The extra in the event specification refers to the type of event. Each type of event may require additional information.
In the case of the job, it requires nothing more. However in the case of the subjob it requires the subjob's ID number.
Example:
When the job's instance #5 is done, execute callback: done-subjob-self-5
Extra information required by each type:
job | None |
subjob | subjobid |
work | workid/name |
host | hostname |
time | timeofday |
repeat | timeofday-interval |
global | None |
globaltime | timeofday |
globalrepeat | timeofday-interval |