121 lines
3.2 KiB
Python
121 lines
3.2 KiB
Python
# Copyright 2015 - Mirantis, Inc.
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# Copyright 2020 - Nokia Software.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import abc
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from mistral import config as cfg
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from mistral import exceptions as exc
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from mistral import utils
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from oslo_utils import importutils
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from stevedore import driver
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from stevedore import extension
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_PYV8 = importutils.try_import('PyV8')
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_V8EVAL = importutils.try_import('v8eval')
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_PY_MINI_RACER = importutils.try_import('py_mini_racer.py_mini_racer')
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_EVALUATOR = None
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class JSEvaluator(object):
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@classmethod
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@abc.abstractmethod
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def evaluate(cls, script, context):
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"""Executes given JavaScript.
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:param script: The text of JavaScript snippet that needs to be
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executed.
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:param context: This object will be assigned to the $ javascript
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variable.
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:return result of evaluated javascript code.
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:raise MistralException: if corresponding js library is not installed.
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"""
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pass
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class PyV8Evaluator(JSEvaluator):
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@classmethod
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def evaluate(cls, script, ctx):
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if not _PYV8:
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raise exc.MistralException(
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"PyV8 module is not available. Please install PyV8."
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)
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with _PYV8.JSContext() as js_ctx:
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# Prepare data context and way for interaction with it.
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js_ctx.eval('$ = %s' % utils.to_json_str(ctx))
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result = js_ctx.eval(script)
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return _PYV8.convert(result)
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class V8EvalEvaluator(JSEvaluator):
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@classmethod
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def evaluate(cls, script, ctx):
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if not _V8EVAL:
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raise exc.MistralException(
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"v8eval module is not available. Please install v8eval."
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)
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v8 = _V8EVAL.V8()
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ctx_str = utils.to_json_str(ctx)
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return v8.eval(
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('$ = %s; %s' % (ctx_str, script)).encode(encoding='UTF-8')
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)
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class PyMiniRacerEvaluator(JSEvaluator):
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@classmethod
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def evaluate(cls, script, ctx):
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if not _PY_MINI_RACER:
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raise exc.MistralException(
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"PyMiniRacer module is not available. Please install "
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"PyMiniRacer."
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)
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js_ctx = _PY_MINI_RACER.MiniRacer()
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return js_ctx.eval(
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'$ = {}; {}'.format(utils.to_json_str(ctx), script)
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)
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_mgr = extension.ExtensionManager(
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namespace='mistral.expression.evaluators',
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invoke_on_load=False
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)
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def get_js_evaluator():
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global _EVALUATOR
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if not _EVALUATOR:
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mgr = driver.DriverManager(
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'mistral.js.implementation',
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cfg.CONF.js_implementation,
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invoke_on_load=True
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)
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_EVALUATOR = mgr.driver
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return _EVALUATOR
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def evaluate(script, ctx):
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return get_js_evaluator().evaluate(script, ctx)
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