deb-murano/murano/dsl/lhs_expression.py
Stan Lagun 6dfeee7e69 Function caller was incorrect when called from Parallel block
Current instruction is tracked as a value in yaql context.
But in Parallel block individual instructions executed in separate
threads. As a result when those threads get scheduled current
instruction in caller context already changes to the last one
(which is a synchronization point for the Parallel block).

To solve this all spawned threads need to work in their own
dedicated child contexts. Then each of those contexts will have
its own "current instruction". However this also brings a side effect:
all local variable modifications made by spawned threads will
be go to those new contexts and will be lost upon exit from Parallel.
To solve this context that local variable need to be in is marked with
special flag. When executing "$var: value" expressions DSL will scan
context chain up to the context with that flag. Currently the only
context with the flag is a method context that defines local variable scope.

Change-Id: I0647915c104dfe4e00dd86c17726245d1bbc3beb
Closes-Bug: #1497772
2015-09-20 19:00:06 +00:00

132 lines
4.8 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 itertools
import types
from yaql.language import specs
from yaql.language import utils
from yaql.language import yaqltypes
from murano.dsl import constants
from murano.dsl import dsl_types
from murano.dsl import exceptions
from murano.dsl import yaql_integration
class LhsExpression(object):
class Property(object):
def __init__(self, getter, setter):
self._getter = getter
self._setter = setter
def get(self):
return self._getter()
def set(self, value):
self._setter(value)
def __init__(self, expression):
self._expression = expression
def _create_context(self, root_context):
@specs.parameter('name', yaqltypes.StringConstant())
def get_context_data(name):
def set_data(value):
if not name or name == '$' or name == '$this':
raise ValueError('Cannot assign to {0}'.format(name))
ctx = root_context
while constants.CTX_VARIABLE_SCOPE not in ctx:
ctx = ctx.parent
ctx[name] = value
return LhsExpression.Property(
lambda: root_context[name], set_data)
@specs.parameter('this', LhsExpression.Property)
@specs.parameter('key', yaqltypes.Keyword())
def attribution(this, key):
def setter(src_property, value):
src = src_property.get()
if isinstance(src, utils.MappingType):
src_property.set(
utils.FrozenDict(
itertools.chain(
src.iteritems(),
((key, value),))))
elif isinstance(src, dsl_types.MuranoObject):
src.set_property(key, value, root_context)
else:
raise ValueError(
'attribution may only be applied to '
'objects and dictionaries')
def getter(src):
if isinstance(src, utils.MappingType):
return src.get(key, {})
elif isinstance(src, dsl_types.MuranoObject):
self._current_obj = src
self._current_obj_name = key
try:
return src.get_property(key, root_context)
except exceptions.UninitializedPropertyAccessError:
return {}
else:
raise ValueError(
'attribution may only be applied to '
'objects and dictionaries')
return LhsExpression.Property(
lambda: getter(this.get()),
lambda value: setter(this, value))
@specs.parameter('this', LhsExpression.Property)
@specs.parameter('index', yaqltypes.Lambda(with_context=True))
def indexation(this, index):
index = index(root_context)
def getter(src):
if utils.is_sequence(src):
return src[index]
else:
raise ValueError('indexation may only be applied to lists')
def setter(src_property, value):
src = src_property.get()
if utils.is_sequence(src):
src_property.set(src[:index] + (value,) + src[index + 1:])
if isinstance(index, types.IntType):
return LhsExpression.Property(
lambda: getter(this.get()),
lambda value: setter(this, value))
else:
return attribution(this, index)
context = yaql_integration.create_empty_context()
context.register_function(get_context_data, '#get_context_data')
context.register_function(attribution, '#operator_.')
context.register_function(indexation, '#indexer')
return context
def __call__(self, value, context):
new_context = self._create_context(context)
new_context[''] = context['$']
self._current_obj = None
self._current_obj_name = None
property = self._expression(context=new_context)
property.set(value)