deb-murano/murano/dsl/linked_context.py
Stan Lagun 16030aeec8 yaql context versioning
This commit reworks mechanism how context chain
is built at each point. The goal was to make
entire chain be dependent on format version
number. This would allow for example to use
yaql 1.0 legacy mode context for MuranoPL/1.0
and not to use it for 2.0.

Not the entire chain is built on demand up to the
root instead of attaching to existed parent context
as it was before. DSL host (engine) is no more
required to have custom MuranoDslExecutor implementation
but a new ContextManager interface that is used
to control contexts on each layer. Engine uses
this interface to register system classes and
engine level yaql functions. Also a ContextManager
is a foundation for method mocking because now
all MuranoPL methods are yaql functions stored
in context and with ContextManager it is possible
to inject/replace function in each scope (
global, package, class, object)

Partially implements: blueprint murano-versioning

Change-Id: I0a553e8044061fe780a83bc04d70b8f80580988f
2015-09-04 14:37:14 +00:00

70 lines
2.5 KiB
Python

# Copyright (c) 2015 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.
from yaql.language import contexts
from yaql.language import utils
class LinkedContext(contexts.ContextBase):
"""Context that is as a proxy to another context but has its own parent."""
def __init__(self, parent_context, linked_context, convention=None):
self.linked_context = linked_context
if linked_context.parent:
super(LinkedContext, self).__init__(
LinkedContext(parent_context, linked_context.parent,
convention), convention)
else:
super(LinkedContext, self).__init__(parent_context, convention)
def register_function(self, spec, *args, **kwargs):
return self.linked_context.register_function(spec, *args, **kwargs)
def keys(self):
return self.linked_context.keys()
def get_data(self, name, default=None, ask_parent=True):
result = self.linked_context.get_data(
name, default=utils.NO_VALUE, ask_parent=False)
if result is utils.NO_VALUE:
if not ask_parent or not self.parent:
return default
return self.parent.get_data(name, default=default, ask_parent=True)
return result
def get_functions(self, name, predicate=None, use_convention=False):
return self.linked_context.get_functions(
name, predicate=predicate, use_convention=use_convention)
def delete_function(self, spec):
return self.linked_context.delete_function(spec)
def __contains__(self, item):
return item in self.linked_context
def __delitem__(self, name):
del self.linked_context[name]
def __setitem__(self, name, value):
self.linked_context[name] = value
def create_child_context(self):
return type(self.linked_context)(self)
def link(parent_context, context):
if not context:
return parent_context
return LinkedContext(parent_context, context)