Class: Async::Postgres::Pool

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

Overview

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.

Instance Method Summary collapse

Constructor Details

#initialize(&block) ⇒ Pool 



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# File 'lib/async/postgres/pool.rb', line 65

def initialize(&block)
  @available = []
  @waiting = []
  
  @constructor = block
end

Instance Method Details

#acquire ⇒ Object 



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# File 'lib/async/postgres/pool.rb', line 72

def acquire
  resource = wait_for_next_available
  
  begin
    yield resource
  ensure
    @available << resource
    
    if task = @waiting.pop
      task.resume
    end
  end
end

#close ⇒ Object 



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# File 'lib/async/postgres/pool.rb', line 86

def close
  @available.each(&:close)
  @available.clear
end

#next_available ⇒ Object 



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# File 'lib/async/postgres/pool.rb', line 100

def next_available
  if @available.empty?
    return @constructor.call # This might fail, which is okay :)
  else
    return @available.pop
  end
rescue StandardError
  $stderr.puts $!.inspect
  return nil
end

#wait_for_next_available ⇒ Object 



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# File 'lib/async/postgres/pool.rb', line 91

def wait_for_next_available
  until resource = next_available
    @waiting << Fiber.current
    Task.yield
  end
  
  return resource
end