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# -*- coding: utf-8 -*-
"""
reporead_inotify command
Watches repo.files.tar.gz files for updates and parses them after a short delay
in order to catch all updates in a single bulk update.
Usage: ./manage.py reporead_inotify [path_template]
Where 'path_template' is an optional path_template for finding the
repo.files.tar.gz files. The form is '/srv/ftp/%(repo)s/os/%(arch)s/', which is
also the default template if none is specified. While 'repo' is not required to
be present in the path_template, note that 'arch' is so reporead can function
correctly.
"""
import logging
import multiprocessing
import os.path
import pyinotify
import sys
import threading
import time
from django.core.management.base import BaseCommand, CommandError
from django.db import connection
from main.models import Arch, Repo
from .reporead import read_repo
logging.basicConfig(
level=logging.WARNING,
format='%(asctime)s -> %(levelname)s: %(message)s',
datefmt='%Y-%m-%d %H:%M:%S',
stream=sys.stderr)
logger = logging.getLogger()
class Command(BaseCommand):
help = "Watch database files and run an update when necessary."
args = "[path_template]"
def handle(self, path_template=None, **options):
v = int(options.get('verbosity', 0))
if v == 0:
logger.level = logging.ERROR
elif v == 1:
logger.level = logging.INFO
elif v == 2:
logger.level = logging.DEBUG
if not path_template:
path_template = '/srv/ftp/%(repo)s/os/%(arch)s/'
self.path_template = path_template
notifier = self.setup_notifier()
logger.info('Entering notifier loop')
notifier.loop()
logger.info('Cancelling remaining threads...')
for thread in threading.enumerate():
if hasattr(thread, 'cancel'):
thread.cancel()
def setup_notifier(self):
'''Set up and configure the inotify machinery and logic.
This takes the provided or default path_template and builds a list of
directories we need to watch for database updates. It then validates
and passes these on to the various pyinotify pieces as necessary and
finally builds and returns a notifier object.'''
arches = Arch.objects.filter(agnostic=False)
repos = Repo.objects.all()
arch_path_map = dict((arch, None) for arch in arches)
all_paths = set()
total_paths = 0
for arch in arches:
combos = ({ 'repo': repo.name.lower(), 'arch': arch.name }
for repo in repos)
# take a python format string and generate all unique combinations
# of directories from it; using set() ensures we filter it down
paths = set(self.path_template % values for values in combos)
total_paths += len(paths)
all_paths |= paths
arch_path_map[arch] = paths
logger.info('Watching %d total paths', total_paths)
logger.debug(all_paths)
# sanity check- basically ensure every path we created from the
# template mapped to only one architecture
if total_paths != len(all_paths):
raise CommandError('path template did not uniquely '
'determine architecture for each file')
# this thread is done using the database; all future access is done in
# the spawned read_repo() processes, so close the otherwise completely
# idle connection.
connection.close()
# A proper atomic replacement of the database as done by rsync is type
# IN_MOVED_TO. repo-add/remove will finish with a IN_CLOSE_WRITE.
mask = pyinotify.IN_CLOSE_WRITE | pyinotify.IN_MOVED_TO
manager = pyinotify.WatchManager()
for name in all_paths:
manager.add_watch(name, mask)
handler = EventHandler(arch_paths=arch_path_map)
return pyinotify.Notifier(manager, handler)
class Database(object):
'''A object representing a pacman database on the filesystem. It stores
various bits of metadata and state representing the file path, when we last
updated, how long our delay is before performing the update, whether we are
updating now, etc.'''
def __init__(self, arch, path, delay=60.0):
self.arch = arch
self.path = path
self.delay = delay
self.mtime = None
self.last_import = None
self.update_thread = None
self.updating = False
self.run_again = False
self.lock = threading.Lock()
def _start_update_countdown(self):
self.update_thread = threading.Timer(self.delay, self.update)
logger.info('Starting %.1f second countdown to update %s',
self.delay, self.path)
self.update_thread.start()
def queue_for_update(self, mtime):
logger.debug('Queueing database %s...', self.path)
with self.lock:
self.mtime = mtime
if self.updating:
# store the fact that we will need to run it again
self.run_again = True
return
if self.update_thread:
self.update_thread.cancel()
self.update_thread = None
self._start_update_countdown()
def update(self):
logger.debug('Updating database %s...', self.path)
with self.lock:
self.last_import = time.time()
self.updating = True
try:
# invoke reporead's primary method. we do this in a separate
# process for memory conservation purposes; these processes grow
# rather large so it is best to free up the memory ASAP.
process = multiprocessing.Process(target=read_repo,
args=[self.arch, self.path, {}])
process.start()
process.join()
finally:
logger.debug('Done updating database %s.', self.path)
with self.lock:
self.update_thread = None
self.updating = False
if self.run_again:
self.run_again = False
self._start_update_countdown()
class EventHandler(pyinotify.ProcessEvent):
'''Our main event handler which listens for database change events. Because
we are watching the whole directory, we filter down and only look at those
events dealing with files databases.'''
def my_init(self, **kwargs):
self.databases = {}
self.arch_lookup = {}
# we really want a single path to arch mapping, so massage the data
arch_paths = kwargs['arch_paths']
for arch, paths in arch_paths.items():
self.arch_lookup.update((path.rstrip('/'), arch) for path in paths)
def process_default(self, event):
'''Primary event processing function which kicks off reporead timer
threads if a files database was updated.'''
if not event.name:
return
# screen to only the files we care about
if event.name.endswith('.files.tar.gz'):
path = event.pathname
stat = os.stat(path)
database = self.databases.get(path, None)
if database is None:
arch = self.arch_lookup.get(event.path, None)
if arch is None:
logger.warning(
'Could not determine arch for %s, skipping update',
path)
return
database = Database(arch, path)
self.databases[path] = database
database.queue_for_update(stat.st_mtime)
# vim: set ts=4 sw=4 et:
|
