class PolicyEngine(threading.Thread):
"""
At a regular interval, this thread triggers system reconfiguration by
sampling host and guest data, evaluating the policy and reporting the
results to all enabled Controller plugins.
"""
def __init__(self, config, hypervisor_iface, host_monitor, guest_manager):
threading.Thread.__init__(self, name="PolicyEngine")
self.setDaemon(True)
self.config = config
self.logger = logging.getLogger('mom.PolicyEngine')
self.properties = {
'hypervisor_iface': hypervisor_iface,
'host_monitor': host_monitor,
'guest_manager': guest_manager,
}
self.policy = Policy()
self.load_policy()
self.start()
def load_policy(self):
def read_policy(file_name, policy_name):
try:
with open(file_name, 'r') as f:
policyStr = f.read()
except IOError, e:
self.logger.warn("Unable to read policy file: %s" % e)
return False
return self.policy.set_policy(policy_name, policyStr)
fname = self.config.get('main', 'policy')
if fname:
return read_policy(fname, None)
policy_dir = self.config.get('main', 'policy-dir')
if policy_dir:
try:
names = sorted(os.listdir(policy_dir))
except OSError, e:
self.logger.warn("Unable to read directory '%s': %s" % (
policy_dir, e.strerror))
return False
for name in names:
if name.startswith('.') or not name.endswith('.policy'):
continue
fname = os.path.join(policy_dir, name)
read_policy(fname, name.split('.policy')[0])
return True
