Source Code for Module buildbot.changes.maildir

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 13  # 
 14  # Copyright Buildbot Team Members 
 15   
 16   
 17  # This is a class which watches a maildir for new messages. It uses the 
 18  # linux dirwatcher API (if available) to look for new files. The 
 19  # .messageReceived method is invoked with the filename of the new message, 
 20  # relative to the top of the maildir (so it will look like "new/blahblah"). 
 21   
 22  import os 
 23  from twisted.python import log 
 24  from twisted.application import service, internet 
 25  from twisted.internet import reactor 
 26  dnotify = None 
 27  try: 
 28      import dnotify 
 29  except: 
 30      # I'm not actually sure this log message gets recorded 
 31      log.msg("unable to import dnotify, so Maildir will use polling instead") 
 32   
 33 -class NoSuchMaildir(Exception): 
 34      pass 
 35   
 36 -class MaildirService(service.MultiService): 
 37      """I watch a maildir for new messages. I should be placed as the service 
 38      child of some MultiService instance. When running, I use the linux 
 39      dirwatcher API (if available) or poll for new files in the 'new' 
 40      subdirectory of my maildir path. When I discover a new message, I invoke 
 41      my .messageReceived() method with the short filename of the new message, 
 42      so the full name of the new file can be obtained with 
 43      os.path.join(maildir, 'new', filename). messageReceived() should be 
 44      overridden by a subclass to do something useful. I will not move or 
 45      delete the file on my own: the subclass's messageReceived() should 
 46      probably do that. 
 47      """ 
 48      pollinterval = 10  # only used if we don't have DNotify 
 49   
 50 -    def __init__(self, basedir=None): 
 51          """Create the Maildir watcher. BASEDIR is the maildir directory (the 
 52          one which contains new/ and tmp/) 
 53          """ 
 54          service.MultiService.__init__(self) 
 55          self.basedir = basedir 
 56          self.files = [] 
 57          self.dnotify = None 
 58   
 59 -    def setBasedir(self, basedir): 
 60          # some users of MaildirService (scheduler.Try_Jobdir, in particular) 
 61          # don't know their basedir until setServiceParent, since it is 
 62          # relative to the buildmaster's basedir. So let them set it late. We 
 63          # don't actually need it until our own startService. 
 64          self.basedir = basedir 
 65   
 66 -    def startService(self): 
 67          service.MultiService.startService(self) 
 68          self.newdir = os.path.join(self.basedir, "new") 
 69          if not os.path.isdir(self.basedir) or not os.path.isdir(self.newdir): 
 70              raise NoSuchMaildir("invalid maildir '%s'" % self.basedir) 
 71          try: 
 72              if dnotify: 
 73                  # we must hold an fd open on the directory, so we can get 
 74                  # notified when it changes. 
 75                  self.dnotify = dnotify.DNotify(self.newdir, 
 76                                                 self.dnotify_callback, 
 77                                                 [dnotify.DNotify.DN_CREATE]) 
 78          except (IOError, OverflowError): 
 79              # IOError is probably linux<2.4.19, which doesn't support 
 80              # dnotify. OverflowError will occur on some 64-bit machines 
 81              # because of a python bug 
 82              log.msg("DNotify failed, falling back to polling") 
 83          if not self.dnotify: 
 84              t = internet.TimerService(self.pollinterval, self.poll) 
 85              t.setServiceParent(self) 
 86          self.poll() 
 87   
 88 -    def dnotify_callback(self): 
 89          log.msg("dnotify noticed something, now polling") 
 90   
 91          # give it a moment. I found that qmail had problems when the message 
 92          # was removed from the maildir instantly. It shouldn't, that's what 
 93          # maildirs are made for. I wasn't able to eyeball any reason for the 
 94          # problem, and safecat didn't behave the same way, but qmail reports 
 95          # "Temporary_error_on_maildir_delivery" (qmail-local.c:165, 
 96          # maildir_child() process exited with rc not in 0,2,3,4). Not sure 
 97          # why, and I'd have to hack qmail to investigate further, so it's 
 98          # easier to just wait a second before yanking the message out of new/ 
 99   
100          reactor.callLater(0.1, self.poll) 
101   
102   
103 -    def stopService(self): 
104          if self.dnotify: 
105              self.dnotify.remove() 
106              self.dnotify = None 
107          return service.MultiService.stopService(self) 
108   
109 -    def poll(self): 
110          assert self.basedir 
111          # see what's new 
112          for f in self.files: 
113              if not os.path.isfile(os.path.join(self.newdir, f)): 
114                  self.files.remove(f) 
115          newfiles = [] 
116          for f in os.listdir(self.newdir): 
117              if not f in self.files: 
118                  newfiles.append(f) 
119          self.files.extend(newfiles) 
120          # TODO: sort by ctime, then filename, since safecat uses a rather 
121          # fine-grained timestamp in the filename 
122          for n in newfiles: 
123              # TODO: consider catching exceptions in messageReceived 
124              self.messageReceived(n) 
125   
126 -    def messageReceived(self, filename): 
127          """Called when a new file is noticed. Will call 
128          self.parent.messageReceived() with a path relative to maildir/new. 
129          Should probably be overridden in subclasses.""" 
130          self.parent.messageReceived(filename) 
131