Class: EventMachine::Synchrony::ConnectionPool

Inherits:
Object
  • Object
show all
Defined in:
lib/em-synchrony/connection_pool.rb

Instance Method Summary collapse

Constructor Details

#initialize(opts, &block) ⇒ ConnectionPool

Returns a new instance of ConnectionPool.



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# File 'lib/em-synchrony/connection_pool.rb', line 7

def initialize(opts, &block)
  @reserved  = {}   # map of in-progress connections
  @available = []   # pool of free connections
  @pending   = []   # pending reservations (FIFO)

  opts[:size].times do
    @available.push(block.call) if block_given?
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &blk) ⇒ Object (private)

Allow the pool to behave as the underlying connection

If the requesting method begins with “a” prefix, then hijack the callbacks and errbacks to fire a connection pool release whenever the request is complete. Otherwise yield the connection within execute method and release once it is complete (assumption: fiber will yield until data is available, or request is complete)



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# File 'lib/em-synchrony/connection_pool.rb', line 66

def method_missing(method, *args, &blk)
  async = (method[0,1] == "a")

  execute(async) do |conn|
    df = conn.__send__(method, *args, &blk)

    if async
      fiber = Fiber.current
      df.callback { release(fiber) }
      df.errback { release(fiber) }
    end

    df
  end
end

Instance Method Details

#execute(async) ⇒ Object

Choose first available connection and pass it to the supplied block. This will block indefinitely until there is an available connection to service the request.



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# File 'lib/em-synchrony/connection_pool.rb', line 20

def execute(async)
  f = Fiber.current

  begin
    conn = acquire(f)
    yield conn
  ensure
    release(f) if not async
  end
end