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at-at
Simple ahead-of-time function scheduler. Allows you to schedule the execution of an anonymous function for a point in the future.
Basic Usage
First pull in the lib:
(use 'overtone.at-at)
at-at uses ScheduledThreadPoolExecutors behind the scenes which use a thread pool to run the scheduled tasks. You therefore need create a pool before you can get going:
(def my-pool (mk-pool))
It is possible to pass in extra options :cpu-count, :stop-delayed? and :stop-periodic? to further configure your pool. See mk-pool's docstring for further info.
Next, schedule the function of your dreams. Here we schedule the function to execute in 1000 ms from now (i.e. 1 second):
(at (+ 1000 (now)) #(println "hello from the past!") my-pool)
You may also specify a description for the scheduled task with the optional :desc key.
Another way of achieving the same result is to use after which takes a delaty time in ms from now:
(after 1000 #(println "hello from the past!") my-pool)
You can also schedule functions to occur periodically. Here we schedule the function to execute every second:
(every 1000 #(println "I am cool!") my-pool)
This returns a shceduled-fn which may easily be stopped stop:
(stop *1)
Or more forcefully killed with kill.
Finally, it's also possible to start a periodic repeating fn with an inital delay:
(every 1000 #(println "I am cool!") my-pool :initial-delay 2000)
Resetting a pool.
When necessary it's possible to stop and reset a given pool:
(stop-and-reset-pool! my-pool)
You may forcefully reset the pool using the :kill strategy:
(stop-and-reset-pool! my-pool :strategy :kill)
Viewing running scheduled tasks.
at-at keeps an eye on all the tasks you've scheduled. You can get a set of the current jobs (both scheduled and recurring) using scheduled-jobs and you can pretty-print a list of these job using show-schedule. The ids shown in the output of show-schedule are also accepted in kill and stop, provided you also specify the associated pool. See the kill and stop docstrings for more information.
(def tp (mk-pool))
(after 10000 #(println "hello") tp :desc "Hello printer")
(every 5000 #(println "I am still alive!") tp :desc "Alive task")
(show-schedule tp)
[6][RECUR] created: Thu 12:03:35s, period: 5000ms, desc: "Alive task
[5][SCHED] created: Thu 12:03:32s, starts at: Thu 12:03:42s, desc: "Hello printer
Install
Fetch at-at from github: https://github.com/overtone/at-at or pull from clojars: [overtone/at-at "X.Y.Z"]
History
at-at was extracted from the awesome music making wonder that is Overtone (http://github.com/overtone/overtone)
Authors
- Sam Aaron
- Jeff Rose
(Ascii art borrowed from http://www.sanitarium.net/jokes/getjoke.cgi?132)