How to start/end reactor?

[YusukeIwaki]

Hi, thank you for providing very awesome async library for Ruby.
I have an issue on using Async in my browser-automation library.

I understand this async library requires root reactor session with Async { ... } or Async::Reactor.run{ ... }.
Sometimes it is hard to define an async session using block, for example:

browser.on(:start) do
  # start async reactor session here
end

browser.on(:exit) do
  # end reactor session here
end

Can we define Async reactor session without block?

[ioquatix]

Hi, thank you for providing very awesome async library for Ruby.

Thanks so much for your feedback.

Can we define Async reactor session without block?

Yes it is possible but you take on the responsibility of controlling it correctly and this isn't what I'd consider a typical use case.

Also you need to manually run the reactor for a short time in your own loop, e.g.

require_relative "async"

# browser.on(:start) do
reactor = Async::Reactor.new

# Schedule task:
reactor.async do |task|
	while true
		task.sleep(1)
		puts "Hello from task"
	end
end

10.times do
	# Host the reactor in your own run loop:
	reactor.run do |task|
		# Run for a fixed duration:
		#task.sleep 1
		
		# Run for one iteration:
		task.yield
		
		# Stop the reactor loop:
		reactor.interrupt
	end
	
	# Other stuff
	sleep 0.5
end

#browser.on(:exit) do
reactor.stop

I don't know how your run loop works, but essentially you must iterate the event loop every now and then.

Calling Async{} will not work as expected unless it's inside the context of the reactor.async block.

I would suggest you take a look at https://github.com/socketry/async-rspec/blob/master/lib/async/rspec/reactor.rb too - this shows how to use a per-spec reactor which might make more sense for your use case.