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'''Bcfg2.Server.Core provides the runtime support for bcfg2 modules'''
__revision__ = '$Revision$'
from os import stat
from stat import ST_MODE, S_ISDIR
from sys import exc_info
from syslog import syslog, LOG_ERR, LOG_INFO
from traceback import extract_tb
from time import time
from ConfigParser import ConfigParser
from elementtree.ElementTree import Element
from Bcfg2.Server.Plugin import PluginInitError, PluginExecutionError
from Bcfg2.Server.Metadata import MetadataStore, MetadataConsistencyError
from Bcfg2.Server.Statistics import Statistics
class CoreInitError(Exception):
'''This error is raised when the core cannot be initialized'''
pass
class FamFam(object):
'''The fam object is a set of callbacks for file alteration events (FAM support)'''
def __init__(self):
object.__init__(self)
self.fm = _fam.open()
self.users = {}
self.handles = {}
def fileno(self):
'''return fam file handle number'''
return self.fm.fileno()
def AddMonitor(self, path, obj):
'''add a monitor to path, installing a callback to obj.HandleEvent'''
mode = stat(path)[ST_MODE]
if S_ISDIR(mode):
handle = self.fm.monitorDirectory(path, None)
#print "adding callback for directory %s to %s, handle :%s:" % ( path, obj, handle.requestID())
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):
'''Route a fam event to the proper callback'''
event = self.fm.nextEvent()
reqid = event.requestID
if self.users.has_key(reqid):
#print "dispatching event %s %s to obj %s handle :%s:" % (event.code2str(), event.filename, self.users[reqid], event.requestID)
self.users[reqid].HandleEvent(event)
def Service(self):
'''Handle all fam work'''
while self.fm.pending():
self.HandleEvent()
class GaminEvent(object):
'''This class provides an event analogous to python-fam events based on gamin sources'''
def __init__(self, request_id, filename, code):
action_map = {GAMCreated: 'created', GAMExists: 'exists', GAMChanged: 'changed',
GAMDeleted: 'deleted', GAMEndExist: 'endExist'}
self.requestID = request_id
self.filename = filename
if action_map.has_key(code):
self.action = action_map[code]
def code2str(self):
'''return static code for event'''
return self.action
class GaminFam(object):
'''The fam object is a set of callbacks for file alteration events (Gamin support)'''
def __init__(self):
object.__init__(self)
self.mon = WatchMonitor()
self.handles = {}
self.counter = 0
def fileno(self):
'''return fam file handle number'''
return self.mon.get_fd()
def dispatch(self, path, action, request_id):
'''find the right object to dispatch to'''
if self.handles.has_key(request_id):
evt = GaminEvent(request_id, path, action)
#print "e %s %s to obj %s handle :%s:" % (evt.code2str(), evt.filename,
# self.handles[request_id], evt.requestID)
self.handles[request_id].HandleEvent(evt)
else:
print "got crazy event for nonexistant handle %s" % request_id
def AddMonitor(self, path, obj):
'''add a monitor to path, installing a callback to obj.HandleEvent'''
handle = self.counter
self.counter += 1
mode = stat(path)[ST_MODE]
if S_ISDIR(mode):
self.mon.watch_directory(path, self.dispatch, handle)
#print "adding callback for directory %s to %s, handle :%s:" % ( path, obj, handle.requestID())
else:
self.mon.watch_file(path, self.dispatch, handle)
self.handles[handle] = obj
return handle
def HandleEvent(self):
'''Call Gamin, which will call the callback'''
self.mon.handle_one_event()
def Service(self):
'''Handle any pending Gamin work'''
while self.mon.event_pending():
self.mon.handle_one_event()
try:
from gamin import WatchMonitor, GAMCreated, GAMExists, GAMEndExist, GAMChanged, GAMDeleted
monitor = GaminFam
except ImportError:
# fall back to _fam
try:
import _fam
monitor = FamFam
except ImportError:
print "Couldn't locate Fam module, exiting"
raise SystemExit, 1
class Core(object):
'''The Core object is the container for all Bcfg2 Server logic, and modules'''
def __init__(self, setup, configfile):
object.__init__(self)
cfile = ConfigParser()
cfile.read([configfile])
self.datastore = cfile.get('server','repository')
try:
self.fam = monitor()
except IOError:
raise CoreInitError, "failed to connect to fam"
self.pubspace = {}
self.generators = []
self.structures = []
self.cron = {}
self.setup = setup
self.plugins = {}
mpath = cfile.get('server','repository')
try:
self.metadata = MetadataStore("%s/etc/metadata.xml" % mpath, self.fam)
except OSError:
raise CoreInitError, "metadata path incorrect"
self.stats = Statistics("%s/etc/statistics.xml" % (mpath))
structures = cfile.get('server', 'structures').split(',')
generators = cfile.get('server', 'generators').split(',')
for plugin in structures + generators:
if not self.plugins.has_key(plugin):
try:
mod = getattr(__import__("Bcfg2.Server.Plugins.%s" %
(plugin)).Server.Plugins, plugin)
except ImportError:
syslog(LOG_ERR, "Failed to load plugin %s" % (plugin))
continue
struct = getattr(mod, plugin)
try:
self.plugins[plugin] = struct(self, self.datastore)
except PluginInitError:
syslog(LOG_ERR, "Failed to instantiate plugin %s" % (plugin))
except:
syslog(LOG_ERR, "Unexpected initiantiation failure for plugin %s" % (plugin))
(trace, val, trb)=exc_info()
for line in extract_tb(trb):
syslog(LOG_ERR, ' File "%s", line %i, in %s\n %s\n'%line)
syslog(LOG_ERR, "%s: %s\n"%(trace, val))
del trace, val, trb
for plugin in structures:
if self.plugins.has_key(plugin):
self.structures.append(self.plugins[plugin])
else:
syslog(LOG_ERR, "Plugin %s not loaded. Not enabled as a Structure" % (plugin))
for plugin in generators:
if self.plugins.has_key(plugin):
self.generators.append(self.plugins[plugin])
else:
syslog(LOG_ERR, "Plugin %s not loaded. Not enabled as a Generator" % (plugin))
def GetStructures(self, metadata):
'''Get all structures for client specified by metadata'''
return reduce(lambda x, y:x+y,
[struct.BuildStructures(metadata) for struct in self.structures])
def BindStructure(self, structure, metadata):
'''Bind a complete structure'''
for entry in [child for child in structure.getchildren() if child.tag not in ['SymLink', 'Directory', 'Permissions', 'PostInstall']]:
try:
self.Bind(entry, metadata)
except PluginExecutionError:
syslog(LOG_ERR, "Failed to bind entry: %s %s" % (entry.tag, entry.get('name')))
def Bind(self, entry, metadata):
'''Bind an entry using the appropriate generator'''
glist = [gen for gen in self.generators if
gen.Entries.get(entry.tag, {}).has_key(entry.get('name'))]
if len(glist) == 1:
return glist[0].Entries[entry.tag][entry.get('name')](entry, metadata)
elif len(glist) > 1:
generators = ", ".join([gen.__name__ for gen in glist])
syslog(LOG_ERR, "%s %s served by multiple generators: %s" % (entry.tag,
entry.get('name'), generators))
raise PluginExecutionError, (entry.tag, entry.get('name'))
else:
for gen in self.generators:
if hasattr(gen, "FindHandler"):
return gen.FindHandler(entry)(entry, metadata)
syslog(LOG_ERR, "Failed to find handler for %s:%s" % (entry.tag, entry.get('name')))
raise PluginExecutionError, (entry.tag, entry.get('name'))
def BuildConfiguration(self, client):
'''Build Configuration for client'''
start = time()
config = Element("Configuration", version='2.0')
try:
meta = self.metadata.FetchMetadata(client)
except MetadataConsistencyError:
syslog(LOG_ERR, "Metadata consistency error for client %s" % client)
return Element("error", type='metadata error')
config.set('toolset', meta.toolset)
try:
structures = self.GetStructures(meta)
except:
self.LogFailure("GetStructures")
return Element("error", type='structure error')
for astruct in structures:
try:
self.BindStructure(astruct, meta)
config.append(astruct)
except:
self.LogFailure("BindStructure")
syslog(LOG_INFO, "Generated config for %s in %s seconds"%(client, time() - start))
return config
def LogFailure(self, failure):
'''Log Failures in unexpected cases'''
(trace, val, trb) = exc_info()
syslog(LOG_ERR, "Unexpected failure in %s" % (failure))
for line in extract_tb(trb):
syslog(LOG_ERR, ' File "%s", line %i, in %s\n %s\n' % line)
syslog(LOG_ERR, "%s: %s\n"%(trace, val))
del trace, val, trb
def Service(self):
'''Perform periodic update tasks'''
while self.fam.fm.pending:
try:
self.fam.HandleEvent()
except:
self.LogFailure("FamEvent")
try:
self.stats.WriteBack()
except:
self.LogFailure("Statistics")
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