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