package org.ngbw.utils;

import org.apache.log4j.Logger;

import org.ngbw.sdk.Workbench;
import org.ngbw.sdk.database.ConnectionManager;
import org.ngbw.sdk.tool.TaskMonitor;


/**
 * Run periodically to poll remote resources and find out which jobs have
 * finished. We normally expect notification of job completion from a curl
 * command in the remote job scripts but if the job timesout or something else
 * goes wrong we may not be notified and need to poll.
 *
 * We check on all jobs that have a running_task table entry with status = SUBMITTED
 * and our submitter id. If the jobs is completed we set it's status to DONE.
 * The whole implementation is a static method in ProcessManager.
 */
public class CheckJobs
{
    private static final Logger logger = Logger.getLogger(CheckJobs.class);
    
    private static long m_poll_interval;
    
    private static String m_submitter;
    private static String m_default_submitter;
    
    
    
    public static void main ( String[] args )
    {
        try {
            Workbench wb = Workbench.getInstance();
            logger.debug("CHECK JOBS: Workbench initialized.");

            /*
             * TODO: If we don't use a connection pool checkJobs will crash every time it's
             * been sitting idle and the db connection goes stale - but we don't really need a pool
             * so find a better way to handle this. Currently we have a cron job that runs every
             * hour and starts it if it isn't running.
             *
             * The error is: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
             *
             * For the time being I think I will use a connection pool. Assuming we'll configure the pool
             * to start out very small (1 or 2 connections), then checkjobs will get one extra connection
             * at most.
             *
             *
             * //These 2 lines close the connection pool created in Workbench.getInstance() and
             * //open an unpooled connection source.
             * ConnectionManager.getConnectionSource().close();
             * ConnectionManager.setConnectionSource(new DriverConnectionSource());
             */
            
            m_default_submitter = wb.getProperties().getProperty("application.instance");
            String p = wb.getProperties().getProperty("checkJobs.poll.seconds");
            if (p == null) {
                throw new Exception("Missing workbench property: checkJobs.poll.seconds");
            }
            
            m_poll_interval = new Long(p);

            m_submitter = System.getProperty("submitter");
            if (m_submitter == null) {
                throw new Exception("Missing system property submitter");
            }
            logger.debug(String.format("Submitter=[%s], poll interval seconds [%d].", m_submitter, m_poll_interval));

            while (true) {
                TaskMonitor.checkJobs(m_submitter);
                Thread.sleep(m_poll_interval * 1000);
            }
        }
        catch ( Exception e ) {
            logger.error("", e);
            return;
        }
        finally {
            ConnectionManager.closeConnSourceQuietly();
        }
    }

}