A Trapperkeeper service that provides a simple API for scheduling background tasks.
Other Trapperkeeper services may specify a dependency on the Scheduler service, and then use its functions to schedule and cancel jobs to be run on background worker threads.
The SchedulerService
provides some simple API for scheduling (potentially
recurring) background tasks. The service manages the lifecycle of the underlying
scheduling subsystem so that other services don't need to (and avoids potential issues
around multiple services attempting to initialize the same scheduling subystem
in a single JVM process).
The functions that are currently available are as follows:
interspaced [interval-ms f]
: schedules a job that will callf
, block until that call completes, sleep forinterval-ms
milliseconds, and then repeat. Returns an identifier that can be used to reference this scheduled job (e.g., for cancellation) later.interspaced [interval-ms f group-id]
: schedules a job that will callf
, block until that call completes, sleep forinterval-ms
milliseconds, and then repeat. Returns an identifier that can be used to reference this scheduled job (e.g., for cancellation) later. A group identifiergroup-id
can be provided that allows jobs in the same group to be stopped at the same time.after [interval-ms f]
: schedules a job that will callf
a single time, after a delay ofinterval-ms
milliseconds. Returns an identifier that can be used to reference this scheduled job (e.g. for cancellation) later.after [interval-ms f group-id]
: schedules a job that will callf
a single time, after a delay ofinterval-ms
milliseconds. Returns an identifier that can be used to reference this scheduled job (e.g. for cancellation) later. A group identifiergroup-id
can be provided that allows jobs in the same group to be stopped at the same time.stop-job [job-id]
: Given ajob-id
returned by one of the previous functions, cancels the job. If the job is currently executing it will be allowed to complete, but will not be invoked again afterward. Returnstrue
if the job was successfully stopped,false
otherwise.stop-grouped-jobs [group-id]
: Given agroup-id
identifier, cancel all the jobs associated with thatgroup-id
. If any of the jobs are currently executing they will be allowed to complete, but will not be invoked again afterward. Returns a sequence of maps, one for each job in the group, with each map containing thejob
and a booleanstopped?
key indiciating if the job was stopped successfully or not.count-jobs []
: Return a count of the total number of scheduled jobs known to to the scheduling service.after
jobs that have completed won't be included in the total.count-jobs [group-id]
: Return a count of the total number of scheduled jobs with the associatedgroup-id
known to to the scheduling service.after
jobs that have completed won't be included in the total.get-jobs []
: return a list of the current job identifiersget-jobs [group-id]
: return a list of the current job identifiers associated with the specified group identifier
The current implementation of the SchedulerService
is a wrapper around
the org.quartz-scheduler/quartz
library.
- Add additional scheduling API functions, e.g.
every
. - Add API for introspecting the state of currently scheduled jobs
#Support
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