b563e5898f
Only keep the top level validation/evaluation log is enough for debugging. Change-Id: I22d18aeeafcf68aaa6f55da1c943b282f001ef82
139 lines
4.3 KiB
Python
139 lines
4.3 KiB
Python
# Copyright 2016 - Brocade Communications Systems, Inc.
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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 re
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import jinja2
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from jinja2 import parser as jinja_parse
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from oslo_log import log as logging
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import six
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from mistral import exceptions as exc
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from mistral.expressions.base_expression import Evaluator
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from mistral.utils import expression_utils
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LOG = logging.getLogger(__name__)
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JINJA_REGEXP = '({{(.*)}})'
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JINJA_BLOCK_REGEXP = '({%(.*)%})'
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_environment = jinja2.Environment(
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undefined=jinja2.StrictUndefined,
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trim_blocks=True,
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lstrip_blocks=True
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)
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_filters = expression_utils.get_custom_functions()
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for name in _filters:
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_environment.filters[name] = _filters[name]
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class JinjaEvaluator(Evaluator):
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_env = _environment.overlay()
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@classmethod
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def validate(cls, expression):
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if not isinstance(expression, six.string_types):
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raise exc.JinjaEvaluationException(
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"Unsupported type '%s'." % type(expression)
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)
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try:
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parser = jinja_parse.Parser(cls._env, expression, state='variable')
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parser.parse_expression()
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except jinja2.exceptions.TemplateError as e:
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raise exc.JinjaGrammarException(
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"Syntax error '%s'." % str(e)
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)
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@classmethod
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def evaluate(cls, expression, data_context):
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opts = {'undefined_to_none': False}
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ctx = expression_utils.get_jinja_context(data_context)
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try:
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result = cls._env.compile_expression(expression, **opts)(**ctx)
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# For StrictUndefined values, UndefinedError only gets raised when
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# the value is accessed, not when it gets created. The simplest way
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# to access it is to try and cast it to string.
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str(result)
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except Exception as e:
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raise exc.JinjaEvaluationException(
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"Can not evaluate Jinja expression [expression=%s, error=%s"
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", data=%s]" % (expression, str(e), data_context)
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)
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return result
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@classmethod
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def is_expression(cls, s):
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# The class should only be called from within InlineJinjaEvaluator. The
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# return value prevents the class from being accidentally added as
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# Extension
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return False
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class InlineJinjaEvaluator(Evaluator):
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# The regular expression for Jinja variables and blocks
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find_expression_pattern = re.compile(JINJA_REGEXP)
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find_block_pattern = re.compile(JINJA_BLOCK_REGEXP)
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_env = _environment.overlay()
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@classmethod
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def validate(cls, expression):
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if not isinstance(expression, six.string_types):
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raise exc.JinjaEvaluationException(
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"Unsupported type '%s'." % type(expression)
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)
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try:
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cls._env.parse(expression)
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except jinja2.exceptions.TemplateError as e:
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raise exc.JinjaGrammarException(
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"Syntax error '%s'." % str(e)
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)
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@classmethod
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def evaluate(cls, expression, data_context):
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LOG.debug(
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"Start to evaluate Jinja expression. [expression='%s', context=%s]"
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% (expression, data_context)
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)
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patterns = cls.find_expression_pattern.findall(expression)
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if patterns[0][0] == expression:
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result = JinjaEvaluator.evaluate(patterns[0][1], data_context)
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else:
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ctx = expression_utils.get_jinja_context(data_context)
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result = cls._env.from_string(expression).render(**ctx)
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LOG.debug(
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"Finished evaluation. [expression='%s', result: %s]" %
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(expression, result)
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)
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return result
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@classmethod
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def is_expression(cls, s):
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return (cls.find_expression_pattern.search(s) or
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cls.find_block_pattern.search(s))
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