BackgroundTaskPool.md

ipc.BackgroundTaskPool

BackgroundTaskPool combines ipc.map and ipc.workqueue to implement a very simple, pollable, way to run a set of arbitrary Lua functions as background tasks. You construct a BackgroundTaskPool with the size of the thread pool you would like to run your tasks on.

   local BackgroundTaskPool = require 'ipc.BackgroundTaskPool'
   local pool = BackgroundTaskPool(13) -- create a pool with 13 worker threads

Call addTask with a function and a set of arguments to add a task into the pool.

   for i = 1,42 do
      pool.addTask(function(i)
         return math.sqrt(i)
      end, i)
   end

You can optionally poll for the completion of all tasks or just one task.

   -- is the task with id 7 done?
   if pool.isDone(7) then
      print('the 7th is done!')
   end
   -- are all the tasks done?
   if pool.isDone() then
      print('all tasks are done!')
   end

When you want the result for a task, call getResult with the task id. If the task function threw an error then the getResult call will throw that same error.

   for i = 1,42 do
      assert(pool.getResult(i) == math.sqrt(i))
   end

Note that ipc.BackgroundTaskPool will throw an error when attempting to serialize closures/upvalues. However ipc.workqueue provides :writeup() for serializing closures/upvalues.