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SideTask is an alternative to Elixir'sTask.Supervisor that uses Basho'ssidejob library for better parallelism and to support capacitylimiting ofTasks.

Elixir'sTask.Supervisor is implemented as a single:simple_one_for_one supervisor with theindividualTasks as children. This means starting a new task has to go through this singlesupervisor. Furthermore there is no limit to the number of workers that can be running at the sametime.

Basho's sidejob library spawns multiple supervisors (one for each scheduler by default) anduses ETS tables to keep track of the number of workers, thereby making it possible to startworkers in parallel while also putting an upper bound on the number of running workers.

SideTask provides an API similar toTask.Supervisor, with the addition that all calls thatstart a new task require a sidejob resource as argument and can return{:error, :overload}.

Convenience functions for adding and deleting sidejob resources are provided.

SideTask.add_resource(:example1,50)potential_tasks=fori<-1..100docaseSideTask.async(:example1,fn->:timer.sleep(1000);iend)do{:ok,task}->IO.puts"Task#{i} created"task{:error,:overload}->IO.puts"Task#{i} not created, overloaded"nilendendIO.inspectfortask=%Task{}<-potential_tasks,do:Task.await(task)

# Erlang spawns one scheduler per CPU core by defaultschedulers=:erlang.system_info(:schedulers)SideTask.add_resource(:example2,schedulers*2)forscheduler<-1..schedulersdospawn_linkfn ->fori<-Stream.iterate(0,&(&1+1))doSideTask.start_child:example2,fn->:timer.sleep(250);IO.inspectscheduler:scheduler,count:iendendendend

This software is licensed underthe MIT license.

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