Coverage for master/buildbot/util/maildir : 76%

# This file is part of Buildbot.  Buildbot is free software: you can 

# redistribute it and/or modify it under the terms of the GNU General Public 

# License as published by the Free Software Foundation, version 2. 

# 

# This program is distributed in the hope that it will be useful, but WITHOUT 

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 

# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more 

# details. 

# 

# You should have received a copy of the GNU General Public License along with 

# this program; if not, write to the Free Software Foundation, Inc., 51 

# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 

# 

# Copyright Buildbot Team Members 

# This is a class which watches a maildir for new messages. It uses the 

# linux dirwatcher API (if available) to look for new files. The 

# .messageReceived method is invoked with the filename of the new message, 

# relative to the top of the maildir (so it will look like "new/blahblah"). 

import os 

from twisted.python import log, runtime 

from twisted.application import service, internet 

from twisted.internet import reactor, defer 

dnotify = None 

try: 

    import dnotify 

except: 

    log.msg("unable to import dnotify, so Maildir will use polling instead") 

class NoSuchMaildir(Exception): 

    pass 

class MaildirService(service.MultiService): 

    pollinterval = 10  # only used if we don't have DNotify 

    def __init__(self, basedir=None): 

        service.MultiService.__init__(self) 

        if basedir: 

            self.setBasedir(basedir) 

        self.files = [] 

        self.dnotify = None 

    def setBasedir(self, basedir): 

        # some users of MaildirService (scheduler.Try_Jobdir, in particular) 

        # don't know their basedir until setServiceParent, since it is 

        # relative to the buildmaster's basedir. So let them set it late. We 

        # don't actually need it until our own startService. 

        self.basedir = basedir 

        self.newdir = os.path.join(self.basedir, "new") 

        self.curdir = os.path.join(self.basedir, "cur") 

    def startService(self): 

        service.MultiService.startService(self) 

        if not os.path.isdir(self.newdir) or not os.path.isdir(self.curdir): 

            raise NoSuchMaildir("invalid maildir '%s'" % self.basedir) 

        try: 

            if dnotify: 

                # we must hold an fd open on the directory, so we can get 

                # notified when it changes. 

                self.dnotify = dnotify.DNotify(self.newdir, 

                                               self.dnotify_callback, 

                                               [dnotify.DNotify.DN_CREATE]) 

        except (IOError, OverflowError): 

            # IOError is probably linux<2.4.19, which doesn't support 

            # dnotify. OverflowError will occur on some 64-bit machines 

            # because of a python bug 

            log.msg("DNotify failed, falling back to polling") 

        if not self.dnotify: 

            t = internet.TimerService(self.pollinterval, self.poll) 

            t.setServiceParent(self) 

        self.poll() 

    def dnotify_callback(self): 

        log.msg("dnotify noticed something, now polling") 

        # give it a moment. I found that qmail had problems when the message 

        # was removed from the maildir instantly. It shouldn't, that's what 

        # maildirs are made for. I wasn't able to eyeball any reason for the 

        # problem, and safecat didn't behave the same way, but qmail reports 

        # "Temporary_error_on_maildir_delivery" (qmail-local.c:165, 

        # maildir_child() process exited with rc not in 0,2,3,4). Not sure 

        # why, and I'd have to hack qmail to investigate further, so it's 

        # easier to just wait a second before yanking the message out of new/ 

        reactor.callLater(0.1, self.poll) 

    def stopService(self): 

        if self.dnotify: 

            self.dnotify.remove() 

            self.dnotify = None 

        return service.MultiService.stopService(self) 

    @defer.inlineCallbacks 

    def poll(self): 

        assert self.basedir 

        # see what's new 

        for f in self.files: 

            if not os.path.isfile(os.path.join(self.newdir, f)): 

                self.files.remove(f) 

        newfiles = [] 

        for f in os.listdir(self.newdir): 

            if not f in self.files: 

                newfiles.append(f) 

        self.files.extend(newfiles) 

        for n in newfiles: 

            try: 

                yield self.messageReceived(n) 

            except: 

                log.msg("while reading '%s' from maildir '%s':" % (n, self.basedir)) 

                log.err() 

    def moveToCurDir(self, filename): 

        if runtime.platformType == "posix": 

            # open the file before moving it, because I'm afraid that once 

            # it's in cur/, someone might delete it at any moment 

            path = os.path.join(self.newdir, filename) 

            f = open(path, "r") 

            os.rename(os.path.join(self.newdir, filename), 

                      os.path.join(self.curdir, filename)) 

        elif runtime.platformType == "win32": 

            # do this backwards under windows, because you can't move a file 

            # that somebody is holding open. This was causing a Permission 

            # Denied error on bear's win32-twisted1.3 buildslave. 

            os.rename(os.path.join(self.newdir, filename), 

                      os.path.join(self.curdir, filename)) 

            path = os.path.join(self.curdir, filename) 

            f = open(path, "r") 

        return f 

    def messageReceived(self, filename): 

        raise NotImplementedError