Class: EzPool::TimedStack

Inherits:
Object
  • Object
show all
Defined in:
lib/ezpool/timed_stack.rb

Overview

Examples:

ts = TimedStack.new(1) { MyConnection.new }

# fetch a connection
conn = ts.pop

# return a connection
ts.push conn

conn = ts.pop
ts.pop timeout: 5
#=> raises Timeout::Error after 5 seconds

Instance Method Summary collapse

Constructor Details

#initialize(connection_manager, size = 0) ⇒ TimedStack

Creates a new pool with size connections that are created by constructing the given connection_wrapper class



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# File 'lib/ezpool/timed_stack.rb', line 37

def initialize(connection_manager, size = 0)
  @created = 0
  @que = []
  @max = size
  @mutex = Mutex.new
  @resource = ConditionVariable.new
  @connection_manager = connection_manager
  @shutting_down = false
end

Instance Method Details

#abandon(connection_wrapper) ⇒ Object

Mark a connection as abandoned so that it cannot be used again. Will call the pre-configured shutdown proc, if provided.



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# File 'lib/ezpool/timed_stack.rb', line 97

def abandon(connection_wrapper)
  @mutex.synchronize do
    connection_wrapper.shutdown!
    @created -= 1
  end
end

#add_one ⇒ Object

Add one connection to the queue

Returns true iff a connection was successfully created



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# File 'lib/ezpool/timed_stack.rb', line 143

def add_one
  connection = try_create
  if connection.nil?
    false
  else
    push(connection)
    true
  end
end

#empty? ⇒ Boolean

Returns true if there are no available connections.

Returns:

  • (Boolean) 


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# File 'lib/ezpool/timed_stack.rb', line 121

def empty?
  (@created - @que.length) >= @max
end

#fill ⇒ Object

Pre-create all possible connections



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# File 'lib/ezpool/timed_stack.rb', line 134

def fill
  while add_one
  end
end

#length ⇒ Object

The number of connections available on the stack.



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# File 'lib/ezpool/timed_stack.rb', line 128

def length
  @max - @created + @que.length
end

#pop(timeout = 0.5, options = {}) ⇒ Object

Retrieves a connection from the stack. If a connection is available it is immediately returned. If no connection is available within the given timeout a Timeout::Error is raised.

:timeout is the only checked entry in options and is preferred over the timeout argument (which will be removed in a future release). Other options may be used by subclasses that extend TimedStack.



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# File 'lib/ezpool/timed_stack.rb', line 73

def pop(timeout = 0.5, options = {})
  options, timeout = timeout, 0.5 if Hash === timeout
  timeout = options.fetch :timeout, timeout

  deadline = EzPool.monotonic_time + timeout
  @mutex.synchronize do
    loop do
      raise EzPool::PoolShuttingDownError if @shutting_down
      return fetch_connection(options) if connection_stored?(options)

      connection = try_create(options)
      return connection if connection

      to_wait = deadline - EzPool.monotonic_time
      raise Timeout::Error, "Waited #{timeout} sec" if to_wait <= 0
      @resource.wait(@mutex, to_wait)
    end
  end
end

#push(wrapper, options = {}) ⇒ Object Also known as: <<

Returns obj to the stack. options is ignored in TimedStack but may be used by subclasses that extend TimedStack.



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# File 'lib/ezpool/timed_stack.rb', line 51

def push(wrapper, options = {})
  @mutex.synchronize do
    if @shutting_down
      wrapper.shutdown!
    else
      store_connection wrapper, options
    end

    @resource.broadcast
  end
end

#shutdown ⇒ Object

Shuts down the TimedStack which prevents connections from being checked out. Calls the shutdown program specified in the EzPool initializer



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# File 'lib/ezpool/timed_stack.rb', line 109

def shutdown()
  @mutex.synchronize do
    @shutting_down = true
    @resource.broadcast

    shutdown_connections
  end
end