Nested fibers can cause issues with Async, when spawning child tasks within them. I was affected by this issue when trying to create a streaming response from a Rails controller, using the proc do |stream| ... Async{....} end style response body. However, protocol-rackuses a normal fiber to wrap streaming responses and the child Async task has no parent, causing it to try and create a new event loop... meltdown ensues.
Ideally, Async and Sync helpers should work when any Fiber.scheduler is defined. Right now, it's unrealistic to expect Async::Task to work in any scheduler, but at the very least, the following should work:
reactor = Async::Reactor.new # internally calls Fiber.set_scheduler
# This should run in the above reactor:
Async do
puts "Hello World"
end
In order to do this, bare Async and Sync blocks should use Fiber.scheduler as a parent if possible.
Nested fibers can cause issues with Async, when spawning child tasks within them. I was affected by this issue when trying to create a streaming response from a Rails controller, using the
proc do |stream| ... Async{....} endstyle response body. However,protocol-rackuses a normal fiber to wrap streaming responses and the child Async task has no parent, causing it to try and create a new event loop... meltdown ensues.Ideally,
AsyncandSynchelpers should work when anyFiber.scheduleris defined. Right now, it's unrealistic to expectAsync::Taskto work in any scheduler, but at the very least, the following should work:In order to do this, bare
AsyncandSyncblocks should useFiber.scheduleras a parent if possible.Types of Changes
Contribution