[cloud native] use of Nacos taskmanager task management

1、 Task management class

because Nacos This is used in many places in TaskManager, So we need to know what this class is for , It will not be difficult to read the source code later ;

Say first conclusion :

TaskManager

  It can be regarded as a set of tasks to be executed , Used to handle tasks that must be performed successfully   Single threaded processing of tasks , Ensure that the task is successfully handled ;  If the execution fails , The task will be put back into the collection for the next consumption ;

AbstractTask

AbstractTask

It's an abstract class , All tasks that need to be executed continue with this class ;  This class mainly provides the data and methods needed to perform tasks ; for example

   /*  The interval between two processes of a task , In milliseconds */
    private long taskInterval;
    /* The last time the task was processed , In milliseconds */
    private long lastProcessTime;
/* TaskManager  Determine whether you need to deal with this Task, Subclasses can Override This function implements its own logic
     */
    public boolean shouldProcess() {
        return (System.currentTimeMillis() - this.lastProcessTime >= this.taskInterval);
    }


TaskProcessor Task processor

TaskProcessor

  Is the task processor interface , It has a way

boolean process(String taskType, AbstractTask task);


Used to execute the corresponding AbstractTask The task class ;  Different types of tasks , You can implement your own execution task logic ;

TaskManager Task management class

TaskManager

  It is a task management class ; There are two properties in it to save the tasks to be consumed AbstractTask, And task execution TaskProcessor;

/** Tasks to be consumed AbstractTask**/
private&nbsp;final&nbsp;ConcurrentHashMap<String,&nbsp;AbstractTask>&nbsp;tasks&nbsp;=&nbsp;new&nbsp;ConcurrentHashMap<String,&nbsp;AbstractTask>();
/** Mission AbstractTask Corresponding task executor TaskProcessor**/
&nbsp;private&nbsp;final&nbsp;ConcurrentHashMap<String,&nbsp;TaskProcessor>&nbsp;taskProcessors&nbsp;=new&nbsp;ConcurrentHashMap<String,&nbsp;TaskProcessor>();


If taskProcessors No corresponding task executor was found in , Then it has a default actuator that will execute

 /** Default actuator **/
 private TaskProcessor defaultTaskProcessor;


2、 Use cases

Nacos

An important function of the configuration center module is , During initialization and every other period of time, all data will be stored in the database

Dump

To disk ;

Dump

It is a task class

AbstractTask

;  We said that above

AbstractTask

It is an information bearing object , Mainly for

TaskProcessor

Provide the data required for execution ; Let's see. DumpTask;

DumpTask

DumpTask Defines some of its own properties ;  Look at other examples

DumpAllTask

、

DumpAllBetaTask

These two task classes only define TASK_ID Since there are

DumpTask

The task class , There must be a corresponding task processor class

DumpProcessor

;

DumpProcessor

DumpProcessor

  yes DumpTask The executor of the task ; Methods in actuators

public boolean process(String taskType, AbstractTask task)


The code is too long to be analyzed here , Its main operation is

Save the configuration file to the local disk , And cache md5

See the article for details

【Nacos Configuration management of source code   Four 】DumpService How to complete the configuration file Dump To disk

Corresponding

DumpAllTask

、

DumpAllBetaTask

  The task executors of the task are

DumpAllProcessor

、

DumpAllBetaProcessor

3、DumpAllTask Where the task triggers execution

It's on it DumpAllTask The definition and DumpAllTaskProcessor Definition of actuator ; How is it triggered after it is defined ？

DumpService initialization Dump Configuration information

This class is specialized in Dump Service class of configuration information ; As mentioned above DumpAll It is here that is called ; Let's take a look at his main methods ;

    @PostConstruct
    public void init() {
        DumpAllProcessor dumpAllProcessor = new DumpAllProcessor(this);
      /** stay new This TaskManager Class time , A thread dedicated to the task has already started , But there is no task at this time Task Add in **/
       dumpAllTaskMgr = new TaskManager( "com.alibaba.nacos.server.DumpAllTaskManager");
dumpAllTaskMgr.setDefaultTaskProcessor(dumpAllProcessor);
      Runnable dumpAll = new Runnable() {
            @Override
            public void run() {
dumpAllTaskMgr.addTask(DumpAllTask.TASK_ID, new DumpAllTask());
            }
        };
            /** Every time 10 Once per minute DumpAll operation **/
      TimerTaskService.scheduleWithFixedDelay(dumpAll, initialDelay, DUMP_ALL_INTERVAL_IN_MINUTE,
                TimeUnit.MINUTES);
    }


DumpService This is called back during initialization init Method ;1. First new One. DumpAllProcessor actuator ;2. Again new  One. TaskManager Task manager ; stay new This task manager , A thread will be started to execute all the tasks to be executed ; It's just that no tasks have been added at this time ;3. Set the default executor of this task manager to DumpAllProcessor;4. Every ten minutes TaskManager Add a DumpAllTask The task of ; Once added, it will be TaskManager Thread in

processingThread

perform process Method ;