class MemcacheHashCli(object):
def __init__(self, hosts):
self.client = HashClient(hosts)
def set(self, key, value, expire):
try:
return self.client.set(key, value, expire)
except Exception as e:
return False
def get(self, key):
try:
return self.client.get(key, default=None)
except Exception as e:
return None
def mset(self, values, expire):
try:
return self.client.set_many(values, expire)
except Exception as e:
return False
def mget(self, keys):
try:
return self.client.get_many(keys)
except Exception as e:
return None
def test_no_servers_left_with_get_many(self):
from pymemcache.client.hash import HashClient
client = HashClient(
[], use_pooling=True,
ignore_exc=True,
timeout=1, connect_timeout=1
)
result = client.get_many(['foo', 'bar'])
assert result == {'foo': False, 'bar': False}
class MemcacheService(apiproxy_stub.APIProxyStub):
"""Python only memcache service.
This service keeps all data in any external servers running memcached.
"""
# The memcached default port.
MEMCACHE_PORT = 11211
# An AppScale file which has a list of IPs running memcached.
APPSCALE_MEMCACHE_FILE = "/etc/appscale/memcache_ips"
def __init__(self, project_id, service_name='memcache'):
"""Initializer.
Args:
service_name: Service name expected for all calls.
"""
super(MemcacheService, self).__init__(service_name)
self._memcache = None
self.setupMemcacheClient()
self._methods = {
MemcacheSetRequest.SET: self._memcache.set,
MemcacheSetRequest.ADD: self._memcache.add,
MemcacheSetRequest.REPLACE: self._memcache.replace,
MemcacheSetRequest.CAS: self._memcache.cas
}
self._project_id = project_id
def setupMemcacheClient(self):
""" Sets up the memcache client. """
if os.path.exists(self.APPSCALE_MEMCACHE_FILE):
memcache_file = open(self.APPSCALE_MEMCACHE_FILE, "r")
all_ips = memcache_file.read().split("\n")
memcache_file.close()
else:
all_ips = ['localhost']
memcaches = [(ip, self.MEMCACHE_PORT) for ip in all_ips if ip]
memcaches.sort()
self._memcache = HashClient(memcaches,
serializer=serializer,
deserializer=deserializer,
connect_timeout=5,
timeout=1,
use_pooling=True)
# The GAE API expects return values for all mutate operations.
for client in six.itervalues(self._memcache.clients):
client.default_noreply = False
def _Dynamic_Get(self, request, response):
"""Implementation of gets for memcache.
Args:
request: A MemcacheGetRequest protocol buffer.
response: A MemcacheGetResponse protocol buffer.
"""
# Remove duplicate keys.
original_keys = {
encode_key(self._project_id, request.name_space(), key): key
for key in request.key_list()
}
try:
backend_response = self._memcache.get_many(original_keys.keys(),
gets=request.for_cas())
except MemcacheClientError as error:
raise apiproxy_errors.ApplicationError(INVALID_VALUE, str(error))
except TRANSIENT_ERRORS as error:
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR,
'Transient memcache error: {}'.format(error))
for encoded_key, value_tuple in six.iteritems(backend_response):
item = response.add_item()
item.set_key(original_keys[encoded_key])
if request.for_cas():
item.set_cas_id(int(value_tuple[1]))
value_tuple = value_tuple[0]
item.set_value(value_tuple[0])
item.set_flags(value_tuple[1])
def _Dynamic_Set(self, request, response):
"""Implementation of sets for memcache.
Args:
request: A MemcacheSetRequest.
response: A MemcacheSetResponse.
"""
namespace = request.name_space()
if any(item.set_policy() not in self._methods
for item in request.item_list()):
raise apiproxy_errors.ApplicationError(INVALID_VALUE,
'Unsupported set_policy')
if not all(item.has_cas_id() for item in request.item_list()
if item.set_policy() == MemcacheSetRequest.CAS):
raise apiproxy_errors.ApplicationError(
INVALID_VALUE, 'All CAS items must have a cas_id')
for item in request.item_list():
try:
encoded_key = encode_key(self._project_id, namespace,
item.key())
except apiproxy_errors.ApplicationError:
response.add_set_status(MemcacheSetResponse.ERROR)
continue
args = {
'key': encoded_key,
'value': (item.value(), item.flags()),
'expire': int(item.expiration_time())
}
is_cas = item.set_policy() == MemcacheSetRequest.CAS
if is_cas:
args['cas'] = six.binary_type(item.cas_id())
try:
backend_response = self._methods[item.set_policy()](**args)
except (TRANSIENT_ERRORS + (MemcacheClientError, )):
response.add_set_status(MemcacheSetResponse.ERROR)
continue
if backend_response:
response.add_set_status(MemcacheSetResponse.STORED)
continue
if is_cas and backend_response is False:
response.add_set_status(MemcacheSetResponse.EXISTS)
continue
response.add_set_status(MemcacheSetResponse.NOT_STORED)
def _Dynamic_Delete(self, request, response):
"""Implementation of delete in memcache.
Args:
request: A MemcacheDeleteRequest protocol buffer.
response: A MemcacheDeleteResponse protocol buffer.
"""
for item in request.item_list():
encoded_key = encode_key(self._project_id, request.name_space(),
item.key())
try:
key_existed = self._memcache.delete(encoded_key)
except MemcacheClientError as error:
raise apiproxy_errors.ApplicationError(INVALID_VALUE,
str(error))
except TRANSIENT_ERRORS as error:
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR,
'Transient memcache error: {}'.format(error))
response.add_delete_status(
MemcacheDeleteResponse.
DELETED if key_existed else MemcacheDeleteResponse.NOT_FOUND)
def _Increment(self, namespace, request):
"""Internal function for incrementing from a MemcacheIncrementRequest.
Args:
namespace: A string containing the namespace for the request,
if any. Pass an empty string if there is no namespace.
request: A MemcacheIncrementRequest instance.
Returns:
An integer indicating the new value.
Raises:
ApplicationError if unable to perform the mutation.
"""
encoded_key = encode_key(self._project_id, namespace, request.key())
method = self._memcache.incr
if request.direction() == MemcacheIncrementRequest.DECREMENT:
method = self._memcache.decr
try:
response = method(encoded_key, request.delta())
except MemcacheClientError as error:
raise apiproxy_errors.ApplicationError(INVALID_VALUE, str(error))
except TRANSIENT_ERRORS as error:
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR,
'Transient memcache error: {}'.format(error))
if response is None and not request.has_initial_value():
raise apiproxy_errors.ApplicationError(UNSPECIFIED_ERROR,
'Key does not exist')
if response is not None:
return response
# If the key was not present and an initial value was provided, perform
# the mutation client-side and set the key if it still doesn't exist.
flags = 0
if request.has_initial_flags():
flags = request.initial_flags()
if request.direction() == MemcacheIncrementRequest.INCREMENT:
updated_val = request.initial_value() + request.delta()
else:
updated_val = request.initial_value() - request.delta()
updated_val = max(updated_val, 0) % (MAX_INCR + 1)
try:
response = self._memcache.add(
encoded_key, (six.binary_type(updated_val), flags))
except (TRANSIENT_ERRORS + (MemcacheClientError, )):
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR, 'Unable to set initial value')
if response is False:
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR, 'Unable to set initial value')
return updated_val
def _Dynamic_Increment(self, request, response):
"""Implementation of increment for memcache.
Args:
request: A MemcacheIncrementRequest protocol buffer.
response: A MemcacheIncrementResponse protocol buffer.
"""
new_value = self._Increment(request.name_space(), request)
response.set_new_value(new_value)
def _Dynamic_BatchIncrement(self, request, response):
"""Implementation of batch increment for memcache.
Args:
request: A MemcacheBatchIncrementRequest protocol buffer.
response: A MemcacheBatchIncrementResponse protocol buffer.
"""
for request_item in request.item_list():
item = response.add_item()
try:
new_value = self._Increment(request.name_space(), request_item)
except apiproxy_errors.ApplicationError as error:
if error.application_error == INVALID_VALUE:
item.set_increment_status(
MemcacheIncrementResponse.NOT_CHANGED)
else:
item.set_increment_status(MemcacheIncrementResponse.ERROR)
continue
item.set_increment_status(MemcacheIncrementResponse.OK)
item.set_new_value(new_value)
def _Dynamic_FlushAll(self, request, response):
"""Implementation of MemcacheService::FlushAll().
Args:
request: A MemcacheFlushRequest.
response: A MemcacheFlushResponse.
"""
# TODO: Prevent a project from clearing another project's namespace.
self._memcache.flush_all()
def _Dynamic_Stats(self, request, response):
"""Implementation of MemcacheService::Stats().
Args:
request: A MemcacheStatsRequest.
response: A MemcacheStatsResponse.
"""
# TODO: Gather stats for a project rather than the deployment.
hits = 0
misses = 0
byte_hits = 0
items = 0
byte_count = 0
oldest_item_age = 0
for server in six.itervalues(self._memcache.clients):
server_stats = server.stats()
hits += server_stats.get('get_hits', 0)
misses += server_stats.get('get_misses', 0)
byte_hits += server_stats.get('bytes_read', 0)
items += server_stats.get('curr_items', 0)
byte_count += server_stats.get('bytes', 0)
# Using the "age" field may not be correct here. The GAE docs claim this
# should specify "how long in seconds since the oldest item in the cache
# was accessed" rather than when it was created.
item_stats = server.stats('items')
oldest_server_item = max(age
for key, age in six.iteritems(item_stats)
if key.endswith(':age'))
oldest_item_age = max(oldest_item_age, oldest_server_item)
stats = response.mutable_stats()
stats.set_hits(hits)
stats.set_misses(misses)
stats.set_byte_hits(byte_hits)
stats.set_items(items)
stats.set_bytes(byte_count)
stats.set_oldest_item_age(oldest_item_age)
class MemcacheService(apiproxy_stub.APIProxyStub):
"""Python only memcache service.
This service keeps all data in any external servers running memcached.
"""
# The memcached default port.
MEMCACHE_PORT = 11211
# An AppScale file which has a list of IPs running memcached.
APPSCALE_MEMCACHE_FILE = "/etc/appscale/memcache_ips"
def __init__(self, project_id, service_name='memcache'):
"""Initializer.
Args:
service_name: Service name expected for all calls.
"""
super(MemcacheService, self).__init__(service_name)
self._memcache = None
self.setupMemcacheClient()
self._methods = {MemcacheSetRequest.SET: self._memcache.set,
MemcacheSetRequest.ADD: self._memcache.add,
MemcacheSetRequest.REPLACE: self._memcache.replace,
MemcacheSetRequest.CAS: self._memcache.cas}
self._project_id = project_id
def setupMemcacheClient(self):
""" Sets up the memcache client. """
if os.path.exists(self.APPSCALE_MEMCACHE_FILE):
memcache_file = open(self.APPSCALE_MEMCACHE_FILE, "r")
all_ips = memcache_file.read().split("\n")
memcache_file.close()
else:
all_ips = ['localhost']
memcaches = [(ip, self.MEMCACHE_PORT) for ip in all_ips if ip]
memcaches.sort()
self._memcache = HashClient(
memcaches, serializer=serializer, deserializer=deserializer,
connect_timeout=5, timeout=1, use_pooling=True)
# The GAE API expects return values for all mutate operations.
for client in six.itervalues(self._memcache.clients):
client.default_noreply = False
def _Dynamic_Get(self, request, response):
"""Implementation of gets for memcache.
Args:
request: A MemcacheGetRequest protocol buffer.
response: A MemcacheGetResponse protocol buffer.
"""
# Remove duplicate keys.
original_keys = {
encode_key(self._project_id, request.name_space(), key): key
for key in request.key_list()}
try:
backend_response = self._memcache.get_many(
original_keys.keys(), gets=request.for_cas())
except MemcacheClientError as error:
raise apiproxy_errors.ApplicationError(INVALID_VALUE, str(error))
except TRANSIENT_ERRORS as error:
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR, 'Transient memcache error: {}'.format(error))
for encoded_key, value_tuple in six.iteritems(backend_response):
item = response.add_item()
item.set_key(original_keys[encoded_key])
if request.for_cas():
item.set_cas_id(int(value_tuple[1]))
value_tuple = value_tuple[0]
item.set_value(value_tuple[0])
item.set_flags(value_tuple[1])
def _Dynamic_Set(self, request, response):
"""Implementation of sets for memcache.
Args:
request: A MemcacheSetRequest.
response: A MemcacheSetResponse.
"""
namespace = request.name_space()
if any(item.set_policy() not in self._methods
for item in request.item_list()):
raise apiproxy_errors.ApplicationError(
INVALID_VALUE, 'Unsupported set_policy')
if not all(item.has_cas_id() for item in request.item_list()
if item.set_policy() == MemcacheSetRequest.CAS):
raise apiproxy_errors.ApplicationError(
INVALID_VALUE, 'All CAS items must have a cas_id')
for item in request.item_list():
try:
encoded_key = encode_key(self._project_id, namespace, item.key())
except apiproxy_errors.ApplicationError:
response.add_set_status(MemcacheSetResponse.ERROR)
continue
args = {'key': encoded_key,
'value': (item.value(), item.flags()),
'expire': int(item.expiration_time())}
is_cas = item.set_policy() == MemcacheSetRequest.CAS
if is_cas:
args['cas'] = six.binary_type(item.cas_id())
try:
backend_response = self._methods[item.set_policy()](**args)
except (TRANSIENT_ERRORS + (MemcacheClientError,)):
response.add_set_status(MemcacheSetResponse.ERROR)
continue
if backend_response:
response.add_set_status(MemcacheSetResponse.STORED)
continue
if is_cas and backend_response is False:
response.add_set_status(MemcacheSetResponse.EXISTS)
continue
response.add_set_status(MemcacheSetResponse.NOT_STORED)
def _Dynamic_Delete(self, request, response):
"""Implementation of delete in memcache.
Args:
request: A MemcacheDeleteRequest protocol buffer.
response: A MemcacheDeleteResponse protocol buffer.
"""
for item in request.item_list():
encoded_key = encode_key(self._project_id, request.name_space(),
item.key())
try:
key_existed = self._memcache.delete(encoded_key)
except MemcacheClientError as error:
raise apiproxy_errors.ApplicationError(INVALID_VALUE, str(error))
except TRANSIENT_ERRORS as error:
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR, 'Transient memcache error: {}'.format(error))
response.add_delete_status(MemcacheDeleteResponse.DELETED if key_existed
else MemcacheDeleteResponse.NOT_FOUND)
def _Increment(self, namespace, request):
"""Internal function for incrementing from a MemcacheIncrementRequest.
Args:
namespace: A string containing the namespace for the request,
if any. Pass an empty string if there is no namespace.
request: A MemcacheIncrementRequest instance.
Returns:
An integer indicating the new value.
Raises:
ApplicationError if unable to perform the mutation.
"""
encoded_key = encode_key(self._project_id, namespace, request.key())
method = self._memcache.incr
if request.direction() == MemcacheIncrementRequest.DECREMENT:
method = self._memcache.decr
try:
response = method(encoded_key, request.delta())
except MemcacheClientError as error:
raise apiproxy_errors.ApplicationError(INVALID_VALUE, str(error))
except TRANSIENT_ERRORS as error:
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR, 'Transient memcache error: {}'.format(error))
if response is None and not request.has_initial_value():
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR, 'Key does not exist')
if response is not None:
return response
# If the key was not present and an initial value was provided, perform
# the mutation client-side and set the key if it still doesn't exist.
flags = 0
if request.has_initial_flags():
flags = request.initial_flags()
if request.direction() == MemcacheIncrementRequest.INCREMENT:
updated_val = request.initial_value() + request.delta()
else:
updated_val = request.initial_value() - request.delta()
updated_val = max(updated_val, 0) % (MAX_INCR + 1)
try:
response = self._memcache.add(
encoded_key, (six.binary_type(updated_val), flags))
except (TRANSIENT_ERRORS + (MemcacheClientError,)):
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR, 'Unable to set initial value')
if response is False:
raise apiproxy_errors.ApplicationError(
UNSPECIFIED_ERROR, 'Unable to set initial value')
return updated_val
def _Dynamic_Increment(self, request, response):
"""Implementation of increment for memcache.
Args:
request: A MemcacheIncrementRequest protocol buffer.
response: A MemcacheIncrementResponse protocol buffer.
"""
new_value = self._Increment(request.name_space(), request)
response.set_new_value(new_value)
def _Dynamic_BatchIncrement(self, request, response):
"""Implementation of batch increment for memcache.
Args:
request: A MemcacheBatchIncrementRequest protocol buffer.
response: A MemcacheBatchIncrementResponse protocol buffer.
"""
for request_item in request.item_list():
item = response.add_item()
try:
new_value = self._Increment(request.name_space(), request_item)
except apiproxy_errors.ApplicationError as error:
if error.application_error == INVALID_VALUE:
item.set_increment_status(MemcacheIncrementResponse.NOT_CHANGED)
else:
item.set_increment_status(MemcacheIncrementResponse.ERROR)
continue
item.set_increment_status(MemcacheIncrementResponse.OK)
item.set_new_value(new_value)
def _Dynamic_FlushAll(self, request, response):
"""Implementation of MemcacheService::FlushAll().
Args:
request: A MemcacheFlushRequest.
response: A MemcacheFlushResponse.
"""
# TODO: Prevent a project from clearing another project's namespace.
self._memcache.flush_all()
def _Dynamic_Stats(self, request, response):
"""Implementation of MemcacheService::Stats().
Args:
request: A MemcacheStatsRequest.
response: A MemcacheStatsResponse.
"""
# TODO: Gather stats for a project rather than the deployment.
hits = 0
misses = 0
byte_hits = 0
items = 0
byte_count = 0
oldest_item_age = 0
for server in six.itervalues(self._memcache.clients):
server_stats = server.stats()
hits += server_stats.get('get_hits', 0)
misses += server_stats.get('get_misses', 0)
byte_hits += server_stats.get('bytes_read', 0)
items += server_stats.get('curr_items', 0)
byte_count += server_stats.get('bytes', 0)
# Using the "age" field may not be correct here. The GAE docs claim this
# should specify "how long in seconds since the oldest item in the cache
# was accessed" rather than when it was created.
item_stats = server.stats('items')
oldest_server_item = max(age for key, age in six.iteritems(item_stats)
if key.endswith(':age'))
oldest_item_age = max(oldest_item_age, oldest_server_item)
stats = response.mutable_stats()
stats.set_hits(hits)
stats.set_misses(misses)
stats.set_byte_hits(byte_hits)
stats.set_items(items)
stats.set_bytes(byte_count)
stats.set_oldest_item_age(oldest_item_age)
class CouchbaseMemcacheMirror(object):
def __init__(self, couchbase_uri, memcached_hosts, primary=PRIMARY_COUCHBASE):
"""
:param couchbase_uri: Connection string for Couchbase
:param memcached_hosts: List of Memcached nodes
:param primary: Determines which datastore is authoritative.
This affects how get operations are performed and which datastore
is used for CAS operations.
PRIMARY_COUCHBASE: Couchbase is authoritative
PRIMARY_MEMCACHED: Memcached is authoritative
By default, Couchbase is the primary store
:return:
"""
self.cb = CbBucket(couchbase_uri)
self.mc = McClient(memcached_hosts)
self._primary = primary
@property
def primary(self):
return self._primary
def _cb_get(self, key):
try:
return self.cb.get(key).value
except NotFoundError:
return None
def get(self, key, try_alternate=True):
"""
Gets a document
:param key: The key to retrieve
:param try_alternate: Whether to try the secondary data source if the
item is not found in the primary.
:return: The value as a Python object
"""
if self._primary == PRIMARY_COUCHBASE:
order = [self._cb_get, self.mc.get]
else:
order = [self.mc.get, self._cb_get]
for meth in order:
ret = meth(key)
if ret or not try_alternate:
return ret
return None
def _cb_mget(self, keys):
"""
Internal method to execute a Couchbase multi-get
:param keys: The keys to retrieve
:return: A tuple of {found_key:found_value, ...}, [missing_key1,...]
"""
try:
ok_rvs = self.cb.get_multi(keys)
bad_rvs = {}
except NotFoundError as e:
ok_rvs, bad_rvs = e.split_results()
ok_dict = {k: (v.value, v.cas) for k, v in ok_rvs}
return ok_dict, bad_rvs.keys()
def get_multi(self, keys, try_alternate=True):
"""
Gets multiple items from the server
:param keys: The keys to fetch as an iterable
:param try_alternate: Whether to fetch missing items from alternate store
:return: A dictionary of key:value. Only contains keys which exist and have values
"""
if self._primary == PRIMARY_COUCHBASE:
ok, err = self._cb_get(keys)
if err and try_alternate:
ok.update(self.mc.get_many(err))
return ok
else:
ok = self.mc.get_many(keys)
if len(ok) < len(keys) and try_alternate:
keys_err = set(keys) - set(ok)
ok.update(self._cb_mget(list(keys_err))[0])
return ok
def gets(self, key):
"""
Get an item with its CAS. The item will always be fetched from the primary
data store.
:param key: the key to get
:return: the value of the key, or None if no such value
"""
if self._primary == PRIMARY_COUCHBASE:
try:
rv = self.cb.get(key)
return key, rv.cas
except NotFoundError:
return None, None
else:
return self.mc.gets(key)
def gets_multi(self, keys):
if self._primary == PRIMARY_COUCHBASE:
try:
rvs = self.cb.get_multi(keys)
except NotFoundError as e:
rvs, _ = e.split_results()
return {k: (v.value, v.cas) for k, v in rvs}
else:
# TODO: I'm not sure if this is implemented in HasClient :(
return self.mc.gets_many(keys)
def delete(self, key):
st = Status()
try:
self.cb.remove(key)
except NotFoundError as e:
st.cb_error = e
st.mc_status = self.mc.delete(key)
return st
def delete_multi(self, keys):
st = Status()
try:
self.cb.remove_multi(keys)
except NotFoundError as e:
st.cb_error = e
st.mc_status = self.mc.delete_many(keys)
def _do_incrdecr(self, key, value, is_incr):
cb_value = value if is_incr else -value
mc_meth = self.mc.incr if is_incr else self.mc.decr
st = Status()
try:
self.cb.counter(key, delta=cb_value)
except NotFoundError as e:
st.cb_error = e
st.mc_status = mc_meth(key, value)
def incr(self, key, value):
return self._do_incrdecr(key, value, True)
def decr(self, key, value):
return self._do_incrdecr(key, value, False)
def touch(self, key, expire=0):
st = Status()
try:
self.cb.touch(key, ttl=expire)
except NotFoundError as e:
st.cb_error = st
st.mc_status = self.mc.touch(key)
def set(self, key, value, expire=0):
"""
Write first to Couchbase, and then to Memcached
:param key: Key to use
:param value: Value to use
:param expire: If set, the item will expire in the given amount of time
:return: Status object if successful (will always be success).
on failure an exception is raised
"""
self.cb.upsert(key, value, ttl=expire)
self.mc.set(key, value, expire=expire)
return Status()
def set_multi(self, values, expire=0):
"""
Set multiple items.
:param values: A dictionary of key, value indicating values to store
:param expire: If present, expiration time for all the items
:return:
"""
self.cb.upsert_multi(values, ttl=expire)
self.mc.set_many(values, expire=expire)
return Status()
def replace(self, key, value, expire=0):
"""
Replace existing items
:param key: key to replace
:param value: new value
:param expire: expiration for item
:return: Status object. Will be OK
"""
status = Status()
try:
self.cb.replace(key, value, ttl=expire)
except NotFoundError as e:
status.cb_error = e
status.mc_status = self.mc.replace(key, value, expire=expire)
return status
def add(self, key, value, expire=0):
status = Status()
try:
self.cb.insert(key, value, ttl=expire)
except KeyExistsError as e:
status.cb_error = e
status.mc_status = self.mc.add(key, value, expire=expire)
return status
def _append_prepend(self, key, value, is_append):
cb_meth = self.cb.append if is_append else self.cb.prepend
mc_meth = self.mc.append if is_append else self.mc.prepend
st = Status()
try:
cb_meth(key, value, format=FMT_UTF8)
except (NotStoredError, NotFoundError) as e:
st.cb_error = e
st.mc_status = mc_meth(key, value)
def append(self, key, value):
return self._append_prepend(key, value, True)
def prepend(self, key, value):
return self._append_prepend(key, value, False)
def cas(self, key, value, cas, expire=0):
if self._primary == PRIMARY_COUCHBASE:
try:
self.cb.replace(key, value, cas=cas, ttl=expire)
self.mc.set(key, value, ttl=expire)
return True
except KeyExistsError:
return False
except NotFoundError:
return None
else:
return self.mc.cas(key, value, cas)
