#
# Copyright (c) 2014, Arista Networks, Inc.
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# Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
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# notice, this list of conditions and the following disclaimer in the
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# this software without specific prior written permission.
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import os
import logging
import ztpserver.config
from ztpserver.serializers import load, dump
from ztpserver.constants import CONTENT_TYPE_YAML
log = logging.getLogger(__name__) #pylint: disable=C0103
[docs]class ResourcePoolError(Exception):
''' base error raised by :py:class:`Resource` '''
pass
[docs]class ResourcePool(object):
def __init__(self, node_id):
self.node_id = node_id
cfg = ztpserver.config.runtime
self.file_path = os.path.join(cfg.default.data_root, 'resources')
self.data = None
[docs] def serialize(self):
data = dict()
for key, value in self.data.items():
data[key] = str(value) if value is not None else None
return data
[docs] def load(self, pool):
self.data = dict()
filename = os.path.join(self.file_path, pool)
contents = load(filename, CONTENT_TYPE_YAML, self.node_id)
for key, value in contents.items():
self.data[key] = str(value) if value is not None else None
[docs] def dump(self, pool):
file_path = os.path.join(self.file_path, pool)
dump(self, file_path, CONTENT_TYPE_YAML, self.node_id)
[docs] def allocate(self, pool, node):
node_id = node.identifier()
log.debug('%s: allocating resources' % node_id)
match = self.lookup(pool, node)
try:
if match:
log.debug('%s: already allocated resource \'%s\':\'%s\'' %
(node_id, pool, match))
return match
self.load(pool)
key = next(x[0] for x in self.data.items() if x[1] is None)
log.debug('%s: allocated \'%s\':\'%s\'' %
(node_id, pool, key))
self.data[key] = node_id
self.dump(pool)
except StopIteration:
log.error('%s: no resource free in \'%s\'' % (node_id, pool))
raise ResourcePoolError('%s: no resource free in \'%s\'' %
(node_id, pool))
except Exception as exc:
log.error('%s: failed to allocate resource from \'%s\'' %
(node_id, pool))
raise ResourcePoolError(exc.message)
return str(key)
[docs] def lookup(self, pool, node):
''' Return an existing allocated resource if one exists '''
node_id = node.identifier()
log.debug('%s: looking up resource in \'%s\'' %
(node_id, pool))
try:
self.load(pool)
matches = [m[0] for m in self.data.iteritems()
if m[1] == node_id]
key = matches[0] if matches else None
return key
except Exception as exc:
log.error('%s: failed to lookup resource from \'%s\'' %
(node_id, pool))
raise ResourcePoolError(exc.message)