How to terminate all tasks of a job chain

Scope

The following question has been asked:
- I need to know if there is a way to kill a task that is running, in a chosen moment. Example: at 12:30pm if any task that is running in a specific job chain, it will be immediately killed. Is there a way to do this? Can I make a scheduled job that can do this?
- Reference: https://sourceforge.net/p/jobscheduler/discussion/486122/thread/8de60ec3/
The solution outline includes a job chain that can be parameterized with orders for invididual points in time and a list of other job chains that should be terminated.

Solution

Download: kill_tasks.zip
- The files included with the archive should be usable with Windows and Unix systems.
Extract the archive to the ./config/live folder of your JobScheduler installation.
The archive will extract the files included to a folder kill_tasks, therefore all objects will be located in the ./config/live/kill_tasks folder.
You can store the sample files to a different folder, however, you would have to adjust the job_chains parameter from the kill_tasks order, see below.

Components

The test chain run_infinitely: this chain implements a test job that runs infinitely and can be started in multiple instances.
- One job run_infinitely is included that executes a number of ping commands to simulate a long running job. The job is configured to run in multiple instances if more than one order is active for the job chain.
- One order run_infinitely is included that starts the run_infinitely job chain. This order can be started manually by using JOC. Additional orders can be added by use of the Add Order context menu item with JOC.
The kill chain kill_tasks_in_job_chain: this chain implements the killing of tasks for any job chains.
- One job kill_tasks_in_job_chain is included that implements the JobScheduler <kill_task> XML command.
- One order kill_tasks_in_job_chain is included that starts the kill_tasks_in_job_chain job chain. This order can be started manually by using JOC.
  - This order makes use of two possible parameters:
    - job_chains: This parameters accepts one or multiple job chain paths.
      - Specify the full path including all folder names of the job chain that runs tasks that should be terminated.
      - Separate multiple job chain paths by use of a semicolon ";".
    - timeout: This parameter is available for Unix systems only and specifies a timeout in seconds.
      - The job kill_tasks_in_job_chain will first send a SIGTERM signal to any tasks of the run_infinitely job.
      - Should the run_infinitely job not be terminated after the timeout expires then a SIGKILL signal is sent to the tasks.
      - For Windows a SIGTERM signal is not available and therefore this parameter cannot be used or is used with a value 0.

Usage

Sample Usage
- Start the order run_infinitely for the job chain with the same name. Add an a additional order for the test chain, e.g. by using JOC with the Add Order context menu item.
  - The job run_infinitely from the job chain with the same name should be executed in two tasks (visible from JOC by clicking the job).
- Start the order kill_tasks from the kill_tasks_in_job_chain job chain.
  - The order will cause all tasks from the run_infinitely job chain to be terminated.
  - The order included with the above download archive specifies the path /issues/kill_tasks/run_infinitely for the job chain to be terminated. Modify this parameter to a different job chain path if your test job chain is located elsewhere.
Individual Usage
- Use any job chain path with the job_chains parameter of the kill_tasks_from_job_chain order.
- Specify a value for the timeout parameter to cause the tasks to be terminated to receive a SIGTERM signal first and a SIGKILL signal after timeout expiration. This functionality is available for Unix systems only.

Implementation

Job Chain: kill_tasks_in_job_chain

The job chain is straightforward, only one job is included:

job chain configuration: job configuration: kill_tasks_in_job_chain

<job_chain  title="Kill any tasks in a job chain" name="kill_tasks_in_job_chain">
    <job_chain_node  state="kill" job="kill_tasks_in_job_chain" next_state="success" error_state="error"/>
    <job_chain_node  state="success"/>
    <job_chain_node  state="error"/>
</job_chain>

Job: kill_tasks_in_job_chain

The job implements use of the JobScheduler API to retrieve information about running tasks and to kill tasks accordingly:

job configuration: kill_tasks_in_job_chain

function spooler_process() {
  var rc = true;

  // merge parameters from task and order
  var params = spooler.create_variable_set();
  params.merge( spooler_task.params );
  params.merge( spooler_task.order.params );

  // accept a list of colon separated job chain paths
  var jobChainPaths = params.value( "job_chains" ).split( ";" );
  var timeout = params.value( "timeout" );
  if (!timeout) { timeout = 0; }

  // traverse job chains as specified
  for (jobChainIndex in jobChainPaths) {
    var jobChainPath = jobChainPaths[jobChainIndex];
    if (!spooler.job_chain_exists( jobChainPath )) {
      spooler_log.error( ".. specified job chain does not exist: " + jobChainPath );
      rc = false;
      continue;
    }

    spooler_log.info( ".. traversing job chain: " + jobChainPath );
    var response = spooler.execute_xml( "<show_job_chain job_chain='" + jobChainPath + "' what='job_chain_jobs'/>" );
    var jobChainDOM = new Packages.sos.xml.SOSXMLXPath( new java.lang.StringBuffer( response ) );
    var jobChainNodes = jobChainDOM.selectNodeList( "/spooler/answer/job_chain/job_chain_node" );

    // traverse job chain nodes
    for( nodeIndex=0; nodeIndex<jobChainNodes.getLength(); nodeIndex++ ) {
      var jobChainNode = jobChainNodes.item(nodeIndex);
      var job = jobChainDOM.selectSingleNodeValue( jobChainNode, "@job" );
      if (job == null) {
        continue;
      }

      spooler_log.info( ".... job found: " + job );
      var response = spooler.execute_xml( "<show_job job='" + job + "' job_chain='" + jobChainPath + "' what='all'/>" );
      var jobDOM = new Packages.sos.xml.SOSXMLXPath( new java.lang.StringBuffer( response ) );
      var taskNodes = jobDOM.selectNodeList( "/spooler/answer/job/tasks/task" );

      for( taskNodeIndex=0; taskNodeIndex<taskNodes.getLength(); taskNodeIndex++ ) {
        var taskNode = taskNodes.item( taskNodeIndex );
        var taskID = jobDOM.selectSingleNodeValue( taskNode, "@id" );
        if (taskID == null) {
          continue;
        }

        spooler_log.info( "...... task found: " + taskID );
        if ( timeout > 0 ) {
          var command = "<kill_task id='" + taskID + "' job='" + job + "' immediately='yes' timeout='" + timeout + "'/>";
        } else {
          var command = "<kill_task id='" + taskID + "' job='" + job + "' immediately='yes'/>";
        }

        spooler_log.info( "........ kill task command: " + command );
        var response = spooler.execute_xml( command );
        var killTaskDOM = new Packages.sos.xml.SOSXMLXPath( new java.lang.StringBuffer(response) );
        var errorCode = killTaskDOM.selectSingleNodeValue( "//ERROR/@code" );
        var errorText = killTaskDOM.selectSingleNodeValue( "//ERROR/@text" );
        if ( errorCode || errorText ) {
          spooler_log.error( "........ kill task response: errorCode=" + errorCode + ", errorText=" + errorText );
          rc = false;
        }
      }
    }  
  }
  return rc;
}

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