deb-murano/murano/dsl/expressions.py

115 lines
3.4 KiB
Python

# Copyright (c) 2014 Mirantis, Inc.
#
# 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 six
from murano.dsl import dsl_exception
from murano.dsl import helpers
from murano.dsl import lhs_expression
from murano.dsl import yaql_expression
_macros = []
class InstructionStub(object):
def __init__(self, title, position):
self._title = title
self.source_file_position = position
def __str__(self):
return self._title
def register_macro(cls):
_macros.append(cls)
class DslExpression(object):
def execute(self, context):
pass
class Statement(DslExpression):
def __init__(self, statement):
if isinstance(statement, yaql_expression.YaqlExpression):
key = None
value = statement
elif isinstance(statement, dict):
if len(statement) != 1:
raise SyntaxError()
key = list(statement.keys())[0]
value = statement[key]
else:
raise SyntaxError()
self._destination = lhs_expression.LhsExpression(key) if key else None
self._expression = value
@property
def destination(self):
return self._destination
@property
def expression(self):
return self._expression
def execute(self, context):
try:
result = helpers.evaluate(self.expression, context)
if self.destination:
self.destination(result, context)
return result
except dsl_exception.MuranoPlException:
raise
except Exception as e:
raise dsl_exception.MuranoPlException.from_python_exception(
e, context)
def parse_expression(expr):
result = None
if isinstance(expr, yaql_expression.YaqlExpression):
result = Statement(expr)
elif isinstance(expr, dict):
kwds = {}
for key, value in six.iteritems(expr):
if isinstance(key, yaql_expression.YaqlExpression):
if result is not None:
raise ValueError()
result = Statement(expr)
else:
kwds[key] = value
if result is None:
for cls in _macros:
try:
macro = cls(**kwds)
position = None
title = 'block construct'
if hasattr(expr, 'source_file_position'):
position = expr.source_file_position
if '__str__' in cls.__dict__:
title = str(macro)
macro.virtual_instruction = InstructionStub(
title, position)
return macro
except TypeError:
continue
if result is None:
raise SyntaxError(
'Syntax is incorrect in expression: {0}'.format(expr))
return result