Files
deb-python-cassandra-driver/cqlengine/statements.py

818 lines
26 KiB
Python

import time
from datetime import datetime, timedelta
import six
from cqlengine.functions import QueryValue
from cqlengine.operators import BaseWhereOperator, InOperator
class StatementException(Exception): pass
import sys
class UnicodeMixin(object):
if sys.version_info > (3, 0):
__str__ = lambda x: x.__unicode__()
else:
__str__ = lambda x: six.text_type(x).encode('utf-8')
class ValueQuoter(UnicodeMixin):
def __init__(self, value):
self.value = value
def __unicode__(self):
from cassandra.encoder import cql_quote
if isinstance(self.value, bool):
return 'true' if self.value else 'false'
elif isinstance(self.value, (list, tuple)):
return '[' + ', '.join([cql_quote(v) for v in self.value]) + ']'
elif isinstance(self.value, dict):
return '{' + ', '.join([cql_quote(k) + ':' + cql_quote(v) for k,v in self.value.items()]) + '}'
elif isinstance(self.value, set):
return '{' + ', '.join([cql_quote(v) for v in self.value]) + '}'
return cql_quote(self.value)
def __eq__(self, other):
if isinstance(other, self.__class__):
return self.value == other.value
return False
class InQuoter(ValueQuoter):
def __unicode__(self):
from cassandra.encoder import cql_quote
return '(' + ', '.join([cql_quote(v) for v in self.value]) + ')'
class BaseClause(UnicodeMixin):
def __init__(self, field, value):
self.field = field
self.value = value
self.context_id = None
def __unicode__(self):
raise NotImplementedError
def __hash__(self):
return hash(self.field) ^ hash(self.value)
def __eq__(self, other):
if isinstance(other, self.__class__):
return self.field == other.field and self.value == other.value
return False
def __ne__(self, other):
return not self.__eq__(other)
def get_context_size(self):
""" returns the number of entries this clause will add to the query context """
return 1
def set_context_id(self, i):
""" sets the value placeholder that will be used in the query """
self.context_id = i
def update_context(self, ctx):
""" updates the query context with this clauses values """
assert isinstance(ctx, dict)
ctx[str(self.context_id)] = self.value
class WhereClause(BaseClause):
""" a single where statement used in queries """
def __init__(self, field, operator, value, quote_field=True):
"""
:param field:
:param operator:
:param value:
:param quote_field: hack to get the token function rendering properly
:return:
"""
if not isinstance(operator, BaseWhereOperator):
raise StatementException(
"operator must be of type {}, got {}".format(BaseWhereOperator, type(operator))
)
super(WhereClause, self).__init__(field, value)
self.operator = operator
self.query_value = self.value if isinstance(self.value, QueryValue) else QueryValue(self.value)
self.quote_field = quote_field
def __unicode__(self):
field = ('"{}"' if self.quote_field else '{}').format(self.field)
return u'{} {} {}'.format(field, self.operator, six.text_type(self.query_value))
def __hash__(self):
return super(WhereClause, self).__hash__() ^ hash(self.operator)
def __eq__(self, other):
if super(WhereClause, self).__eq__(other):
return self.operator.__class__ == other.operator.__class__
return False
def get_context_size(self):
return self.query_value.get_context_size()
def set_context_id(self, i):
super(WhereClause, self).set_context_id(i)
self.query_value.set_context_id(i)
def update_context(self, ctx):
if isinstance(self.operator, InOperator):
ctx[str(self.context_id)] = InQuoter(self.value)
else:
self.query_value.update_context(ctx)
class AssignmentClause(BaseClause):
""" a single variable st statement """
def __unicode__(self):
return u'"{}" = %({})s'.format(self.field, self.context_id)
def insert_tuple(self):
return self.field, self.context_id
class TransactionClause(BaseClause):
""" A single variable iff statement """
def __unicode__(self):
return u'"{}" = %({})s'.format(self.field, self.context_id)
def insert_tuple(self):
return self.field, self.context_id
class ContainerUpdateClause(AssignmentClause):
def __init__(self, field, value, operation=None, previous=None, column=None):
super(ContainerUpdateClause, self).__init__(field, value)
self.previous = previous
self._assignments = None
self._operation = operation
self._analyzed = False
self._column = column
def _to_database(self, val):
return self._column.to_database(val) if self._column else val
def _analyze(self):
raise NotImplementedError
def get_context_size(self):
raise NotImplementedError
def update_context(self, ctx):
raise NotImplementedError
class SetUpdateClause(ContainerUpdateClause):
""" updates a set collection """
def __init__(self, field, value, operation=None, previous=None, column=None):
super(SetUpdateClause, self).__init__(field, value, operation, previous, column=column)
self._additions = None
self._removals = None
def __unicode__(self):
qs = []
ctx_id = self.context_id
if (self.previous is None and
self._assignments is None and
self._additions is None and
self._removals is None):
qs += ['"{}" = %({})s'.format(self.field, ctx_id)]
if self._assignments is not None:
qs += ['"{}" = %({})s'.format(self.field, ctx_id)]
ctx_id += 1
if self._additions is not None:
qs += ['"{0}" = "{0}" + %({1})s'.format(self.field, ctx_id)]
ctx_id += 1
if self._removals is not None:
qs += ['"{0}" = "{0}" - %({1})s'.format(self.field, ctx_id)]
return ', '.join(qs)
def _analyze(self):
""" works out the updates to be performed """
if self.value is None or self.value == self.previous:
pass
elif self._operation == "add":
self._additions = self.value
elif self._operation == "remove":
self._removals = self.value
elif self.previous is None:
self._assignments = self.value
else:
# partial update time
self._additions = (self.value - self.previous) or None
self._removals = (self.previous - self.value) or None
self._analyzed = True
def get_context_size(self):
if not self._analyzed: self._analyze()
if (self.previous is None and
not self._assignments and
self._additions is None and
self._removals is None):
return 1
return int(bool(self._assignments)) + int(bool(self._additions)) + int(bool(self._removals))
def update_context(self, ctx):
if not self._analyzed: self._analyze()
ctx_id = self.context_id
if (self.previous is None and
self._assignments is None and
self._additions is None and
self._removals is None):
ctx[str(ctx_id)] = self._to_database({})
if self._assignments is not None:
ctx[str(ctx_id)] = self._to_database(self._assignments)
ctx_id += 1
if self._additions is not None:
ctx[str(ctx_id)] = self._to_database(self._additions)
ctx_id += 1
if self._removals is not None:
ctx[str(ctx_id)] = self._to_database(self._removals)
class ListUpdateClause(ContainerUpdateClause):
""" updates a list collection """
def __init__(self, field, value, operation=None, previous=None, column=None):
super(ListUpdateClause, self).__init__(field, value, operation, previous, column=column)
self._append = None
self._prepend = None
def __unicode__(self):
if not self._analyzed: self._analyze()
qs = []
ctx_id = self.context_id
if self._assignments is not None:
qs += ['"{}" = %({})s'.format(self.field, ctx_id)]
ctx_id += 1
if self._prepend is not None:
qs += ['"{0}" = %({1})s + "{0}"'.format(self.field, ctx_id)]
ctx_id += 1
if self._append is not None:
qs += ['"{0}" = "{0}" + %({1})s'.format(self.field, ctx_id)]
return ', '.join(qs)
def get_context_size(self):
if not self._analyzed: self._analyze()
return int(self._assignments is not None) + int(bool(self._append)) + int(bool(self._prepend))
def update_context(self, ctx):
if not self._analyzed: self._analyze()
ctx_id = self.context_id
if self._assignments is not None:
ctx[str(ctx_id)] = self._to_database(self._assignments)
ctx_id += 1
if self._prepend is not None:
# CQL seems to prepend element at a time, starting
# with the element at idx 0, we can either reverse
# it here, or have it inserted in reverse
ctx[str(ctx_id)] = self._to_database(list(reversed(self._prepend)))
ctx_id += 1
if self._append is not None:
ctx[str(ctx_id)] = self._to_database(self._append)
def _analyze(self):
""" works out the updates to be performed """
if self.value is None or self.value == self.previous:
pass
elif self._operation == "append":
self._append = self.value
elif self._operation == "prepend":
# self.value is a Quoter but we reverse self._prepend later as if
# it's a list, so we have to set it to the underlying list
self._prepend = self.value.value
elif self.previous is None:
self._assignments = self.value
elif len(self.value) < len(self.previous):
# if elements have been removed,
# rewrite the whole list
self._assignments = self.value
elif len(self.previous) == 0:
# if we're updating from an empty
# list, do a complete insert
self._assignments = self.value
else:
# the max start idx we want to compare
search_space = len(self.value) - max(0, len(self.previous)-1)
# the size of the sub lists we want to look at
search_size = len(self.previous)
for i in range(search_space):
#slice boundary
j = i + search_size
sub = self.value[i:j]
idx_cmp = lambda idx: self.previous[idx] == sub[idx]
if idx_cmp(0) and idx_cmp(-1) and self.previous == sub:
self._prepend = self.value[:i] or None
self._append = self.value[j:] or None
break
# if both append and prepend are still None after looking
# at both lists, an insert statement will be created
if self._prepend is self._append is None:
self._assignments = self.value
self._analyzed = True
class MapUpdateClause(ContainerUpdateClause):
""" updates a map collection """
def __init__(self, field, value, operation=None, previous=None, column=None):
super(MapUpdateClause, self).__init__(field, value, operation, previous, column=column)
self._updates = None
def _analyze(self):
if self._operation == "update":
self._updates = self.value.keys()
else:
if self.previous is None:
self._updates = sorted([k for k, v in self.value.items()])
else:
self._updates = sorted([k for k, v in self.value.items() if v != self.previous.get(k)]) or None
self._analyzed = True
def get_context_size(self):
if not self._analyzed: self._analyze()
if self.previous is None and not self._updates:
return 1
return len(self._updates or []) * 2
def update_context(self, ctx):
if not self._analyzed: self._analyze()
ctx_id = self.context_id
if self.previous is None and not self._updates:
ctx[str(ctx_id)] = {}
else:
for key in self._updates or []:
val = self.value.get(key)
ctx[str(ctx_id)] = self._column.key_col.to_database(key) if self._column else key
ctx[str(ctx_id + 1)] = self._column.value_col.to_database(val) if self._column else val
ctx_id += 2
def __unicode__(self):
if not self._analyzed: self._analyze()
qs = []
ctx_id = self.context_id
if self.previous is None and not self._updates:
qs += ['"{}" = %({})s'.format(self.field, ctx_id)]
else:
for _ in self._updates or []:
qs += ['"{}"[%({})s] = %({})s'.format(self.field, ctx_id, ctx_id + 1)]
ctx_id += 2
return ', '.join(qs)
class CounterUpdateClause(ContainerUpdateClause):
def __init__(self, field, value, previous=None, column=None):
super(CounterUpdateClause, self).__init__(field, value, previous=previous, column=column)
self.previous = self.previous or 0
def get_context_size(self):
return 1
def update_context(self, ctx):
ctx[str(self.context_id)] = self._to_database(abs(self.value - self.previous))
def __unicode__(self):
delta = self.value - self.previous
sign = '-' if delta < 0 else '+'
return '"{0}" = "{0}" {1} %({2})s'.format(self.field, sign, self.context_id)
class BaseDeleteClause(BaseClause):
pass
class FieldDeleteClause(BaseDeleteClause):
""" deletes a field from a row """
def __init__(self, field):
super(FieldDeleteClause, self).__init__(field, None)
def __unicode__(self):
return '"{}"'.format(self.field)
def update_context(self, ctx):
pass
def get_context_size(self):
return 0
class MapDeleteClause(BaseDeleteClause):
""" removes keys from a map """
def __init__(self, field, value, previous=None):
super(MapDeleteClause, self).__init__(field, value)
self.value = self.value or {}
self.previous = previous or {}
self._analyzed = False
self._removals = None
def _analyze(self):
self._removals = sorted([k for k in self.previous if k not in self.value])
self._analyzed = True
def update_context(self, ctx):
if not self._analyzed: self._analyze()
for idx, key in enumerate(self._removals):
ctx[str(self.context_id + idx)] = key
def get_context_size(self):
if not self._analyzed: self._analyze()
return len(self._removals)
def __unicode__(self):
if not self._analyzed: self._analyze()
return ', '.join(['"{}"[%({})s]'.format(self.field, self.context_id + i) for i in range(len(self._removals))])
class BaseCQLStatement(UnicodeMixin):
""" The base cql statement class """
def __init__(self, table, consistency=None, timestamp=None, where=None):
super(BaseCQLStatement, self).__init__()
self.table = table
self.consistency = consistency
self.context_id = 0
self.context_counter = self.context_id
self.timestamp = timestamp
self.where_clauses = []
for clause in where or []:
self.add_where_clause(clause)
def add_where_clause(self, clause):
"""
adds a where clause to this statement
:param clause: the clause to add
:type clause: WhereClause
"""
if not isinstance(clause, WhereClause):
raise StatementException("only instances of WhereClause can be added to statements")
clause.set_context_id(self.context_counter)
self.context_counter += clause.get_context_size()
self.where_clauses.append(clause)
def get_context(self):
"""
returns the context dict for this statement
:rtype: dict
"""
ctx = {}
for clause in self.where_clauses or []:
clause.update_context(ctx)
return ctx
def get_context_size(self):
return len(self.get_context())
def update_context_id(self, i):
self.context_id = i
self.context_counter = self.context_id
for clause in self.where_clauses:
clause.set_context_id(self.context_counter)
self.context_counter += clause.get_context_size()
@property
def timestamp_normalized(self):
"""
we're expecting self.timestamp to be either a long, int, a datetime, or a timedelta
:return:
"""
if not self.timestamp:
return None
if isinstance(self.timestamp, six.integer_types):
return self.timestamp
if isinstance(self.timestamp, timedelta):
tmp = datetime.now() + self.timestamp
else:
tmp = self.timestamp
return int(time.mktime(tmp.timetuple()) * 1e+6 + tmp.microsecond)
def __unicode__(self):
raise NotImplementedError
def __repr__(self):
return self.__unicode__()
@property
def _where(self):
return 'WHERE {}'.format(' AND '.join([six.text_type(c) for c in self.where_clauses]))
class SelectStatement(BaseCQLStatement):
""" a cql select statement """
def __init__(self,
table,
fields=None,
count=False,
consistency=None,
where=None,
order_by=None,
limit=None,
allow_filtering=False):
"""
:param where
:type where list of cqlengine.statements.WhereClause
"""
super(SelectStatement, self).__init__(
table,
consistency=consistency,
where=where
)
self.fields = [fields] if isinstance(fields, six.string_types) else (fields or [])
self.count = count
self.order_by = [order_by] if isinstance(order_by, six.string_types) else order_by
self.limit = limit
self.allow_filtering = allow_filtering
def __unicode__(self):
qs = ['SELECT']
if self.count:
qs += ['COUNT(*)']
else:
qs += [', '.join(['"{}"'.format(f) for f in self.fields]) if self.fields else '*']
qs += ['FROM', self.table]
if self.where_clauses:
qs += [self._where]
if self.order_by and not self.count:
qs += ['ORDER BY {}'.format(', '.join(six.text_type(o) for o in self.order_by))]
if self.limit:
qs += ['LIMIT {}'.format(self.limit)]
if self.allow_filtering:
qs += ['ALLOW FILTERING']
return ' '.join(qs)
class AssignmentStatement(BaseCQLStatement):
""" value assignment statements """
def __init__(self,
table,
assignments=None,
consistency=None,
where=None,
ttl=None,
timestamp=None):
super(AssignmentStatement, self).__init__(
table,
consistency=consistency,
where=where,
)
self.ttl = ttl
self.timestamp = timestamp
# add assignments
self.assignments = []
for assignment in assignments or []:
self.add_assignment_clause(assignment)
def update_context_id(self, i):
super(AssignmentStatement, self).update_context_id(i)
for assignment in self.assignments:
assignment.set_context_id(self.context_counter)
self.context_counter += assignment.get_context_size()
def add_assignment_clause(self, clause):
"""
adds an assignment clause to this statement
:param clause: the clause to add
:type clause: AssignmentClause
"""
if not isinstance(clause, AssignmentClause):
raise StatementException("only instances of AssignmentClause can be added to statements")
clause.set_context_id(self.context_counter)
self.context_counter += clause.get_context_size()
self.assignments.append(clause)
@property
def is_empty(self):
return len(self.assignments) == 0
def get_context(self):
ctx = super(AssignmentStatement, self).get_context()
for clause in self.assignments:
clause.update_context(ctx)
return ctx
class InsertStatement(AssignmentStatement):
""" an cql insert select statement """
def __init__(self,
table,
assignments=None,
consistency=None,
where=None,
ttl=None,
timestamp=None,
if_not_exists=False):
super(InsertStatement, self).__init__(
table,
assignments=assignments,
consistency=consistency,
where=where,
ttl=ttl,
timestamp=timestamp)
self.if_not_exists = if_not_exists
def add_where_clause(self, clause):
raise StatementException("Cannot add where clauses to insert statements")
def __unicode__(self):
qs = ['INSERT INTO {}'.format(self.table)]
# get column names and context placeholders
fields = [a.insert_tuple() for a in self.assignments]
columns, values = zip(*fields)
qs += ["({})".format(', '.join(['"{}"'.format(c) for c in columns]))]
qs += ['VALUES']
qs += ["({})".format(', '.join(['%({})s'.format(v) for v in values]))]
if self.if_not_exists:
qs += ["IF NOT EXISTS"]
if self.ttl:
qs += ["USING TTL {}".format(self.ttl)]
if self.timestamp:
qs += ["USING TIMESTAMP {}".format(self.timestamp_normalized)]
return ' '.join(qs)
class UpdateStatement(AssignmentStatement):
""" an cql update select statement """
def __init__(self,
table,
assignments=None,
consistency=None,
where=None,
ttl=None,
timestamp=None,
transactions=None):
super(UpdateStatement, self). __init__(table,
assignments=assignments,
consistency=consistency,
where=where,
ttl=ttl,
timestamp=timestamp)
# Add iff statements
self.transactions = []
for transaction in transactions or []:
self.add_transaction_clause(transaction)
def __unicode__(self):
qs = ['UPDATE', self.table]
using_options = []
if self.ttl:
using_options += ["TTL {}".format(self.ttl)]
if self.timestamp:
using_options += ["TIMESTAMP {}".format(self.timestamp_normalized)]
if using_options:
qs += ["USING {}".format(" AND ".join(using_options))]
qs += ['SET']
qs += [', '.join([six.text_type(c) for c in self.assignments])]
if self.where_clauses:
qs += [self._where]
if len(self.transactions) > 0:
qs += [self._get_transactions()]
return ' '.join(qs)
def add_transaction_clause(self, clause):
"""
Adds a iff clause to this statement
:param clause: The clause that will be added to the iff statement
:type clause: TransactionClause
"""
if not isinstance(clause, TransactionClause):
raise StatementException('only instances of AssignmentClause can be added to statements')
clause.set_context_id(self.context_counter)
self.context_counter += clause.get_context_size()
self.transactions.append(clause)
def get_context(self):
ctx = super(UpdateStatement, self).get_context()
for clause in self.transactions or []:
clause.update_context(ctx)
return ctx
def _get_transactions(self):
return 'IF {}'.format(' AND '.join([six.text_type(c) for c in self.transactions]))
def update_context_id(self, i):
super(UpdateStatement, self).update_context_id(i)
for transaction in self.transactions:
transaction.set_context_id(self.context_counter)
self.context_counter += transaction.get_context_size()
class DeleteStatement(BaseCQLStatement):
""" a cql delete statement """
def __init__(self, table, fields=None, consistency=None, where=None, timestamp=None):
super(DeleteStatement, self).__init__(
table,
consistency=consistency,
where=where,
timestamp=timestamp
)
self.fields = []
if isinstance(fields, six.string_types):
fields = [fields]
for field in fields or []:
self.add_field(field)
def update_context_id(self, i):
super(DeleteStatement, self).update_context_id(i)
for field in self.fields:
field.set_context_id(self.context_counter)
self.context_counter += field.get_context_size()
def get_context(self):
ctx = super(DeleteStatement, self).get_context()
for field in self.fields:
field.update_context(ctx)
return ctx
def add_field(self, field):
if isinstance(field, six.string_types):
field = FieldDeleteClause(field)
if not isinstance(field, BaseClause):
raise StatementException("only instances of AssignmentClause can be added to statements")
field.set_context_id(self.context_counter)
self.context_counter += field.get_context_size()
self.fields.append(field)
def __unicode__(self):
qs = ['DELETE']
if self.fields:
qs += [', '.join(['{}'.format(f) for f in self.fields])]
qs += ['FROM', self.table]
delete_option = []
if self.timestamp:
delete_option += ["TIMESTAMP {}".format(self.timestamp_normalized)]
if delete_option:
qs += [" USING {} ".format(" AND ".join(delete_option))]
if self.where_clauses:
qs += [self._where]
return ' '.join(qs)