Mesos源码分析(15): Test Executor的运行

Test Executor的代码在src/examples/test_executor.cpp中

 

1. int main(int argc, char** argv)
2. {
3.   TestExecutor executor;
4.   MesosExecutorDriver driver(&executor);
5.   return driver.run() == DRIVER_STOPPED ? 0 : 1;
6. }

 

Executor的运行主要依赖于MesosExecutorDriver作为封装，和mesos-slave进行通信。

 

MesosExecutorDriver的实现在src/exec/exec.cpp中

 

1. Status MesosExecutorDriver::run()
2. {
3.   Status status = start();
4.   return status != DRIVER_RUNNING ? status : join();
5. }

 

1. Status MesosExecutorDriver::start()
2. {
3.   synchronized (mutex) {
4.     if (status != DRIVER_NOT_STARTED) {
5.       return status;
6.     }
7.  
8.     // Set stream buffering mode to flush on newlines so that we
9.     // capture logs from user processes even when output is redirected
10.     // to a file.
11.     setvbuf(stdout, 0, _IOLBF, 0);
12.     setvbuf(stderr, 0, _IOLBF, 0);
13.  
14.     bool local;
15.  
16.     UPID slave;
17.     SlaveID slaveId;
18.     FrameworkID frameworkId;
19.     ExecutorID executorId;
20.     string workDirectory;
21.     bool checkpoint;
22.  
23.     Option<string> value;
24.     std::istringstream iss;
25.  
26.     // Check if this is local (for example, for testing).
27.     local = os::getenv("MESOS_LOCAL").isSome();
28.  
29.     // Get slave PID from environment.
30.     value = os::getenv("MESOS_SLAVE_PID");
31.     if (value.isNone()) {
32.       EXIT(EXIT_FAILURE)
33.         << "Expecting 'MESOS_SLAVE_PID' to be set in the environment";
34.     }
35.  
36.     slave = UPID(value.get());
37.     CHECK(slave) << "Cannot parse MESOS_SLAVE_PID '" << value.get() << "'";
38.  
39.     // Get slave ID from environment.
40.     value = os::getenv("MESOS_SLAVE_ID");
41.     if (value.isNone()) {
42.       EXIT(EXIT_FAILURE)
43.         << "Expecting 'MESOS_SLAVE_ID' to be set in the environment";
44.     }
45.     slaveId.set_value(value.get());
46.  
47.     // Get framework ID from environment.
48.     value = os::getenv("MESOS_FRAMEWORK_ID");
49.     if (value.isNone()) {
50.       EXIT(EXIT_FAILURE)
51.         << "Expecting 'MESOS_FRAMEWORK_ID' to be set in the environment";
52.     }
53.     frameworkId.set_value(value.get());
54.  
55.     // Get executor ID from environment.
56.     value = os::getenv("MESOS_EXECUTOR_ID");
57.     if (value.isNone()) {
58.       EXIT(EXIT_FAILURE)
59.         << "Expecting 'MESOS_EXECUTOR_ID' to be set in the environment";
60.     }
61.     executorId.set_value(value.get());
62.  
63.     // Get working directory from environment.
64.     value = os::getenv("MESOS_DIRECTORY");
65.     if (value.isNone()) {
66.       EXIT(EXIT_FAILURE)
67.         << "Expecting 'MESOS_DIRECTORY' to be set in the environment";
68.     }
69.     workDirectory = value.get();
70.  
71.     // Get checkpointing status from environment.
72.     value = os::getenv("MESOS_CHECKPOINT");
73.     checkpoint = ";
74.  
75.     Duration recoveryTimeout = RECOVERY_TIMEOUT;
76.  
77.     // Get the recovery timeout if checkpointing is enabled.
78.     if (checkpoint) {
79.       value = os::getenv("MESOS_RECOVERY_TIMEOUT");
80.  
81.       if (value.isSome()) {
82.         Try<Duration> _recoveryTimeout = Duration::parse(value.get());
83.  
84.         if (_recoveryTimeout.isError()) {
85.           EXIT(EXIT_FAILURE)
86.             << "Cannot parse MESOS_RECOVERY_TIMEOUT '" << value.get() << "': "
87.             << _recoveryTimeout.error();
88.         }
89.  
90.         recoveryTimeout = _recoveryTimeout.get();
91.       }
92.     }
93.  
94.     CHECK(process == NULL);
95.  
96.     process = new ExecutorProcess(
97.         slave,
98.         this,
99.         executor,
100.         slaveId,
101.         frameworkId,
102.         executorId,
103.         local,
104.         workDirectory,
105.         checkpoint,
106.         recoveryTimeout,
107.         &mutex,
108.         latch);
109.  
110.     spawn(process);
111.  
112.     return status = DRIVER_RUNNING;
113.   }
114. }

 

启动另一个线程ExecutorProcess，它的构造函数如下，注册了很多消息处理函数。

 

1. ExecutorProcess(const UPID& _slave,
2.                 MesosExecutorDriver* _driver,
3.                 Executor* _executor,
4.                 const SlaveID& _slaveId,
5.                 const FrameworkID& _frameworkId,
6.                 const ExecutorID& _executorId,
7.                 bool _local,
8.                 const
   string& _directory,
9.                 bool _checkpoint,
10.                 Duration _recoveryTimeout,
11.                 std::recursive_mutex* _mutex,
12.                 Latch* _latch)
13.   : ProcessBase(ID::generate("executor")),
14.     slave(_slave),
15.     driver(_driver),
16.     executor(_executor),
17.     slaveId(_slaveId),
18.     frameworkId(_frameworkId),
19.     executorId(_executorId),
20.     connected(false),
21.     connection(UUID::random()),
22.     local(_local),
23.     aborted(false),
24.     mutex(_mutex),
25.     latch(_latch),
26.     directory(_directory),
27.     checkpoint(_checkpoint),
28.     recoveryTimeout(_recoveryTimeout)
29. {
30.   LOG(INFO) << "Version: " << MESOS_VERSION;
31.  
32.   install<ExecutorRegisteredMessage>(
33.       &ExecutorProcess::registered,
34.       &ExecutorRegisteredMessage::executor_info,
35.       &ExecutorRegisteredMessage::framework_id,
36.       &ExecutorRegisteredMessage::framework_info,
37.       &ExecutorRegisteredMessage::slave_id,
38.       &ExecutorRegisteredMessage::slave_info);
39.  
40.   install<ExecutorReregisteredMessage>(
41.       &ExecutorProcess::reregistered,
42.       &ExecutorReregisteredMessage::slave_id,
43.       &ExecutorReregisteredMessage::slave_info);
44.  
45.   install<ReconnectExecutorMessage>(
46.       &ExecutorProcess::reconnect,
47.       &ReconnectExecutorMessage::slave_id);
48.  
49.   install<RunTaskMessage>(
50.       &ExecutorProcess::runTask,
51.       &RunTaskMessage::task);
52.  
53.   install<KillTaskMessage>(
54.       &ExecutorProcess::killTask,
55.       &KillTaskMessage::task_id);
56.  
57.   install<StatusUpdateAcknowledgementMessage>(
58.       &ExecutorProcess::statusUpdateAcknowledgement,
59.       &StatusUpdateAcknowledgementMessage::slave_id,
60.       &StatusUpdateAcknowledgementMessage::framework_id,
61.       &StatusUpdateAcknowledgementMessage::task_id,
62.       &StatusUpdateAcknowledgementMessage::uuid);
63.  
64.   install<FrameworkToExecutorMessage>(
65.       &ExecutorProcess::frameworkMessage,
66.       &FrameworkToExecutorMessage::slave_id,
67.       &FrameworkToExecutorMessage::framework_id,
68.       &FrameworkToExecutorMessage::executor_id,
69.       &FrameworkToExecutorMessage::data);
70.  
71.   install<ShutdownExecutorMessage>(
72.       &ExecutorProcess::shutdown);
73. }

 

在ExecutorProcess的initiailize的函数中，向mesos-slave发送消息进行注册。

1. virtual
   void initialize()
2. {
3.   VLOG(1) << "Executor started at: " << self()
4.           << " with pid " << getpid();
5.  
6.   link(slave);
7.  
8.   // Register with slave.
9.   RegisterExecutorMessage message;
10.   message.mutable_framework_id()->MergeFrom(frameworkId);
11.   message.mutable_executor_id()->MergeFrom(executorId);
12.   send(slave, message);
13. }

 

当Mesos-slave向TestExecutor发送RunTaskMessage消息的时候，ExecutorProcess调用runTask函数。

1. void runTask(const TaskInfo& task)
2. {
3.   if (aborted.load()) {
4.     VLOG(1) << "Ignoring run task message for task " << task.task_id()
5.             << " because the driver is aborted!";
6.     return;
7.   }
8.  
9.   CHECK(!tasks.contains(task.task_id()))
10.     << "Unexpected duplicate task " << task.task_id();
11.  
12.   tasks[task.task_id()] = task;
13.  
14.   VLOG(1) << "Executor asked to run task '" << task.task_id() << "'";
15.  
16.   Stopwatch stopwatch;
17.   if (FLAGS_v >= 1) {
18.     stopwatch.start();
19.   }
20.  
21.   executor->launchTask(driver, task);
22.  
23.   VLOG(1) << "Executor::launchTask took " << stopwatch.elapsed();
24. }

 

最终调用executor的launchTask

在src/examples/test_executor.cpp中

1. virtual
   void launchTask(ExecutorDriver* driver, const TaskInfo& task)
2. {
3.   cout << "Starting task " << task.task_id().value() << endl;
4.  
5.   TaskStatus status;
6.   status.mutable_task_id()->MergeFrom(task.task_id());
7.   status.set_state(TASK_RUNNING);
8.  
9.   driver->sendStatusUpdate(status);
10.  
11.   // This is where one would perform the requested task.
12.  
13.   cout << "Finishing task " << task.task_id().value() << endl;
14.  
15.   status.mutable_task_id()->MergeFrom(task.task_id());
16.   status.set_state(TASK_FINISHED);
17.  
18.   driver->sendStatusUpdate(status);
19. }