zeroinstall/injector/background.py

   1 """
   2 Check for updates in a background process. If we can start a program immediately, but some of our information
   3 is rather old (longer that the L{policy.Policy.freshness} threshold) then we run it anyway, and check for updates using a new
   4 process that runs quietly in the background.
   5
   6 This avoids the need to annoy people with a 'checking for updates' box when they're trying to run things.
   7 """
   8
   9 # Copyright (C) 2009, Thomas Leonard
  10 # See the README file for details, or visit http://0install.net.
  11
  12 from zeroinstall import _
  13 import sys, os
  14 from logging import info, warn
  15 from zeroinstall.support import tasks
  16 from zeroinstall.injector.iface_cache import iface_cache
  17 from zeroinstall.injector import handler
  18
  19 def _escape_xml(s):
  20         return s.replace('&', '&amp;').replace('<', '&lt;')
  21
  22 def _exec_gui(uri, *args):
  23         os.execvp('0launch', ['0launch', '--download-only', '--gui'] + list(args) + [uri])
  24
  25 class _NetworkState:
  26         NM_STATE_UNKNOWN = 0
  27         NM_STATE_ASLEEP = 1
  28         NM_STATE_CONNECTING = 2
  29         NM_STATE_CONNECTED = 3
  30         NM_STATE_DISCONNECTED = 4
  31
  32 class BackgroundHandler(handler.Handler):
  33         """A Handler for non-interactive background updates. Runs the GUI if interaction is required."""
  34         def __init__(self, title, root):
  35                 handler.Handler.__init__(self)
  36                 self.title = title
  37                 self.notification_service = None
  38                 self.network_manager = None
  39                 self.notification_service_caps = []
  40                 self.root = root        # If we need to confirm any keys, run the GUI on this
  41
  42                 try:
  43                         import dbus
  44                         import dbus.glib
  45                 except Exception, ex:
  46                         info(_("Failed to import D-BUS bindings: %s"), ex)
  47                         return
  48
  49                 try:
  50                         session_bus = dbus.SessionBus()
  51                         remote_object = session_bus.get_object('org.freedesktop.Notifications',
  52                                                                 '/org/freedesktop/Notifications')
  53
  54                         self.notification_service = dbus.Interface(remote_object,
  55                                                         'org.freedesktop.Notifications')
  56
  57                         # The Python bindings insist on printing a pointless introspection
  58                         # warning to stderr if the service is missing. Force it to be done
  59                         # now so we can skip it
  60                         old_stderr = sys.stderr
  61                         sys.stderr = None
  62                         try:
  63                                 self.notification_service_caps = [str(s) for s in
  64                                                 self.notification_service.GetCapabilities()]
  65                         finally:
  66                                 sys.stderr = old_stderr
  67                 except Exception, ex:
  68                         info(_("No D-BUS notification service available: %s"), ex)
  69
  70                 try:
  71                         system_bus = dbus.SystemBus()
  72                         remote_object = system_bus.get_object('org.freedesktop.NetworkManager',
  73                                                                 '/org/freedesktop/NetworkManager')
  74
  75                         self.network_manager = dbus.Interface(remote_object,
  76                                                         'org.freedesktop.NetworkManager')
  77                 except Exception, ex:
  78                         info(_("No D-BUS network manager service available: %s"), ex)
  79
  80         def get_network_state(self):
  81                 if self.network_manager:
  82                         try:
  83                                 return self.network_manager.state()
  84                         except Exception, ex:
  85                                 warn(_("Error getting network state: %s"), ex)
  86                 return _NetworkState.NM_STATE_UNKNOWN
  87
  88         def confirm_trust_keys(self, interface, sigs, iface_xml):
  89                 """Run the GUI if we need to confirm any keys."""
  90                 info(_("Can't update interface; signature not yet trusted. Running GUI..."))
  91                 _exec_gui(self.root, '--refresh', '--download-only', '--systray')
  92
  93         def report_error(self, exception, tb = None):
  94                 from zeroinstall.injector import download
  95                 if isinstance(exception, download.DownloadError):
  96                         tb = None
  97
  98                 if tb:
  99                         import traceback
 100                         details = '\n' + '\n'.join(traceback.format_exception(type(exception), exception, tb))
 101                 else:
 102                         details = str(exception)
 103                 self.notify("Zero Install", _("Error updating %(title)s: %(details)s") % {'title': self.title, 'details': details.replace('<', '&lt;')})
 104
 105         def notify(self, title, message, timeout = 0, actions = []):
 106                 """Send a D-BUS notification message if possible. If there is no notification
 107                 service available, log the message instead."""
 108                 if not self.notification_service:
 109                         info('%s: %s', title, message)
 110                         return None
 111
 112                 LOW = 0
 113                 NORMAL = 1
 114                 CRITICAL = 2
 115
 116                 import dbus.types
 117
 118                 hints = {}
 119                 if actions:
 120                         hints['urgency'] = dbus.types.Byte(NORMAL)
 121                 else:
 122                         hints['urgency'] = dbus.types.Byte(LOW)
 123
 124                 return self.notification_service.Notify('Zero Install',
 125                         0,              # replaces_id,
 126                         '',             # icon
 127                         _escape_xml(title),
 128                         _escape_xml(message),
 129                         actions,
 130                         hints,
 131                         timeout * 1000)
 132
 133         def have_actions_support(self):
 134                 return 'actions' in self.notification_service_caps
 135
 136 def _detach():
 137         """Fork a detached grandchild.
 138         @return: True if we are the original."""
 139         child = os.fork()
 140         if child:
 141                 pid, status = os.waitpid(child, 0)
 142                 assert pid == child
 143                 return True
 144
 145         # The calling process might be waiting for EOF from its child.
 146         # Close our stdout so we don't keep it waiting.
 147         # Note: this only fixes the most common case; it could be waiting
 148         # on any other FD as well. We should really use gobject.spawn_async
 149         # to close *all* FDs.
 150         null = os.open('/dev/null', os.O_RDWR)
 151         os.dup2(null, 1)
 152         os.close(null)
 153
 154         grandchild = os.fork()
 155         if grandchild:
 156                 os._exit(0)     # Parent's waitpid returns and grandchild continues
 157
 158         return False
 159
 160 def _check_for_updates(policy, verbose):
 161         root_iface = iface_cache.get_interface(policy.root).get_name()
 162
 163         policy.handler = BackgroundHandler(root_iface, policy.root)
 164
 165         info(_("Checking for updates to '%s' in a background process"), root_iface)
 166         if verbose:
 167                 policy.handler.notify("Zero Install", _("Checking for updates to '%s'...") % root_iface, timeout = 1)
 168
 169         network_state = policy.handler.get_network_state()
 170         if network_state != _NetworkState.NM_STATE_CONNECTED:
 171                 info(_("Not yet connected to network (status = %d). Sleeping for a bit..."), network_state)
 172                 import time
 173                 time.sleep(120)
 174                 if network_state in (_NetworkState.NM_STATE_DISCONNECTED, _NetworkState.NM_STATE_ASLEEP):
 175                         info(_("Still not connected to network. Giving up."))
 176                         sys.exit(1)
 177         else:
 178                 info(_("NetworkManager says we're on-line. Good!"))
 179
 180         policy.freshness = 0                    # Don't bother trying to refresh when getting the interface
 181         refresh = policy.refresh_all()          # (causes confusing log messages)
 182         policy.handler.wait_for_blocker(refresh)
 183
 184         # We could even download the archives here, but for now just
 185         # update the interfaces.
 186
 187         if not policy.need_download():
 188                 if verbose:
 189                         policy.handler.notify("Zero Install", _("No updates to download."), timeout = 1)
 190                 sys.exit(0)
 191
 192         if not policy.handler.have_actions_support():
 193                 # Can't ask the user to choose, so just notify them
 194                 # In particular, Ubuntu/Jaunty doesn't support actions
 195                 policy.handler.notify("Zero Install",
 196                                       _("Updates ready to download for '%s'.") % root_iface,
 197                                       timeout = 1)
 198                 _exec_gui(policy.root, '--refresh', '--download-only', '--systray')
 199                 sys.exit(1)
 200
 201         notification_closed = tasks.Blocker("wait for notification response")
 202
 203         def _NotificationClosed(nid, *unused):
 204                 if nid != our_question: return
 205                 notification_closed.trigger()
 206
 207         def _ActionInvoked(nid, action):
 208                 if nid != our_question: return
 209                 if action == 'download':
 210                         _exec_gui(policy.root)
 211                 notification_closed.trigger()
 212
 213         policy.handler.notification_service.connect_to_signal('NotificationClosed', _NotificationClosed)
 214         policy.handler.notification_service.connect_to_signal('ActionInvoked', _ActionInvoked)
 215
 216         our_question = policy.handler.notify("Zero Install", _("Updates ready to download for '%s'.") % root_iface,
 217                                 actions = ['download', 'Download'])
 218
 219         policy.handler.wait_for_blocker(notification_closed)
 220
 221 def spawn_background_update(policy, verbose):
 222         """Spawn a detached child process to check for updates.
 223         @param policy: policy containing interfaces to update
 224         @type policy: L{policy.Policy}
 225         @param verbose: whether to notify the user about minor events
 226         @type verbose: bool"""
 227         # Mark all feeds as being updated. Do this before forking, so that if someone is
 228         # running lots of 0launch commands in series on the same program we don't start
 229         # huge numbers of processes.
 230         for x in policy.implementation:
 231                 iface_cache.mark_as_checking(x.uri)                     # Main feed
 232                 for f in policy.usable_feeds(x):
 233                         iface_cache.mark_as_checking(f.uri)             # Extra feeds
 234
 235         if _detach():
 236                 return
 237
 238         try:
 239                 try:
 240                         _check_for_updates(policy, verbose)
 241                 except SystemExit:
 242                         raise
 243                 except:
 244                         import traceback
 245                         traceback.print_exc()
 246                         sys.stdout.flush()
 247         finally:
 248                 os._exit(1)