Index: trunk/packages/sipb-xen-base/files/usr/share/python-support/sipb-xen-base/invirt/__init__.py =================================================================== --- trunk/packages/sipb-xen-base/files/usr/share/python-support/sipb-xen-base/invirt/__init__.py (revision 1197) +++ (revision ) @@ -1,27 +1,0 @@ -'''Invirt - a virtualization management system - -Invirt was developed at the Student Information Processing Board of -the Massachusetts Institute of Technology. See http://xvm.mit.edu/. - -Invirt is free software available under the GNU GPL, version 2 or later. -Consult the source files for details. -''' - -# Invirt 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, either version 2 of the License, or (at your -# option) any later version. - -# Invirt 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 Invirt. If not, see . - -__author__ = 'MIT SIPB' -__version__ = '0.1' -__copyright__ = 'Copyright (c) 2008 MIT SIPB' - -# vim:et:sw=4:ts=4 Index: trunk/packages/sipb-xen-base/files/usr/share/python-support/sipb-xen-base/invirt/common.py =================================================================== --- trunk/packages/sipb-xen-base/files/usr/share/python-support/sipb-xen-base/invirt/common.py (revision 1197) +++ (revision ) @@ -1,58 +1,0 @@ -from __future__ import with_statement - -import unittest -from fcntl import flock, LOCK_EX, LOCK_SH, LOCK_UN -import contextlib as clib - -class struct(object): - 'A simple namespace object.' - def __init__(self, d = {}, **kwargs): - 'd is the dictionary to update my __dict__ with.' - self.__dict__.update(d) - self.__dict__.update(kwargs) - -def dicts2struct(x): - """ - Given a tree of lists/dicts, perform a deep traversal to transform all the - dicts to structs. - """ - if type(x) == dict: - return struct((k, dicts2struct(v)) for k,v in x.iteritems()) - elif type(x) == list: - return [dicts2struct(v) for v in x] - else: - return x - -@clib.contextmanager -def lock_file(path, exclusive = True): - with clib.closing(file(path, 'w')) as f: - if exclusive: - locktype = LOCK_EX - else: - locktype = LOCK_SH - flock(f, locktype) - try: - yield - finally: - flock(f, LOCK_UN) - -# -# Tests. -# - -class common_tests(unittest.TestCase): - def test_dicts2structs(self): - dicts = { - 'atom': 0, - 'dict': { 'atom': 'atom', 'list': [1,2,3] }, - 'list': [ 'atom', {'key': 'value'} ] - } - structs = dicts2struct(dicts) - self.assertEqual(structs.atom, dicts['atom']) - self.assertEqual(structs.dict.atom, dicts['dict']['atom']) - self.assertEqual(structs.dict.list, dicts['dict']['list']) - self.assertEqual(structs.list[0], dicts['list'][0]) - self.assertEqual(structs.list[1].key, dicts['list'][1]['key']) - -if __name__ == '__main__': - unittest.main() Index: trunk/packages/sipb-xen-base/files/usr/share/python-support/sipb-xen-base/invirt/config.py =================================================================== --- trunk/packages/sipb-xen-base/files/usr/share/python-support/sipb-xen-base/invirt/config.py (revision 1197) +++ (revision ) @@ -1,91 +1,0 @@ -from __future__ import with_statement - -import json -from invirt.common import * -from os import rename -from os.path import getmtime -from contextlib import closing - -default_src_path = '/etc/invirt/master.yaml' -default_cache_path = '/var/lib/invirt/cache.json' -lock_path = '/var/lib/invirt/cache.lock' - -def load(src_path = default_src_path, - cache_path = default_cache_path, - force_refresh = False): - """ - Try loading the configuration from the faster-to-load JSON cache at - cache_path. If it doesn't exist or is outdated, load the configuration - instead from the original YAML file at src_path and regenerate the cache. - I assume I have the permissions to write to the cache directory. - """ - - # Namespace container for state variables, so that they can be updated by - # closures. - ns = struct() - - if force_refresh: - do_refresh = True - else: - src_mtime = getmtime(src_path) - try: cache_mtime = getmtime(cache_path) - except OSError: do_refresh = True - else: do_refresh = src_mtime + 1 >= cache_mtime - - # We chose not to simply say - # - # do_refresh = src_mtime >= cache_time - # - # because between the getmtime(src_path) and the time the cache is - # rewritten, the master configuration may have been updated, so future - # checks here would find a cache with a newer mtime than the master - # (and thus treat the cache as containing the latest version of the - # master). The +1 means that for at least a full second following the - # update to the master, this function will refresh the cache, giving us - # 1 second to write the cache. Note that if it takes longer than 1 - # second to write the cache, then this situation could still arise. - # - # The getmtime calls should logically be part of the same transaction - # as the rest of this function (cache read + conditional cache - # refresh), but to wrap everything in an flock would cause the - # following cache read to be less streamlined. - - if not do_refresh: - # Try reading from the cache first. This must be transactionally - # isolated from concurrent writes to prevent reading an incomplete - # (changing) version of the data (but the transaction can share the - # lock with other concurrent reads). This isolation is accomplished - # using an atomic filesystem rename in the refreshing stage. - try: - with closing(file(cache_path)) as f: - ns.cfg = json.read(f.read()) - except: do_refresh = True - - if do_refresh: - # Atomically reload the source and regenerate the cache. The read and - # write must be a single transaction, or a stale version may be - # written (if another read/write of a more recent configuration - # is interleaved). The final atomic rename is to keep this - # transactionally isolated from the above cache read. If we fail to - # acquire the lock, just try to load the master configuration. - import yaml - try: loader = yaml.CSafeLoader - except: loader = yaml.SafeLoader - try: - with lock_file(lock_path): - with closing(file(src_path)) as f: - ns.cfg = yaml.load(f, loader) - try: - with closing(file(cache_path + '.tmp', 'w')) as f: - f.write(json.write(ns.cfg)) - except: pass # silent failure - else: rename(cache_path + '.tmp', cache_path) - except IOError: - with closing(file(src_path)) as f: - ns.cfg = yaml.load(f, loader) - return ns.cfg - -dicts = load() -structs = dicts2struct(dicts) - -# vim:et:sw=4:ts=4 Index: trunk/packages/sipb-xen-base/files/usr/share/python-support/sipb-xen-base/invirt/remote.py =================================================================== --- trunk/packages/sipb-xen-base/files/usr/share/python-support/sipb-xen-base/invirt/remote.py (revision 1197) +++ (revision ) @@ -1,19 +1,0 @@ -from subprocess import PIPE, Popen -from invirt.config import structs as config -import yaml - -def bcast(cmd, hosts = [h.hostname for h in config.hosts]): - """ - Given a command and a list of hostnames or IPs, issue the command to all - the nodes and return a list of (host, output) pairs (the order should be - the same as the order of the hosts). - """ - pipes = [(host, - Popen(['remctl', host, 'remote', 'web', cmd], stdout=PIPE)) - for host in hosts] - outputs = [(s, p.communicate()[0]) for (s, p) in pipes] - for (s, p) in pipes: - if p.returncode != 0: - raise RuntimeError("remctl to host %s returned non-zero exit status %d" - % (s, p.returncode)) - return [(s, yaml.load(o, yaml.CSafeLoader)) for (s, o) in outputs]