slapos/recipe/librecipe/execute.py

   1 import sys
   2 import os
   3 import signal
   4 import subprocess
   5 import time
   6
   7 import inotifyx
   8
   9 def _wait_files_creation(file_list):
  10   # Etablish a list of directory and subfiles
  11   directories = dict()
  12   for dirname, filename in [os.path.split(f) for f in file_list]:
  13     directories.setdefault(dirname, dict())
  14     directories[dirname][filename] = False
  15
  16   def all_files_exists():
  17     return all([all(files.values()) for files in directories.values()])
  18
  19   fd = inotifyx.init()
  20   try:
  21     # Watch every directories where the file are
  22     watchdescriptors = dict()
  23     for dirname in directories.keys():
  24       wd = inotifyx.add_watch(fd,
  25                               dirname,
  26                               inotifyx.IN_CREATE | inotifyx.IN_DELETE)
  27       watchdescriptors[wd] = dirname
  28
  29     # Set to True the file wich exists
  30     for dirname, filename in [os.path.split(f) for f in file_list]:
  31       directories[dirname][filename] = os.path.exists(os.path.join(dirname,
  32                                                                    filename))
  33     # Let's wait for every file creation
  34     while not all_files_exists():
  35       events_list = inotifyx.get_events(fd)
  36       for event in events_list:
  37         dirname = watchdescriptors[event.wd]
  38         if event.name in directories[dirname]:
  39           # One of watched file was created or deleted
  40           if event.mask & inotifyx.IN_DELETE:
  41             directories[dirname][event.name] = False
  42           else:
  43             directories[dirname][event.name] = True
  44
  45   finally:
  46     os.close(fd)
  47
  48 def execute(args):
  49   """Portable execution with process replacement"""
  50   # XXX: Kept for backward compatibility
  51   generic_exec([args, None, None])
  52
  53 def execute_wait(args):
  54   """Execution but after all files in args[1] exists"""
  55   # XXX: Kept for backward compatibility
  56   generic_exec([args[0], args[1], None])
  57
  58
  59 child_pg = None
  60
  61
  62 def executee(args):
  63   """Portable execution with process replacement and environment manipulation"""
  64   # XXX: Kept for backward compatibility
  65   generic_exec([args[0], None, args[1]])
  66
  67 def executee_wait(args):
  68   """Portable execution with process replacement and environment manipulation"""
  69   # XXX: Kept for backward compatibility
  70   generic_exec(args)
  71
  72 def generic_exec(args):
  73   exec_list = list(args[0])
  74   file_list = args[1]
  75   environment_overriding = args[2]
  76
  77   exec_env = os.environ.copy()
  78   if environment_overriding is not None:
  79       exec_env.update(environment_overriding)
  80
  81   if file_list is not None:
  82       _wait_files_creation(file_list)
  83
  84   os.execve(exec_list[0], exec_list + sys.argv[1:], exec_env)
  85
  86 def sig_handler(signal, frame):
  87   print 'Received signal %r, killing children and exiting' % signal
  88   if child_pg is not None:
  89     os.killpg(child_pg, signal.SIGHUP)
  90     os.killpg(child_pg, signal.SIGTERM)
  91   sys.exit(0)
  92
  93 signal.signal(signal.SIGINT, sig_handler)
  94 signal.signal(signal.SIGQUIT, sig_handler)
  95 signal.signal(signal.SIGTERM, sig_handler)
  96
  97
  98 def execute_with_signal_translation(args):
  99   """Run process as children and translate from SIGTERM to another signal"""
 100   child = subprocess.Popen(args, close_fds=True, preexec_fn=os.setsid)
 101   child_pg = child.pid
 102   try:
 103     print 'Process %r started' % args
 104     while True:
 105       time.sleep(10)
 106   finally:
 107     os.killpg(child_pg, signal.SIGHUP)
 108     os.killpg(child_pg, signal.SIGTERM)