[PIG-1478] Add progress notification listener to PigRunner API

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.8.0
• Hadoop Flags: Reviewed
• Assignee: Richard Ding
• Reporter: Richard Ding
• Created: 01/Jul/10 20:20
• Updated: 17/Dec/10 22:44
• Resolved: 21/Jul/10 17:46

Description

PIG-1333 added PigRunner API to allow Pig users and tools to get a status/stats object back after executing a Pig script. The new API, however, is synchronous (blocking). It's known that a Pig script can spawn tens (even hundreds) MR jobs and take hours to complete. Therefore it'll be nice to give progress feedback to the callers during the execution.

The proposal is to add an optional parameter to the API:

public abstract class PigRunner {
    public static PigStats run(String[] args, PigProgressNotificationListener listener) {...}
}

The new listener is defined as following:

package org.apache.pig.tools.pigstats;

public interface PigProgressNotificationListener extends java.util.EventListener {
    // just before the launch of MR jobs for the script
    public void LaunchStartedNotification(int numJobsToLaunch);
    // number of jobs submitted in a batch
    public void jobsSubmittedNotification(int numJobsSubmitted);
    // a job is started
    public void jobStartedNotification(String assignedJobId);
    // a job is completed successfully
    public void jobFinishedNotification(JobStats jobStats);
    // a job is failed
    public void jobFailedNotification(JobStats jobStats);
    // a user output is completed successfully
    public void outputCompletedNotification(OutputStats outputStats);
    // updates the progress as percentage
    public void progressUpdatedNotification(int progress);
    // the script execution is done
    public void launchCompletedNotification(int numJobsSucceeded);
}

Any thoughts?