Class: Async::HTTP::Pool

Inherits:
Object
  • Object
show all
Defined in:
lib/async/http/pool.rb

Overview

Pool behaviours

  • Single request per connection (HTTP/1 without keep-alive)

  • Multiple sequential requests per connection (HTTP1 with keep-alive)

  • Multiplex requests per connection (HTTP2)

In general we don’t know the policy until connection is established.

This pool doesn’t impose a maximum number of open resources, but it WILL block if there are no available resources and trying to allocate another one fails.

Resources must respond to #multiplex -> 1 or more. #reusable? -> can be used again.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(limit = nil, &block) ⇒ Pool

Returns a new instance of Pool.



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# File 'lib/async/http/pool.rb', line 43

def initialize(limit = nil, &block)
  @resources = {} # resource => count
  @available = Async::Notification.new
  
  @limit = limit
  
  @constructor = block
  @guard = Async::Semaphore.new(1)
end

Instance Attribute Details

#resources ⇒ Object (readonly)

All allocated resources.



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# File 'lib/async/http/pool.rb', line 73

def resources
  @resources
end

Instance Method Details

#acquire ⇒ Object 



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# File 'lib/async/http/pool.rb', line 79

def acquire
  resource = wait_for_resource
  
  return resource unless block_given?
  
  begin
    yield resource
  ensure
    release(resource)
  end
end

#active ⇒ Object

The number of allocated resources.



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# File 'lib/async/http/pool.rb', line 54

def active
  @resources.count
end

#busy? ⇒ Boolean

Whether there are resources which are currently in use.

Returns:

  • (Boolean) 


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# File 'lib/async/http/pool.rb', line 59

def busy?
  @resources.collect do |_, usage|
    return true if usage > 0
  end
  
  return false
end

#close ⇒ Object 



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# File 'lib/async/http/pool.rb', line 101

def close
  @resources.each_key(&:close)
  @resources.clear
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/async/http/pool.rb', line 75

def empty?
  @resources.empty?
end

#release(resource) ⇒ Object

Make the resource resources and let waiting tasks know that there is something resources.



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# File 'lib/async/http/pool.rb', line 92

def release(resource)
  # A resource that is not good should also not be reusable.
  if resource.reusable?
    reuse(resource)
  else
    retire(resource)
  end
end

#to_s ⇒ Object 



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# File 'lib/async/http/pool.rb', line 106

def to_s
  "\#<#{self.class} resources=#{availability_string} limit=#{@limit.inspect}>"
end

#wait ⇒ Object

Wait until a pool resource has been freed.



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# File 'lib/async/http/pool.rb', line 68

def wait
  @available.wait
end