These are the environment variables that need to be set before an notification script is launched:

PEGASUS_EVENT ---> The value of the when attribute (note that for 'all' we will change it to one of the following: 'start' or 'at_end')
PEGASUS_STATUS ---> The exit status of the graph node. Only available for end notifications. Not available if there is no exitcode.
PEGASUS_SUBMIT_DIR ---> Always present, in which directory to find the job (or workflow).
PEGASUS_JOBID ---> The job identifier (name) for job and invocation notifications. For workflow notification, this is the workflow identifier.
PEGASUS_STDOUT ---> For job and invocation notifications, the full filename where stdout goes. For workflow notifications, the path to the dagman.out file. Empty and possibly non-existent at submit time (though we still have the filename). The kickstart record for job nodes.
PEGASUS_STDERR ---> The full filename where stderr goes. For workflow notifications, this is not present. Empty and possibly non-existent at submit time (though we still have the filename).
PEGASUS_EVENT_TIMESTAMP ---> The time when the event happened in EPOCH format.
PEGASUS_EVENT_TIMESTAMP_ISO ---> Same as above, but in ISO format (human readable).
PEGASUS_INVID --> The invocation identifier. This is only present in invocation notifications.
PEGASUS_WFID --> The dax name + the dax index (from the braindump.txt file), in the form of DAX_NAME+""+DAX_INDEX (e.g. montage-0)

Notifications will be implemented in a "best effort" mode, and will be tried only one time.