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#!/usr/bin/python
# $Id$
'''Bcfg2.Server.Core provides the runtime support for bcfg2 modules'''
__revision__ = '$Revision$'
from os import stat
from stat import ST_MODE, S_ISDIR
from syslog import syslog, LOG_ERR
from time import time
import _fam
class GeneratorError(Exception):
pass
class PublishError(Exception):
pass
class fam(object):
'''The fam object is a set of callbacks for file alteration events'''
def __init__(self):
self.fm = _fam.open()
self.users = {}
self.handles = {}
def fileno(self):
return self.fm.fileno()
def AddMonitor(self, path, obj=None):
mode = stat(path)[ST_MODE]
if S_ISDIR(mode):
handle = self.fm.monitorDirectory(path, None)
else:
handle = self.fm.monitorFile(path, None)
self.handles[handle.requestID()] = handle
if obj != None:
self.users[handle.requestID()] = obj
return handle.requestID()
def HandleEvent(self):
event = self.fm.nextEvent()
reqid = event.requestID
if self.users.has_key(reqid):
self.users[reqid].HandleEvent(event)
class PublishedValue(object):
def __init__(self, owner, key, value):
self.owner = owner
self.key = key
self.value = value
def Update(self, owner, value):
if owner != self.owner:
raise PublishError, (self.key, owner)
self.value = value
class Core(object):
def __init__(self, repository, structures, generators):
object.__init__(self)
self.datastore = repository
self.fam = fam()
self.pubspace = {}
self.structures = []
self.cron = {}
for structure in structures:
try:
mod = getattr(__import__("Bcfg2.Server.Structures.%s" %
(structure)).Server.Structures, structure)
except ImportError:
syslog(LOG_ERR, "Failed to load structure %s" % (structure))
continue
struct = getattr(mod, structure)
self.structures.append(struct(self, self.datastore))
self.generators = []
for generator in generators:
try:
mod = getattr(__import__("Bcfg2.Server.Generators.%s" %
(generator)).Server.Generators, generator)
except ImportError:
syslog(LOG_ERR, 'Failed to load generator %s' % (generator))
continue
gen = getattr(mod, generator)
self.generators.append(gen(self, self.datastore))
# we need to inventory and setup generators
# Process generator requirements
for gen in self.generators:
for prq in gen.__requires__:
if not self.pubspace.has_key(prq):
raise GeneratorError, (gen.name, prq)
gen.CompleteSetup()
def PublishValue(self, owner, key, value):
if not self.pubspace.has_key(key):
# This is a new entry
self.pubspace[key] = PublishedValue(owner, key, value)
else:
# This is an old entry. Update can fai
try:
self.pubspace[key].Update(owner, value)
except PublishError:
syslog(LOG_ERR, "Publish conflict for %s. Owner %s, Modifier %s"%
(key, self.pubspace[key].owner, owner))
def ReadValue(self, key):
if self.pubspace.has_key(key):
return self.pubspace[key].value
raise KeyError, key
def GetStructures(self, metadata):
return reduce(lambda x, y:x+y,
[z.Construct(metadata) for z in self.structures])
def BindStructure(self, structure, metadata):
for entry in [x for x in structure.getchildren() if x.tag not in ['SymLink', 'Directory']]:
try:
self.Bind(entry, metadata)
except KeyError, k:
syslog(LOG_ERR, "Unable to locate %s"%k)
def Bind(self, entry, metadata):
g = [x for x in self.generators if
x.__provides__.get(entry.tag, {}).has_key(entry.attrib['name'])]
if len(g) == 1:
return g[0].__provides__[entry.tag][entry.attrib['name']](entry, metadata)
elif len(g) > 1:
print "Data Integrity error for %s %s" % (entry.tag, entry.attrib['name'])
else:
for g in self.generators:
if hasattr(g, "FindHandler"):
try:
return g.FindHandler(entry)(entry, metadata)
except:
print g, "failed"
raise KeyError, (entry.tag, entry.attrib['name'])
def RunCronTasks(self):
g = [x for x in self.generators if x.__croninterval__]
for generator in g:
t = time()
if ((t - self.cron.get(generator, 0)) > generator.__croninterval__):
generator.Cron()
self.cron[generator] = t
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