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Posted to commits@airflow.apache.org by GitBox <gi...@apache.org> on 2020/11/03 13:45:25 UTC
[GitHub] [airflow] ashmeet13 commented on a change in pull request #11241: Create Undefined Jinja Variables Rule
ashmeet13 commented on a change in pull request #11241:
URL: https://github.com/apache/airflow/pull/11241#discussion_r516008427
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File path: airflow/upgrade/rules/undefined_jinja_varaibles.py
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@@ -0,0 +1,121 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you 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 __future__ import absolute_import
+
+import re
+
+import jinja2
+import six
+
+from airflow import conf
+from airflow.models import DagBag, TaskInstance
+from airflow.upgrade.rules.base_rule import BaseRule
+from airflow.utils import timezone
+
+
+class UndefinedJinjaVariablesRule(BaseRule):
+
+ title = "Jinja Template Variables cannot be undefined"
+
+ description = """\
+Jinja Templates have been updated to the following rule - jinja2.StrictUndefined
+With this change a task will fail if it recieves any undefined variables.
+"""
+
+ def _check_rendered_content(self, rendered_content):
+ """Replicates the logic in BaseOperator.render_template() to
+ cover all the cases needed to be checked.
+ """
+ if isinstance(rendered_content, six.string_types):
+ return set(re.findall(r"{{(.*?)}}", rendered_content))
+
+ elif isinstance(rendered_content, (tuple, list, set)):
+ debug_error_messages = set()
+ for element in rendered_content:
+ debug_error_messages.union(self._check_rendered_content(element))
+ return debug_error_messages
+
+ elif isinstance(rendered_content, dict):
+ debug_error_messages = set()
+ for key, value in rendered_content.items():
+ debug_error_messages.union(self._check_rendered_content(str(value)))
+ return debug_error_messages
+
+ def _render_task_content(self, task, content, context):
+ completed_rendering = False
+ errors_while_rendering = []
+ while not completed_rendering:
+ # Catch errors such as {{ object.element }} where
+ # object is not defined
+ try:
+ renderend_content = task.render_template(content, context)
+ completed_rendering = True
+ except Exception as e:
+ undefined_variable = re.sub(" is undefined", "", str(e))
+ undefined_variable = re.sub("'", "", undefined_variable)
+ context[undefined_variable] = dict()
+ message = "Could not find the object '{}'".format(undefined_variable)
+ errors_while_rendering.append(message)
+ return renderend_content, errors_while_rendering
+
+ def _task_level_(self, task):
+ messages = {}
+ task_instance = TaskInstance(task=task, execution_date=timezone.utcnow())
+ context = task_instance.get_template_context()
+ for attr_name in task.template_fields:
+ content = getattr(task, attr_name)
+ if content:
+ rendered_content, errors_while_rendering = self._render_task_content(
+ task, content, context
+ )
+ debug_error_messages = list(
+ self._check_rendered_content(rendered_content)
+ )
+ messages[attr_name] = errors_while_rendering + debug_error_messages
+
+ return messages
+
+ def _dag_level_(self, dag):
+ dag.template_undefined = jinja2.DebugUndefined
+ tasks = dag.tasks
+ messages = {}
+ for task in tasks:
+ error_messages = self._task_level_(task)
+ messages[task.task_id] = error_messages
+ return messages
+
+ def check(self, dagbag=None):
+ if not dagbag:
+ dag_folder = conf.get("core", "dags_folder")
+ dagbag = DagBag(dag_folder)
+ dags = dagbag.dags
+ messages = []
+ for dag_id, dag in dags.items():
+ dag_messages = self._dag_level_(dag)
Review comment:
I missed this comment - my fault.
How exactly would we check this?
My thought process -
This would require the check to read the Python scripts in which the DAGs have been defined. Then read line by line where the DAG is defined and then check whether `template_undefined` is defined or not.
##########
File path: airflow/upgrade/rules/undefined_jinja_varaibles.py
##########
@@ -0,0 +1,121 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you 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 __future__ import absolute_import
+
+import re
+
+import jinja2
+import six
+
+from airflow import conf
+from airflow.models import DagBag, TaskInstance
+from airflow.upgrade.rules.base_rule import BaseRule
+from airflow.utils import timezone
+
+
+class UndefinedJinjaVariablesRule(BaseRule):
+
+ title = "Jinja Template Variables cannot be undefined"
+
+ description = """\
+Jinja Templates have been updated to the following rule - jinja2.StrictUndefined
+With this change a task will fail if it recieves any undefined variables.
+"""
+
+ def _check_rendered_content(self, rendered_content):
+ """Replicates the logic in BaseOperator.render_template() to
+ cover all the cases needed to be checked.
+ """
+ if isinstance(rendered_content, six.string_types):
+ return set(re.findall(r"{{(.*?)}}", rendered_content))
+
+ elif isinstance(rendered_content, (tuple, list, set)):
+ debug_error_messages = set()
+ for element in rendered_content:
+ debug_error_messages.union(self._check_rendered_content(element))
+ return debug_error_messages
+
+ elif isinstance(rendered_content, dict):
+ debug_error_messages = set()
+ for key, value in rendered_content.items():
+ debug_error_messages.union(self._check_rendered_content(str(value)))
+ return debug_error_messages
+
+ def _render_task_content(self, task, content, context):
+ completed_rendering = False
+ errors_while_rendering = []
+ while not completed_rendering:
+ # Catch errors such as {{ object.element }} where
+ # object is not defined
+ try:
+ renderend_content = task.render_template(content, context)
+ completed_rendering = True
+ except Exception as e:
+ undefined_variable = re.sub(" is undefined", "", str(e))
+ undefined_variable = re.sub("'", "", undefined_variable)
+ context[undefined_variable] = dict()
+ message = "Could not find the object '{}'".format(undefined_variable)
+ errors_while_rendering.append(message)
+ return renderend_content, errors_while_rendering
+
+ def _task_level_(self, task):
+ messages = {}
+ task_instance = TaskInstance(task=task, execution_date=timezone.utcnow())
+ context = task_instance.get_template_context()
+ for attr_name in task.template_fields:
+ content = getattr(task, attr_name)
+ if content:
+ rendered_content, errors_while_rendering = self._render_task_content(
+ task, content, context
+ )
+ debug_error_messages = list(
+ self._check_rendered_content(rendered_content)
+ )
+ messages[attr_name] = errors_while_rendering + debug_error_messages
+
+ return messages
+
+ def _dag_level_(self, dag):
+ dag.template_undefined = jinja2.DebugUndefined
+ tasks = dag.tasks
+ messages = {}
+ for task in tasks:
+ error_messages = self._task_level_(task)
+ messages[task.task_id] = error_messages
+ return messages
+
+ def check(self, dagbag=None):
+ if not dagbag:
+ dag_folder = conf.get("core", "dags_folder")
+ dagbag = DagBag(dag_folder)
+ dags = dagbag.dags
+ messages = []
+ for dag_id, dag in dags.items():
+ dag_messages = self._dag_level_(dag)
Review comment:
A bit more thinking on this. We could -
1. Regex search the python files for a pattern where `template_undefined=jinja2.` exists.
2. If a match occurs - search `dag_id="` using regex around the match and get the dag_id
3. The gathered dag_id's then can be skipped for a check.
This approach does omit cases such as -
```
dag_name = "example_dag"
example = DAG(dag_id=dag_name, template_undefined=jinja2.Undefined)
```
How would you suggest writing this?
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