irb and async? about async HOT 15 CLOSED

There was an unfortunate bug and this will be fixed in Ruby 3.1.1.

from async.

I guess I can start my Server (and the Async reactor) in a thread. But then I can't use things like waiting for states of the server, which internally use Async::Notification?

from async.

Do you mean running IRB inside an Async block, and using Async IO objects as input/output to IRB?

from async.

It should be possible to feed non-blocking IO into IRB, but I haven’t tried it.

@aycabta any thoughts? What interface is required to do it?

from async.

Yes it should be possible to do that. You can check if the IRB call is within an Async task and then use async io stdin/stdout.

from async.

Gave it a try, and it seems to work fairly well:
https://gist.github.com/emiltin/d382d1527d771afa8130b174e323539f

# counter.rb
require 'async'
class Counter
	attr_reader :count
	def initialize
		@count = 0
		Async do |task|
			loop do
				task.sleep 1
				@count = @count + 1
			end
		end
	end
end

Emils-MacBook-Air-2:async-irb emiltin$ ./irb
irb(main):001:0> require './counter'
=> true
irb(main):002:0> c=Counter.new
=> #<Counter:0x00007fcac906c750 @count=0>
irb(main):003:0> c.count
=> 2
irb(main):004:0> c.count     # let's wait a bit and look again
=> 17                        # yay, it's counting in the background!
irb(main):005:0> sleep 20    # will this work?
=> 20         
irb(main):006:0> c.count     # 20 seconds later
=> 24                        # not right, we need use async task.sleep

from async.

Looking at https://github.com/ruby/irb/blob/master/lib/irb/input-method.rb, encoding() and eof() probably also needs to be implemented.
Another thing that doesn't work is arrow-up to select previous lines, any idea why that is?

from async.

Sleeping can be done with Async::Task.current.sleep 10. Would it make sense to have a class method for putting the curent task to sleep, like Async.sleep?

from async.

When you have async tasks that output stuff in the background, it can be hard to see what you're typing. I was hoping irb sesions could be used to keep noisy tasks in the background, while you interact with them in a separate session.

But sessions are based on threads and background sessions seems to be put to sleep:

irb#1(main):009:0> jobs
=> #0->irb on main (#<Thread:0x00007fa697064088 sleep_forever>: stop)
#1->irb#1 on main (#<Thread:0x00007fa697888278@/Users/emiltin/.rbenv/versions/2.6.3/lib/ruby/2.6.0/irb/ext/multi-irb.rb:192 run>: running)

from async.

The way I wanted to solve this was by having a separate process connect to the running process from a different terminal.

from async.

@aycabta wondering if you've had time to explore this?

from async.

This is now fixed in Async 2.0.

from async.

Goods news!
How is it used? If I just use an Async block, it only returns once it's complete, as expected.

irb(main):008:0> t=Async {|task| task.sleep 2}      # blocks for 2 seconds
=> #<Async::Task:0x38720>
irb(main):009:0> t.status
=> :complete

How can I run async tasks, while interacting with irb at the same time?

from async.

Maybe this video helps answer that?

https://www.youtube.com/watch?v=9StgQAwR3kw

from async.

hi @bruno thank you, I just found it too! it basically show want i would like to do, but it seems to be a demo running a customized version of irb? at least i can't reproduce the behaviour with the standard irb in ruby 3.1.0. Async { binding.irb } blocks.

from async.