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    Comment: Published by Scroll Versions from this space and version 7.0-2

    Overview

    Universal callbacks are operations which are automatically attached to every job that is submitted. These are installed by a site administrator either on the Supervisor's local disk or on a file system which is accessible by the supervisor service.

    Setting Up Universal Callbacks

    To set up Universal Callbacks, the site administrator needs to make a directory (default $QBDIR/callback) and create a text-based configuration file, called "callbacks.conf" in that directory. Further, in the same directory, files containing the implementation (aka "code") of each Universal Callback must also be installed.

    The callbacks.conf file serves as a map that tells the system which callback code should be triggered to run on what events.

    The "callbacks.conf" file

    The callbacks.conf file is a text file, much like qb.conf, containing one or more lines with a "key = value" pair, associating each implementation file to a trigger event. The syntax is:

    ...

    Code Block
    #
    # callbacks.conf
    #
    # syntax of this file is :
    # filename = triggers
    #
    logFailuresToDB.py = failed-job-self-*
    mail-status.qcb = done-job-self
    checkWork.pl = done-work-self-*
    submitted.py = submit-job-self

    In this example, there are presumably 3 4 implementation files in the callback directory, logFailuresToDB.py, mail-status.qcb, submitted.py, and checkWork.pl, that have the implementation code in them.

    Note
    titleUse subprocess.Popen in callbacks

    If you ever need to run an external script in a callback, we recommend the use of subprocess.Popen() to run the external script inside the callback. This returns immediately and allows the callback to continue running, rather than blocking and waiting for the external script to complete; otherwise the supervisor process is tied up for the duration of the external script's execution.

    Do not use os.system() to run the external script, as this call will block until the external script exits. When a large number of callbacks tie up supervisor processes at the same time, your supervisor performance will suffer.

    Warning
    titleNever use sys.exit() in a callback

    Do not call sys.exit() at the end of the callback code, this kills the calling supervisor process.

    Code Block
    titlesubmitted.py
    languagepy
    #!/usr/bin/env python
    
    import sys
    import qb
    import traceback
    
    fh = open('/tmp/univeral_callback_test', 'a')
    try:
        # ==================================================
        #  === NOTE: ===
        #  the qb.jobinfo() in callbacks is not the
        #  same as the one in the external python API 
        # ==================================================
        job = qb.jobinfo("-id", qb.jobid())[0]
        fh.write('submitted %(id)s: %(name)s\n' % job)
    except:
        fh.write(traceback.format_exc())
    fh.close()
    

     

    Include+
    scrollPageId405BE23F014B092BED873659461D31E3
    scrollEditorDisplayTitle_universal_cb_vs_flightchecks
    scrollEditorUrlhttp://docs.pipelinefx.com/display/QUBE/._universal_cb_vs_flightchecks+v6.6-3

    qb.conf Parameters

    supervisor_universal_callback_path

    ...