# class Bundler::ConnectionPool

Generic connection pool class for e.g. sharing a limited number of network connections among many threads. Note: Connections are lazily created.

Example usage with block (faster):

    @pool = Bundler::ConnectionPool.new { Redis.new }

    @pool.with do |redis|
      redis.lpop('my-list') if redis.llen('my-list') > 0
    end

Using optional timeout override (for that single invocation)

    @pool.with(timeout: 2.0) do |redis|
      redis.lpop('my-list') if redis.llen('my-list') > 0
    end

Example usage replacing an existing connection (slower):

    $redis = Bundler::ConnectionPool.wrap { Redis.new }

    def do_work
      $redis.lpop('my-list') if $redis.llen('my-list') > 0
    end

Accepts the following options:

- :size - number of connections to pool, defaults to 5

- :timeout - amount of time to wait for a connection if none currently available, defaults to 5 seconds

### Constants

DEFAULTS
GLOBAL_MONOTONIC_CLOCK

  Clock that cannot be set and represents monotonic time since some unspecified starting point.

  @!visibility private

VERSION

### Public Class Methods

monotonic_time() click to toggle source

Returns the current time a tracked by the application monotonic clock.

@return [Float] The current monotonic time when `since` not given else

    the elapsed monotonic time between `since` and the current time

    # File lib/bundler/vendor/connection_pool/lib/connection_pool/monotonic_time.rb, line 62
    def monotonic_time
      GLOBAL_MONOTONIC_CLOCK.get_time
    end

new(options = {}, &block) click to toggle source

    # File lib/bundler/vendor/connection_pool/lib/connection_pool.rb, line 44
    def initialize(options = {}, &block)
      raise ArgumentError, 'Connection pool requires a block' unless block

      options = DEFAULTS.merge(options)

      @size = options.fetch(:size)
      @timeout = options.fetch(:timeout)

      @available = TimedStack.new(@size, &block)
      @key = :"current-#{@available.object_id}"
      @key_count = :"current-#{@available.object_id}-count"
    end

wrap(options, &block) click to toggle source

    # File lib/bundler/vendor/connection_pool/lib/connection_pool.rb, line 40
    def self.wrap(options, &block)
      Wrapper.new(options, &block)
    end

### Public Instance Methods

available() click to toggle source

Number of pool entries available for checkout at this instant.

    # File lib/bundler/vendor/connection_pool/lib/connection_pool.rb, line 122
    def available
      @available.length
    end

checkin() click to toggle source

    # File lib/bundler/vendor/connection_pool/lib/connection_pool.rb, line 97
    def checkin
      if ::Thread.current[@key]
        if ::Thread.current[@key_count] == 1
          @available.push(::Thread.current[@key])
          ::Thread.current[@key]= nil
        else
          ::Thread.current[@key_count]-= 1
        end
      else
        raise Bundler::ConnectionPool::Error, 'no connections are checked out'
      end

      nil
    end

checkout(options = {}) click to toggle source

    # File lib/bundler/vendor/connection_pool/lib/connection_pool.rb, line 87
    def checkout(options = {})
      if ::Thread.current[@key]
        ::Thread.current[@key_count]+= 1
        ::Thread.current[@key]
      else
        ::Thread.current[@key_count]= 1
        ::Thread.current[@key]= @available.pop(options[:timeout] || @timeout)
      end
    end

get_time() click to toggle source

@!visibility private

    # File lib/bundler/vendor/connection_pool/lib/connection_pool/monotonic_time.rb, line 15
    def get_time
      Process.clock_gettime(Process::CLOCK_MONOTONIC)
    end

shutdown(&block) click to toggle source

    # File lib/bundler/vendor/connection_pool/lib/connection_pool.rb, line 112
    def shutdown(&block)
      @available.shutdown(&block)
    end

size() click to toggle source

Size of this connection pool

    # File lib/bundler/vendor/connection_pool/lib/connection_pool.rb, line 117
    def size
      @size
    end

with(options = {}) { |conn| ... } click to toggle source

MRI

    # File lib/bundler/vendor/connection_pool/lib/connection_pool.rb, line 60
    def with(options = {})
      Thread.handle_interrupt(Exception => :never) do
        conn = checkout(options)
        begin
          Thread.handle_interrupt(Exception => :immediate) do
            yield conn
          end
        ensure
          checkin
        end
      end
    end