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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright (c) 2017 Cisco and/or its affiliates.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import re
import sys
import pyparsing as pp
from netmodel.model.query import Query
from netmodel.model.filter import Filter
from netmodel.model.predicate import Predicate
DEBUG = False
def debug(args):
if DEBUG: print(args)
class SQLParser(object):
def __init__(self):
"""
Our simple BNF:
SELECT [fields[*] FROM table WHERE clause
"""
integer = pp.Combine(pp.Optional(pp.oneOf("+ -")) +
pp.Word(pp.nums)).setParseAction(lambda t:int(t[0]))
floatNumber = pp.Regex(r'\d+(\.\d*)?([eE]\d+)?')
point = pp.Literal(".")
e = pp.CaselessLiteral("E")
kw_store = pp.CaselessKeyword('=')
kw_select = pp.CaselessKeyword('select')
kw_subscribe = pp.CaselessKeyword('subscribe')
kw_update = pp.CaselessKeyword('update')
kw_insert = pp.CaselessKeyword('insert')
kw_delete = pp.CaselessKeyword('delete')
kw_execute = pp.CaselessKeyword('execute')
kw_from = pp.CaselessKeyword('from')
kw_into = pp.CaselessKeyword('into')
kw_where = pp.CaselessKeyword('where')
kw_at = pp.CaselessKeyword('at')
kw_set = pp.CaselessKeyword('set')
kw_true = pp.CaselessKeyword('true').setParseAction(lambda t: 1)
kw_false = pp.CaselessKeyword('false').setParseAction(lambda t: 0)
kw_with = pp.CaselessKeyword('with')
sum_function = pp.CaselessLiteral('sum')
# Regex string representing the set of possible operators
# Example : ">=|<=|!=|>|<|="
OPERATOR_RX = "(?i)%s" % '|'.join([re.sub('\|', '\|', o) \
for o in Predicate.operators.keys()])
# predicate
field = pp.Word(pp.alphanums + '_' + '.')
operator = pp.Regex(OPERATOR_RX).setName("operator")
variable = pp.Literal('$').suppress() + pp.Word(pp.alphanums \
+ '_' + '.').setParseAction(lambda t: "$%s" % t[0])
filename = pp.Regex('([a-z]+?://)?(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\(\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+')
obj = pp.Forward()
value = obj | pp.QuotedString('"') | pp.QuotedString("'") | \
kw_true | kw_false | integer | variable
def handle_value_list(s, l, t):
t = t.asList()
new_t = tuple(t)
debug("[handle_value_list] s = %(s)s ** l = %(l)s ** t = %(t)s" \
% locals())
debug(" new_t = %(new_t)s" % locals())
return new_t
value_list = value \
| (pp.Literal("[").suppress() + pp.Literal("]").suppress()) \
.setParseAction(lambda s, l, t: [[]]) \
| pp.Literal("[").suppress() \
+ pp.delimitedList(value).setParseAction(handle_value_list) \
+ pp.Literal("]") \
.suppress()
table = pp.Word(pp.alphanums + ':_-/').setResultsName('object_name')
field_list = pp.Literal("*") | pp.delimitedList(field).setParseAction(lambda tokens: set(tokens))
assoc = (field + pp.Literal(":").suppress() + value_list).setParseAction(lambda tokens: [tokens.asList()])
obj << pp.Literal("{").suppress() \
+ pp.delimitedList(assoc).setParseAction(lambda t: dict(t.asList())) \
+ pp.Literal("}").suppress()
# PARAMETER (SET)
# X = Y --> t=(X, Y)
def handle_param(s, l, t):
t = t.asList()
assert len(t) == 2
new_t = tuple(t)
debug("[handle_param] s = %(s)s ** l = %(l)s ** t = %(t)s" % locals())
debug(" new_t = %(new_t)s" % locals())
return new_t
param = (field + pp.Literal("=").suppress() + value_list) \
.setParseAction(handle_param)
# PARAMETERS (SET)
# PARAMETER[, PARAMETER[, ...]] --> dict()
def handle_parameters(s, l, t):
t = t.asList()
new_t = dict(t) if t else dict()
debug("[handle_parameters] s = %(s)s ** l = %(l)s ** t = %(t)s" % locals())
debug(" new_t = %(new_t)s" % locals())
return new_t
parameters = pp.delimitedList(param) \
.setParseAction(handle_parameters)
predicate = (field + operator + value_list).setParseAction(self.handlePredicate)
# For the time being, we only support simple filters and not full clauses
filter = pp.delimitedList(predicate, delim='&&').setParseAction(lambda tokens: Filter(tokens.asList()))
datetime = pp.Regex(r'....-..-.. ..:..:..')
timestamp = pp.CaselessKeyword('now') | datetime
store_elt = (variable.setResultsName("variable") + kw_store.suppress())
fields_elt = field_list.setResultsName('field_names')
aggregate_elt = sum_function.setResultsName('aggregate') + pp.Literal("(").suppress() + fields_elt + pp.Literal(")").suppress()
select_elt = (kw_select.suppress() + fields_elt)
subscribe_elt = (kw_subscribe.suppress() + fields_elt)
where_elt = (kw_where.suppress() + filter.setResultsName('filter'))
set_elt = (kw_set.suppress() + parameters.setResultsName('params'))
at_elt = (kw_at.suppress() + timestamp.setResultsName('timestamp'))
into_elt = (kw_into.suppress() + filename.setResultsName('receiver'))
# SELECT [SUM(]*|field_list[)] [AT timestamp] FROM table [WHERE clause]
select = (
pp.Optional(store_elt)\
+ kw_select.suppress() \
+ pp.Optional(into_elt) \
+ (aggregate_elt | fields_elt)\
+ pp.Optional(at_elt)\
+ kw_from.suppress()\
+ table\
+ pp.Optional(where_elt)
).setParseAction(lambda args: self.action(args, 'select'))
subscribe = (
pp.Optional(store_elt) \
+ kw_subscribe.suppress() \
+ pp.Optional(into_elt) \
+ (aggregate_elt | fields_elt) \
+ pp.Optional(at_elt)\
+ kw_from.suppress()\
+ table\
+ pp.Optional(where_elt)
+ pp.Optional(set_elt)
).setParseAction(lambda args: self.action(args, 'subscribe'))
# UPDATE table SET parameters [WHERE clause] [SELECT *|field_list]
update = (
kw_update \
+ table \
+ set_elt \
+ pp.Optional(where_elt) \
+ pp.Optional(select_elt)
).setParseAction(lambda args: self.action(args, 'update'))
# INSERT INTO table SET parameters [SELECT *|field_list]
insert = (
kw_insert + kw_into + table
+ set_elt
+ pp.Optional(select_elt)
).setParseAction(lambda args: self.action(args, 'insert'))
# DELETE FROM table [WHERE clause]
delete = (
kw_delete \
+ kw_from \
+ table \
+ pp.Optional(where_elt)
).setParseAction(lambda args: self.action(args, 'delete'))
#
execute = (
kw_execute + kw_from + table
+ set_elt
+ pp.Optional(where_elt)
).setParseAction(lambda args: self.action(args, 'execute'))
annotation = pp.Optional(kw_with + \
parameters.setResultsName('annotation'))
self.bnf = (select | update | insert | delete | subscribe | execute) \
+ annotation
# For reusing parser:
self.filter = filter
def action(self, args, action):
args['action'] = action
def handlePredicate(self, args):
return Predicate(*args)
def parse(self, string):
result = self.bnf.parseString(string, parseAll = True)
return dict(result.items())
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