ScriptClient.py

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#!/usr/local/bin/python
#
#                               Copyright 2004
#                                     by
#                        The Board of Trustees of the
#                     Leland Stanford Junior University.
#                            All rights reserved.
#

__facility__ = "Online"
__abstract__ = "Current Value Table Client"
__author__  = "Jim Panetta <panetta@slac.stanford.edu> SLAC - GLAST LAT I&T/Online"
__date__     = ("$Date: 2006/01/28 05:35:26 $").split(' ')[1]
__version__ = "$Revision: 1.9 $"
__release__  = "$Name: HEAD $"
__credits__ = "SLAC"

import LICOS.copyright_SLAC

import LICOS.util.gOptions as gOptions


import socket, threading, time, struct
from binascii import hexlify
import cPickle as pickle

from LICOS.lib.currValTable.CurrValTable import *

class ScriptClient( socket.socket ):
  MAXLENGTH = 0x10000
  def __init__( self, serverHost, port ):
    socket.socket.__init__( self, socket.AF_INET, socket.SOCK_STREAM )
    
    self.connect( ( serverHost, port ) )
    self.__read()
    
    self.delimiter  = "\r\n"
    
  def __read( self ):
    # Receive a packet in the fomat "LL......" where LL is a ushort
    # designating the size of the string.
    resp = self.recv(2)
    lbuf = ord(resp[0])*256 + ord(resp[1])
    
    buf = self.recv(lbuf)
    resp = buf[0:3]
    pkt  = buf[3:]
    
    # print lbuf, len(buf)
    if resp == 'ok ':
      self.connectionState = True
      return
    if resp == 'rq ':
      # a pickled object is sent across the network in the byte format:
      # 'rq ...'
      # print hexlify(pkt)
      # REVISIT:   do something about handling the "no value" problem
      cv = decodeCurrentValue(pkt)
      self.__reply = cv

  def __sendLine( self, data ):
    # Send a packet in the fomat "LL......" where LL is a ushort
    # designating the size of the string.
    ld = len(data)
    if ld >= 0x10000:
      raise IOError, "data buffer too long! len(data) = %d" % ld
    ldd = divmod(ld,256)
    line = chr(ldd[0]) + chr(ldd[1]) + data 
    self.send(line)

      
  def request(self, mnem):
    query = 'request'
    query += ' ' + mnem
    self.__sendLine(query)
    self.__read()
    
    result = self.__reply
    return result

  def poll(self, mnem, timeout=None, maxAge=None):
    """!\brief poll member function
    
    Poll for a mnemonic where the age < maxAge (seconds) with a
    specified timeout.  If timeout is None (or 0) respond immediately.
    
    \param mnem     Mnemonic to request
    \param timeout  Maximum time to wait for a response
    \param maxAge   Maximum age of object  (timeout required parameter)
    """
    now = time.time()
    wait = 0.2 # seconds
    while True:  # always do the loop once
      rq = self.request(mnem)
      if timeout is None:                # no timeout
        break
      if rq is not None:                 # non empty response
        if maxAge is not None:
          if ( now - rq.age() ) < maxAge: # new enough!
            break
        else:                            # no age requirement
          break
      if timeout <= 0:                   # expired unsatisfied, return None
        rq = None
        break
      time.sleep(min(wait, timeout))
      timeout -= wait
      wait *= 1.5                        # exponential back off
    
    return rq


def runScript(cvc):
  
  while cvc.connectionState is False:
    print "waiting for Godot..."
    time.sleep(1)
  
  flags = ['age', '']
  ml = ["LLFSDDMPFHDR31"]#, "LLFSRDMPARCFLG", "LLFSRDMPFFILE", "LLFSRDMPFSTIME", "LLFSSYSSLATUNIT", "LLFSSYSSXACTID", "LLFSSYSSFDEV"]

  for mnem in ml:
    rq = cvc.request(mnem)
    print mnem, rq.rawValue(), rq.name
    time.sleep(0.5)
    


if __name__ == '__main__':
    
  options = gOptions.Options(['cvtHost', 'cvtPort'])
  try:
    options.parse()
  except Exception, msg:
    options.usage(str(msg))
    exit  
    
  cvtHost     = options.cvtHost
  cvtPort = int(options.cvtPort)
  
  
  cvc = ScriptClient( cvtHost, cvtPort )

  scriptThread = threading.Thread(name="scriptThread", target=runScript, args=(cvc,))
  scriptThread.start()

  scriptThread.join()

  cvc.close()



#eof

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