Class: StarlingServer::Handler

Inherits:
EventMachine::Connection
  • Object
show all
Defined in:
lib/starling/handler.rb

Overview

This is an internal class that’s used by Starling::Server to handle the MemCache protocol and act as an interface between the Server and the QueueCollection.

Constant Summary collapse

DATA_PACK_FMT = 
"Ia*".freeze
ERR_UNKNOWN_COMMAND =

ERROR responses

"CLIENT_ERROR bad command line format\r\n".freeze
GET_COMMAND =

GET Responses

/\Aget (.{1,250})\s*\r\n/m
GET_RESPONSE = 
"VALUE %s %s %s\r\n%s\r\nEND\r\n".freeze
GET_RESPONSE_EMPTY = 
"END\r\n".freeze
SET_COMMAND =

SET Responses

/\Aset (.{1,250}) ([0-9]+) ([0-9]+) ([0-9]+)\r\n/m
SET_RESPONSE_SUCCESS = 
"STORED\r\n".freeze
SET_RESPONSE_FAILURE = 
"NOT STORED\r\n".freeze
SET_CLIENT_DATA_ERROR = 
"CLIENT_ERROR bad data chunk\r\nERROR\r\n".freeze
DELETE_COMMAND =

DELETE Responses

/\Adelete (.{1,250}) ([0-9]+)\r\n/m
DELETE_RESPONSE = 
"END\r\n".freeze
STATS_COMMAND =

STAT Response

/\Astats\r\n/m
STATS_RESPONSE = 
"STAT pid %d\r
STAT uptime %d\r
STAT time %d\r
STAT version %s\r
STAT rusage_user %0.6f\r
STAT rusage_system %0.6f\r
STAT curr_items %d\r
STAT total_items %d\r
STAT bytes %d\r
STAT curr_connections %d\r
STAT total_connections %d\r
STAT cmd_get %d\r
STAT cmd_set %d\r
STAT get_hits %d\r
STAT get_misses %d\r
STAT bytes_read %d\r
STAT bytes_written %d\r
STAT limit_maxbytes %d\r
%sEND\r\n".freeze
QUEUE_STATS_RESPONSE = 
"STAT queue_%s_items %d\r
STAT queue_%s_total_items %d\r
STAT queue_%s_logsize %d\r
STAT queue_%s_expired_items %d\r
STAT queue_%s_age %d\r\n".freeze
SHUTDOWN_COMMAND = 
/\Ashutdown\r\n/m
@@next_session_id = 
1

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Handler

Creates a new handler for the MemCache protocol that communicates with a given client.



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# File 'lib/starling/handler.rb', line 66

def initialize(options = {})
  @opts = options
end

Instance Method Details

#post_init ⇒ Object

Process incoming commands from the attached client.



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# File 'lib/starling/handler.rb', line 73

def post_init
  @stash = []
  @data = ""
  @data_buf = ""
  @server = @opts[:server]
  @logger = StarlingServer::Base.logger
  @expiry_stats = Hash.new(0)
  @expected_length = nil
  @server.stats[:total_connections] += 1
  set_comm_inactivity_timeout @opts[:timeout]
  @queue_collection = @opts[:queue]

  @session_id = @@next_session_id
  @@next_session_id += 1

  peer = Socket.unpack_sockaddr_in(get_peername)
  #@logger.debug "(#{@session_id}) New session from #{peer[1]}:#{peer[0]}"
end

#process(data) ⇒ Object 



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# File 'lib/starling/handler.rb', line 103

def process(data)
  data = @data_buf + data if @data_buf.size > 0
  # our only non-normal state is consuming an object's data
  # when @expected_length is present
  if @expected_length && data.size == @expected_length
    response = set_data(data)
    @data_buf = ""
    return response
  elsif @expected_length
    @data_buf = data
    return
  end
  case data
  when SET_COMMAND
    @server.stats[:set_requests] += 1
    set($1, $2, $3, $4.to_i)
  when GET_COMMAND
    @server.stats[:get_requests] += 1
    get($1)
  when STATS_COMMAND
    stats
  when SHUTDOWN_COMMAND
    # no point in responding, they'll never get it.
    Runner::shutdown
  when DELETE_COMMAND
    delete $1
  else
    logger.warn "Unknown command: #{data}."
    respond ERR_UNKNOWN_COMMAND
  end
rescue => e
  logger.error "Error handling request: #{e}."
  logger.debug e.backtrace.join("\n")
  respond GET_RESPONSE_EMPTY
end

#receive_data(incoming) ⇒ Object 



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# File 'lib/starling/handler.rb', line 92

def receive_data(incoming)
  @server.stats[:bytes_read] += incoming.size
  @data << incoming

  while data = @data.slice!(/.*?\r\n/m)
    response = process(data)
  end

  send_data response if response
end

#unbind ⇒ Object 



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# File 'lib/starling/handler.rb', line 139

def unbind
  #@logger.debug "(#{@session_id}) connection ends"
end