119 lines
3.5 KiB
Python
119 lines
3.5 KiB
Python
from datetime import datetime
|
|
from uuid import uuid1
|
|
|
|
from cqlengine.exceptions import ValidationError
|
|
|
|
class QueryValue(object):
|
|
"""
|
|
Base class for query filter values. Subclasses of these classes can
|
|
be passed into .filter() keyword args
|
|
"""
|
|
|
|
format_string = ':{}'
|
|
|
|
def __init__(self, value):
|
|
self.value = value
|
|
self.context_id = None
|
|
|
|
def __unicode__(self):
|
|
return self.format_string.format(self.context_id)
|
|
|
|
def set_context_id(self, ctx_id):
|
|
self.context_id = ctx_id
|
|
|
|
def get_context_size(self):
|
|
return 1
|
|
|
|
def update_context(self, ctx):
|
|
ctx[str(self.context_id)] = self.value
|
|
|
|
|
|
class BaseQueryFunction(QueryValue):
|
|
"""
|
|
Base class for filtering functions. Subclasses of these classes can
|
|
be passed into .filter() and will be translated into CQL functions in
|
|
the resulting query
|
|
"""
|
|
|
|
class MinTimeUUID(BaseQueryFunction):
|
|
"""
|
|
return a fake timeuuid corresponding to the smallest possible timeuuid for the given timestamp
|
|
|
|
http://cassandra.apache.org/doc/cql3/CQL.html#timeuuidFun
|
|
"""
|
|
|
|
format_string = 'MinTimeUUID(:{})'
|
|
|
|
def __init__(self, value):
|
|
"""
|
|
:param value: the time to create a maximum time uuid from
|
|
:type value: datetime
|
|
"""
|
|
if not isinstance(value, datetime):
|
|
raise ValidationError('datetime instance is required')
|
|
super(MinTimeUUID, self).__init__(value)
|
|
|
|
def to_database(self, val):
|
|
epoch = datetime(1970, 1, 1, tzinfo=val.tzinfo)
|
|
offset = epoch.tzinfo.utcoffset(epoch).total_seconds() if epoch.tzinfo else 0
|
|
return long(((val - epoch).total_seconds() - offset) * 1000)
|
|
|
|
def update_context(self, ctx):
|
|
ctx[str(self.context_id)] = self.to_database(self.value)
|
|
|
|
|
|
class MaxTimeUUID(BaseQueryFunction):
|
|
"""
|
|
return a fake timeuuid corresponding to the largest possible timeuuid for the given timestamp
|
|
|
|
http://cassandra.apache.org/doc/cql3/CQL.html#timeuuidFun
|
|
"""
|
|
|
|
format_string = 'MaxTimeUUID(:{})'
|
|
|
|
def __init__(self, value):
|
|
"""
|
|
:param value: the time to create a minimum time uuid from
|
|
:type value: datetime
|
|
"""
|
|
if not isinstance(value, datetime):
|
|
raise ValidationError('datetime instance is required')
|
|
super(MaxTimeUUID, self).__init__(value)
|
|
|
|
def to_database(self, val):
|
|
epoch = datetime(1970, 1, 1, tzinfo=val.tzinfo)
|
|
offset = epoch.tzinfo.utcoffset(epoch).total_seconds() if epoch.tzinfo else 0
|
|
return long(((val - epoch).total_seconds() - offset) * 1000)
|
|
|
|
def update_context(self, ctx):
|
|
ctx[str(self.context_id)] = self.to_database(self.value)
|
|
|
|
|
|
class Token(BaseQueryFunction):
|
|
"""
|
|
compute the token for a given partition key
|
|
|
|
http://cassandra.apache.org/doc/cql3/CQL.html#tokenFun
|
|
"""
|
|
|
|
def __init__(self, *values):
|
|
if len(values) == 1 and isinstance(values[0], (list, tuple)):
|
|
values = values[0]
|
|
super(Token, self).__init__(values)
|
|
self._columns = None
|
|
|
|
def set_columns(self, columns):
|
|
self._columns = columns
|
|
|
|
def get_context_size(self):
|
|
return len(self.value)
|
|
|
|
def __unicode__(self):
|
|
token_args = ', '.join(':{}'.format(self.context_id + i) for i in range(self.get_context_size()))
|
|
return "token({})".format(token_args)
|
|
|
|
def update_context(self, ctx):
|
|
for i, (col, val) in enumerate(zip(self._columns, self.value)):
|
|
ctx[str(self.context_id + i)] = col.to_database(val)
|
|
|