNewProject(Connection connection,

String name, String description, User creator)

throws ProjectManagerException {

QueryRunner runner = new QueryRunner();

ProjectResultHandler handler = new ProjectResultHandler();

//查看是否存在

try {

List<Project> project =

runner

.query(connection,

ProjectResultHandler.SELECT_ACTIVE_PROJECT_BY_NAME, handler,

name);

if (!project.isEmpty()) {

throw new ProjectManagerException("Active project with name " + name

+ " already exists in db.");

}

} catch (SQLException e) {

logger.error(e);

throw new ProjectManagerException(

"Checking for existing project failed. " + name, e);

}

//执行插入语句

final String INSERT_PROJECT =

"INSERT INTO projects ( name, active, modified_time, create_time, version, last_modified_by, description, enc_type, settings_blob) values (?,?,?,?,?,?,?,?,?)";

// Insert project

try {

long time = System.currentTimeMillis();

int i =

runner.update(connection, INSERT_PROJECT, name, true, time, time,

null, creator.getUserId(), description,

defaultEncodingType.getNumVal(), null);

if (i == 0) {

throw new ProjectManagerException("No projects have been inserted.");

}

connection.commit();

} catch (SQLException e) {

logger.error(INSERT_PROJECT + " failed.");

try {

connection.rollback();

} catch (SQLException e1) {

e1.printStackTrace();

}

throw new ProjectManagerException(

"Insert project for existing project failed. " + name, e);

}

//顺利插入

// Do another query to grab and return the project.

Project project = null;

try {

List<Project> projects =

runner

.query(connection,

ProjectResultHandler.SELECT_ACTIVE_PROJECT_BY_NAME, handler,

name);

if (projects.isEmpty()) {

throw new ProjectManagerException("No active project with name " + name

+ " exists in db.");

} else if (projects.size() > 1) {

throw new ProjectManagerException("More than one active project "

+ name);

}

project = projects.get(0);

} catch (SQLException e) {

logger.error(e);

throw new ProjectManagerException(

"Checking for existing project failed. " + name, e);

}

//返回

return project;

}

当然，最后做了一个event 跟踪，

然后再返回给浏览器以下内容：

1032224350@qtp-808228639-2[1] print response

response = "{"path":"manager?project=adf","action":"redirect","status":"success"}"

搞定！

转载于:https://my.oschina.net/qiangzigege/blog/655499