Class: Server

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

Overview

This class represents a redis server instance.

Constant Summary collapse

RETRY_DELAY =

The amount of time to wait before attempting to re-establish a connection with a server that is marked dead.

30.0

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(host, port = DEFAULT_PORT, timeout = 10) ⇒ Server

Create a new Redis::Server object for the redis instance listening on the given host and port.

Raises:

  • (ArgumentError) 


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# File 'lib/server.rb', line 62

def initialize(host, port = DEFAULT_PORT, timeout = 10)
  raise ArgumentError, "No host specified" if host.nil? or host.empty?
  raise ArgumentError, "No port specified" if port.nil? or port.to_i.zero?

  @host   = host
  @port   = port.to_i

  @sock   = nil
  @retry  = nil
  @status = 'NOT CONNECTED'
  @timeout = timeout
end

Instance Attribute Details

#host ⇒ Object (readonly)

The host the redis server is running on.



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# File 'lib/server.rb', line 36

def host
  @host
end

#port ⇒ Object (readonly)

The port the redis server is listening on.



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# File 'lib/server.rb', line 41

def port
  @port
end

#replica ⇒ Object (readonly)

Returns the value of attribute replica.



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# File 'lib/server.rb', line 46

def replica
  @replica
end

#retry ⇒ Object (readonly)

The time of next retry if the connection is dead.



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# File 'lib/server.rb', line 51

def retry
  @retry
end

#status ⇒ Object (readonly)

A text status string describing the state of the server.



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# File 'lib/server.rb', line 56

def status
  @status
end

Instance Method Details

#close ⇒ Object

Close the connection to the redis server targeted by this object. The server is not considered dead.



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# File 'lib/server.rb', line 141

def close
  @sock.close if @sock && !@sock.closed?
  @sock   = nil
  @retry  = nil
  @status = "NOT CONNECTED"
end

#connect_to(host, port, timeout = nil) ⇒ Object 



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# File 'lib/server.rb', line 110

def connect_to(host, port, timeout=nil)
  socket = TCPSocket.new(host, port, 0)
  if timeout
    socket.instance_eval <<-EOR
      alias :blocking_gets :gets
      def gets(*args)
        RedisTimer.timeout(#{timeout}) do
          self.blocking_gets(*args)
        end
      end
      alias :blocking_read :read
      def read(*args)
        RedisTimer.timeout(#{timeout}) do
          self.blocking_read(*args)
        end
      end
      alias :blocking_write :write
      def write(*args)
        RedisTimer.timeout(#{timeout}) do
          self.blocking_write(*args)
        end
      end
    EOR
  end
  socket
end

#inspect ⇒ Object

Return a string representation of the server object.



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# File 'lib/server.rb', line 77

def inspect
  "<Redis::Server: %s:%d (%s)>" % [@host, @port, @status]
end

#mark_dead(error) ⇒ Object

Mark the server as dead and close its socket.



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# File 'lib/server.rb', line 150

def mark_dead(error)
  @sock.close if @sock && !@sock.closed?
  @sock   = nil
  @retry  = Time.now #+ RETRY_DELAY

  reason = "#{error.class.name}: #{error.message}"
  @status = sprintf "%s:%s DEAD (%s), will retry at %s", @host, @port, reason, @retry
  puts @status
end

#socket ⇒ Object

Try to connect to the redis server targeted by this object. Returns the connected socket object on success or nil on failure.



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# File 'lib/server.rb', line 85

def socket
  return @sock if @sock and not @sock.closed?

  @sock = nil

  # If the host was dead, don't retry for a while.
  return if @retry and @retry > Time.now

  # Attempt to connect if not already connected.
  begin
    @sock = connect_to(@host, @port, @timeout)
    @sock.setsockopt Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1
    @retry  = nil
    @status = 'CONNECTED'
  rescue Errno::EPIPE, Errno::ECONNREFUSED => e
    puts "Socket died... socket: #{@sock.inspect}\n" if $debug
    @sock.close
    retry
  rescue SocketError, SystemCallError, IOError => err
    puts "Unable to open socket: #{err.class.name}, #{err.message}" if $debug
    mark_dead err
  end
  @sock
end