deb-murano/murano/dsl/macros.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

263 lines
8.9 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 types
from murano.dsl import constants
from murano.dsl import dsl_exception
from murano.dsl import exceptions
from murano.dsl import expressions
from murano.dsl import helpers
from murano.dsl import yaql_expression
class CodeBlock(expressions.DslExpression):
def __init__(self, body):
if not isinstance(body, types.ListType):
body = [body]
self.code_block = map(expressions.parse_expression, body)
def execute(self, context):
for expr in self.code_block:
if hasattr(expr, 'virtual_instruction'):
instruction = expr.virtual_instruction
context[constants.CTX_CURRENT_INSTRUCTION] = instruction
try:
expr.execute(context)
except (dsl_exception.MuranoPlException,
exceptions.InternalFlowException):
raise
except Exception as ex:
raise dsl_exception.MuranoPlException.from_python_exception(
ex, context)
class MethodBlock(CodeBlock):
def __init__(self, body, name=None):
super(MethodBlock, self).__init__(body)
self._name = name
def execute(self, context):
new_context = context.create_child_context()
new_context[constants.CTX_VARIABLE_SCOPE] = True
try:
super(MethodBlock, self).execute(new_context)
except exceptions.ReturnException as e:
return e.value
except exceptions.BreakException:
raise exceptions.DslInvalidOperationError(
'Break cannot be used on method level')
except exceptions.ContinueException:
raise exceptions.DslInvalidOperationError(
'Continue cannot be used on method level')
else:
return None
class ReturnMacro(expressions.DslExpression):
def __init__(self, Return):
self._value = Return
def execute(self, context):
raise exceptions.ReturnException(
helpers.evaluate(self._value, context))
class BreakMacro(expressions.DslExpression):
def __init__(self, Break):
if Break:
raise exceptions.DslSyntaxError('Break cannot have value')
def execute(self, context):
raise exceptions.BreakException()
class ContinueMacro(expressions.DslExpression):
def __init__(self, Continue):
if Continue:
raise exceptions.DslSyntaxError('Continue cannot have value')
def execute(self, context):
raise exceptions.ContinueException()
class ParallelMacro(CodeBlock):
def __init__(self, Parallel, Limit=None):
super(ParallelMacro, self).__init__(Parallel)
self._limit = Limit or len(self.code_block)
def execute(self, context):
if not self.code_block:
return
limit = helpers.evaluate(self._limit, context)
helpers.parallel_select(
self.code_block,
lambda expr: expr.execute(context.create_child_context()),
limit)
class IfMacro(expressions.DslExpression):
def __init__(self, If, Then, Else=None):
if not isinstance(If, yaql_expression.YaqlExpression):
raise exceptions.DslSyntaxError(
'Condition must be of expression type')
self._code1 = CodeBlock(Then)
self._code2 = None if Else is None else CodeBlock(Else)
self._condition = If
def execute(self, context):
res = self._condition(context)
if not isinstance(res, types.BooleanType):
raise exceptions.DslInvalidOperationError(
'Condition must be evaluated to boolean type')
if res:
self._code1.execute(context)
elif self._code2 is not None:
self._code2.execute(context)
class WhileDoMacro(expressions.DslExpression):
def __init__(self, While, Do):
if not isinstance(While, yaql_expression.YaqlExpression):
raise TypeError()
self._code = CodeBlock(Do)
self._condition = While
def execute(self, context):
while True:
res = self._condition(context)
if not isinstance(res, types.BooleanType):
raise exceptions.DslSyntaxError(
'Condition must be of expression type')
try:
if res:
self._code.execute(context)
else:
break
except exceptions.BreakException:
break
except exceptions.ContinueException:
continue
class ForMacro(expressions.DslExpression):
def __init__(self, For, In, Do):
if not isinstance(For, types.StringTypes):
raise exceptions.DslSyntaxError(
'For value must be of string type')
self._code = CodeBlock(Do)
self._var = For
self._collection = In
def execute(self, context):
collection = helpers.evaluate(self._collection, context)
for t in collection:
context[self._var] = t
try:
self._code.execute(context)
except exceptions.BreakException:
break
except exceptions.ContinueException:
continue
class RepeatMacro(expressions.DslExpression):
def __init__(self, Repeat, Do):
if not isinstance(Repeat, (int, yaql_expression.YaqlExpression)):
raise exceptions.DslSyntaxError(
'Repeat value must be either int or expression')
self._count = Repeat
self._code = CodeBlock(Do)
def execute(self, context):
count = helpers.evaluate(self._count, context)
for _ in range(0, count):
try:
self._code.execute(context)
except exceptions.BreakException:
break
except exceptions.ContinueException:
continue
class MatchMacro(expressions.DslExpression):
def __init__(self, Match, Value, Default=None):
if not isinstance(Match, types.DictionaryType):
raise exceptions.DslSyntaxError(
'Match value must be of dictionary type')
self._switch = Match
self._value = Value
self._default = None if Default is None else CodeBlock(Default)
def execute(self, context):
match_value = helpers.evaluate(self._value, context)
for key, value in self._switch.iteritems():
if key == match_value:
CodeBlock(value).execute(context)
return
if self._default is not None:
self._default.execute(context)
class SwitchMacro(expressions.DslExpression):
def __init__(self, Switch, Default=None):
if not isinstance(Switch, types.DictionaryType):
raise exceptions.DslSyntaxError(
'Switch value must be of dictionary type')
self._switch = Switch
for key in self._switch.iterkeys():
if not isinstance(key, (yaql_expression.YaqlExpression,
types.BooleanType)):
raise exceptions.DslSyntaxError(
'Switch cases must be must be either '
'boolean or expression')
self._default = None if Default is None else CodeBlock(Default)
def execute(self, context):
matched = False
for key, value in self._switch.iteritems():
res = helpers.evaluate(key, context)
if not isinstance(res, types.BooleanType):
raise exceptions.DslInvalidOperationError(
'Switch case must be evaluated to boolean type')
if res:
matched = True
CodeBlock(value).execute(context)
if self._default is not None and not matched:
self._default.execute(context)
class DoMacro(expressions.DslExpression):
def __init__(self, Do):
self._code = CodeBlock(Do)
def execute(self, context):
self._code.execute(context)
def register():
expressions.register_macro(DoMacro)
expressions.register_macro(ReturnMacro)
expressions.register_macro(BreakMacro)
expressions.register_macro(ContinueMacro)
expressions.register_macro(ParallelMacro)
expressions.register_macro(IfMacro)
expressions.register_macro(WhileDoMacro)
expressions.register_macro(ForMacro)
expressions.register_macro(RepeatMacro)
expressions.register_macro(MatchMacro)
expressions.register_macro(SwitchMacro)