Source Code for Module AIPSTV

  1  # Copyright (C) 2005 Joint Institute for VLBI in Europe 
  2  # 
  3  # This program is free software; you can redistribute it and/or modify 
  4  # it under the terms of the GNU General Public License as published by 
  5  # the Free Software Foundation; either version 2 of the License, or 
  6  # (at your option) any later version. 
  7  # 
  8  # This program is distributed in the hope that it will be useful, 
  9  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 10  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 11  # GNU General Public License for more details. 
 12   
 13  # You should have received a copy of the GNU General Public License 
 14  # along with this program; if not, write to the Free Software 
 15  # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 16   
 17  """ 
 18   
 19  This module provides the AIPSTV class.  This class makes it possible 
 20  to control the AIPS TV from Python. 
 21   
 22  """ 
 23   
 24  # Generic Python stuff. 
 25  import os, socket, struct, time 
 26   
 27   
 28 -class AIPSTV(object): 
 29 -    def __init__(self, host='localhost'): 
 30          self.host = host 
 31          self.port = socket.getservbyname('sssin', 'tcp') 
 32          self._lock_pid = 0 
 33          self._server_pid = 0 
 34          return 
 35   
 36 -    def _send(self, opcode, dat1=0, dat2=0, dat3=0, dat4=0): 
 37          """Send command to the AIPS TV server.""" 
 38   
 39          s = struct.pack('!6h', opcode, dat1, dat2, dat3, dat4, 0) 
 40          self._socket.send(s) 
 41          if opcode == 12: 
 42              return 
 43          s = self._socket.recv(4) 
 44          (status,) = struct.unpack('!h2x', s) 
 45          if status: 
 46              msg = "AIPS TV returned %d", status 
 47              raise IOError, msg 
 48          return 
 49   
 50 -    def _open(self): 
 51          """Open connection to the AIPS TV server.""" 
 52   
 53          self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
 54          self._socket.connect((self.host, self.port)) 
 55          self._send(11) 
 56          return 
 57   
 58 -    def _close(self): 
 59          """Close connection to the AIPS TV server.""" 
 60   
 61          self._socket.send(struct.pack('!6h', 12, 0, 0, 0, 0, 0)) 
 62          self._socket.close() 
 63          return 
 64   
 65 -    def running(self): 
 66          """Check if the AIPS TV server is running.""" 
 67   
 68          # Check by opening a connection to the TV. 
 69          try: 
 70              self._open(); 
 71          except: 
 72              return False 
 73   
 74          self._close() 
 75          return True 
 76   
 77 -    def exists(self): 
 78          """Alias for AIPSTV.running().""" 
 79   
 80          return self.running() 
 81   
 82 -    def start(self): 
 83          """Start the AIPS TV server.""" 
 84   
 85          # Check if we already started the AIPS TV. 
 86          if self._lock_pid and self._server_pid: 
 87              raise RuntimeError, "the AIPS TV has already been started" 
 88   
 89          # Create an environment for the AIPS TV processes. 
 90          env = os.environ.copy() 
 91          env['TVDEV'] = 'TVDEV01' 
 92          env['TVDEV01'] = 'sssin:localhost' 
 93   
 94          # Start the AIPS TV lock daemon. 
 95          file = env['LOAD'] + '/TVSERV.EXE' 
 96          self._lock_pid = os.spawnve(os.P_NOWAIT, file, ['TVSERVER'], env) 
 97   
 98          # Start the AIPS TV server. 
 99          file = env['LOAD'] + '/XAS' 
100          self._server_pid = os.spawnve(os.P_NOWAIT, file, ['XAS'], env) 
101   
102          # Wait until the TV server has been started. 
103          time.sleep(2) 
104          return 
105   
106 -    def clear(self): 
107          """Init the AIPS TV server.""" 
108   
109          self._open() 
110          self._send(15) 
111          self._close() 
112          return 
113   
114 -    def kill(self): 
115          """Close down the AIPS TV server.""" 
116   
117          self._open() 
118          self._socket.send(struct.pack('!6h', 18, 0, 0, 0, 0, 0)) 
119          self._socket.close() 
120   
121          # Kill of the zombies. 
122          waited = False 
123          if self._lock_pid: 
124              os.waitpid(self._lock_pid, 0) 
125              self._lock_pid = 0 
126              waited = True 
127              pass 
128          if self._server_pid: 
129              os.waitpid(self._server_pid, 0) 
130              self._server_pid = 0 
131              waited = True 
132              pass 
133          if not waited: 
134              # Take a nap to avoid confusing users with the output of 
135              # the dying processes. 
136              time.sleep(2) 
137   
138          return 
139   
140      pass                                # Class AIPSTV 
141