Class: ZooKeeper::RubyIO::Connection

Inherits:
Object
  • Object
show all
Includes:
Slf4r::Logger, Socket::Constants, Protocol
Defined in:
lib/zkruby/rubyio.rb

Constant Summary

Constants included from Protocol

Protocol::MIN_PACKET

Instance Method Summary collapse

Methods included from Protocol

#receive_data, #send_records

Constructor Details

#initialize(host, port, timeout, session) ⇒ Connection

Returns a new instance of Connection.



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# File 'lib/zkruby/rubyio.rb', line 33

def initialize(host,port,timeout,session)
    @session = session
    @write_queue = Queue.new()

    # JRuby cannot do non-blocking connects, which means there is
    # no way to properly implement the connection-timeout
    # See http://jira.codehaus.org/browse/JRUBY-5165 
    # In any case this should be encapsulated in TCPSocket.open(host,port,timeout)
    if RUBY_PLATFORM == "java"
        begin
            sock = TCPSocket.new(host,port.to_i)
        rescue Errno::ECONNREFUSED
            logger.warn("TCP Connection refused to #{host}:#{port}")
            sock = nil
        end
    else
        addr = Socket.getaddrinfo(host, nil)
        sock = Socket.new(Socket.const_get(addr[0][0]), Socket::SOCK_STREAM, 0)
        sock.setsockopt(SOL_SOCKET, SO_LINGER, [0,-1].pack("ii"))
        sock.setsockopt(SOL_TCP, TCP_NODELAY,[0].pack("i_"))
        sockaddr = Socket.pack_sockaddr_in(port, addr[0][3])
        begin
            sock.connect_nonblock(sockaddr)
        rescue Errno::EINPROGRESS
            resp = IO.select(nil, [sock], nil, timeout)
            begin
                sock.connect_nonblock(sockaddr)
            rescue Errno::ECONNREFUSED
                logger.warn("Connection refused to #{ host }:#{ port }")
                sock = nil
            rescue Errno::EISCONN
            end
        end
    end
    @socket = sock
    Thread.new(sock) { |sock| write_loop(sock) } if sock
end

Instance Method Details

#disconnect ⇒ Object 



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# File 'lib/zkruby/rubyio.rb', line 129

def disconnect()
    socket = @socket
    @socket = nil
    socket.close if socket
rescue Exception => ex
    #oh well
    logger.debug("Exception closing socket",ex)
end

#read_loop ⇒ Object 



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# File 'lib/zkruby/rubyio.rb', line 97

def read_loop()
    socket = @socket
    ping = 0
    while socket # effectively forever
        begin
            data = socket.read_nonblock(1024)
            logger.debug { "Received (#{data.length})" + data.unpack("H*")[0] }
            receive_data(data)
            ping = 0
        rescue IO::WaitReadable
            select_result = IO.select([socket],[],[],@session.ping_interval)
            unless select_result
                ping += 1
                # two timeouts in a row mean we need to send a ping
                case ping
                when 1 ; @session.synchronize { @session.ping() }
                when 2
                    logger.debug{"No response to ping in #{@session.ping_interval}*2"}
                    break
                end
            end
        rescue EOFError
            logger.debug { "EOF reading from socket" }
            break
        rescue Exception => ex
            logger.warn( "#{ex.class} exception in readloop",ex )
            break
        end
    end
    disconnect()
end

#receive_records(packet_io) ⇒ Object

Protocol requirement



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# File 'lib/zkruby/rubyio.rb', line 139

def receive_records(packet_io)
    @session.synchronize { @session.receive_records(packet_io) }
end

#send_data(data) ⇒ Object

This is called from random client threads, but only within a @session.synchronized() block



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# File 'lib/zkruby/rubyio.rb', line 73

def send_data(data)
    @write_queue.push(data)
end

#write_loop(socket) ⇒ Object

Since this runs in its very own thread we can use boring blocking IO



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# File 'lib/zkruby/rubyio.rb', line 79

def write_loop(socket)
    Thread.current[:name] = "ZooKeeper::RubyIO::WriteLoop"
    begin
        while socket
            data = @write_queue.pop()
            if socket.write(data) != data.length()
                #TODO - will this really ever happen
                logger.warn("Incomplete write!")
            end
            logger.debug { "Sending: " + data.unpack("H*")[0] }
        end
    rescue Exception => ex
        logger.warn("Exception in write loop",ex)
        disconnect()
    end

end