def __init__(self, cluster):
"""
Initializes the client
"""
self._cluster = ArakoonManagementEx().getCluster(cluster)
self._client = self._cluster.getClient()
self._identifier = int(round(random.random() * 10000000))
self._lock = Lock()
self._batch_size = 100
def __init__(self, cluster):
"""
Initializes the client
"""
self._cluster = ArakoonManagementEx().getCluster(cluster)
self._client = self._cluster.getClient()
self._identifier = int(round(random.random() * 10000000))
self._lock = Lock()
self._batch_size = 100
class ArakoonStore(object):
"""
Arakoon client wrapper:
* Uses json serialisation
* Raises generic exception
"""
def __init__(self, cluster):
"""
Initializes the client
"""
self._cluster = ArakoonManagementEx().getCluster(cluster)
self._client = self._cluster.getClient()
self._identifier = int(round(random.random() * 10000000))
self._lock = Lock()
self._batch_size = 100
@locked()
def get(self, key):
"""
Retrieves a certain value for a given key
"""
try:
return json.loads(
ArakoonStore._try(self._identifier, self._client.get, key))
except ValueError:
raise KeyNotFoundException(
'Could not parse JSON stored for {0}'.format(key))
except ArakoonNotFound as field:
raise KeyNotFoundException(field)
@locked()
def set(self, key, value):
"""
Sets the value for a key to a given value
"""
return ArakoonStore._try(self._identifier, self._client.set, key,
json.dumps(value))
@locked()
def prefix(self, prefix):
"""
Lists all keys starting with the given prefix
"""
next_prefix = ArakoonStore._next_key(prefix)
batch = None
while batch is None or len(batch) > 0:
batch = ArakoonStore._try(
self._identifier,
self._client.range,
beginKey=prefix if batch is None else batch[-1],
beginKeyIncluded=batch is None,
endKey=next_prefix,
endKeyIncluded=False,
maxElements=self._batch_size)
for item in batch:
yield item
@locked()
def delete(self, key):
"""
Deletes a given key from the store
"""
try:
return ArakoonStore._try(self._identifier, self._client.delete,
key)
except ArakoonNotFound as field:
raise KeyNotFoundException(field)
@locked()
def nop(self):
"""
Executes a nop command
"""
return ArakoonStore._try(self._identifier, self._client.nop)
@locked()
def exists(self, key):
"""
Check if key exists
"""
return ArakoonStore._try(self._identifier, self._client.exists, key)
@staticmethod
def _try(identifier, method, *args, **kwargs):
"""
Tries to call a given method, retry-ing if Arakoon is temporary unavailable
"""
try:
last_exception = None
tries = 5
while tries > 0:
try:
start = time.time()
return_value = method(*args, **kwargs)
duration = time.time() - start
if duration > 0.5:
logger.warning('Arakoon call {0} took {1}s'.format(
method.__name__, round(duration, 2)))
return return_value
except ArakoonSockReadNoBytes as exception:
logger.debug('Error during {0}, retry'.format(
method.__name__))
last_exception = exception
tries -= 1
time.sleep(1)
raise last_exception
except ArakoonNotFound:
# No extra logging for ArakoonNotFound
raise
except Exception:
logger.error(
'Error during {0}. Process {1}, thread {2}, clientid {3}'.
format(method.__name__, os.getpid(),
current_thread().ident, identifier))
raise
@staticmethod
def _next_key(key):
"""
Calculates the next key (to be used in range queries)
"""
encoding = 'ascii' # For future python 3 compatibility
array = bytearray(str(key), encoding)
for index in range(len(array) - 1, -1, -1):
array[index] += 1
if array[index] < 128:
while array[-1] == 0:
array = array[:-1]
return str(array.decode(encoding))
array[index] = 0
return '\xff'
class ArakoonStore(object):
"""
Arakoon client wrapper:
* Uses json serialisation
* Raises generic exception
"""
def __init__(self, cluster):
"""
Initializes the client
"""
self._cluster = ArakoonManagementEx().getCluster(cluster)
self._client = self._cluster.getClient()
self._identifier = int(round(random.random() * 10000000))
self._lock = Lock()
self._batch_size = 100
@locked()
def get(self, key):
"""
Retrieves a certain value for a given key
"""
try:
return json.loads(ArakoonStore._try(self._identifier, self._client.get, key))
except ValueError:
raise KeyNotFoundException('Could not parse JSON stored for {0}'.format(key))
except ArakoonNotFound as field:
raise KeyNotFoundException(field)
@locked()
def set(self, key, value):
"""
Sets the value for a key to a given value
"""
return ArakoonStore._try(self._identifier, self._client.set, key, json.dumps(value))
@locked()
def prefix(self, prefix):
"""
Lists all keys starting with the given prefix
"""
next_prefix = ArakoonStore._next_key(prefix)
batch = None
while batch is None or len(batch) > 0:
batch = ArakoonStore._try(self._identifier,
self._client.range,
beginKey=prefix if batch is None else batch[-1],
beginKeyIncluded=batch is None,
endKey=next_prefix,
endKeyIncluded=False,
maxElements=self._batch_size)
for item in batch:
yield item
@locked()
def delete(self, key):
"""
Deletes a given key from the store
"""
try:
return ArakoonStore._try(self._identifier, self._client.delete, key)
except ArakoonNotFound as field:
raise KeyNotFoundException(field)
@locked()
def nop(self):
"""
Executes a nop command
"""
return ArakoonStore._try(self._identifier, self._client.nop)
@locked()
def exists(self, key):
"""
Check if key exists
"""
return ArakoonStore._try(self._identifier, self._client.exists, key)
@staticmethod
def _try(identifier, method, *args, **kwargs):
"""
Tries to call a given method, retry-ing if Arakoon is temporary unavailable
"""
try:
last_exception = None
tries = 5
while tries > 0:
try:
start = time.time()
return_value = method(*args, **kwargs)
duration = time.time() - start
if duration > 0.5:
logger.warning('Arakoon call {0} took {1}s'.format(method.__name__, round(duration, 2)))
return return_value
except ArakoonSockReadNoBytes as exception:
logger.debug('Error during {0}, retry'.format(method.__name__))
last_exception = exception
tries -= 1
time.sleep(1)
raise last_exception
except ArakoonNotFound:
# No extra logging for ArakoonNotFound
raise
except Exception:
logger.error('Error during {0}. Process {1}, thread {2}, clientid {3}'.format(
method.__name__, os.getpid(), current_thread().ident, identifier
))
raise
@staticmethod
def _next_key(key):
"""
Calculates the next key (to be used in range queries)
"""
encoding = 'ascii' # For future python 3 compatibility
array = bytearray(str(key), encoding)
for index in range(len(array) - 1, -1, -1):
array[index] += 1
if array[index] < 128:
while array[-1] == 0:
array = array[:-1]
return str(array.decode(encoding))
array[index] = 0
return '\xff'
