Adding ChainBetwenDAGAndOperatorNotAllowedRule for easing upgrade to …

…2.0 (#11839)

* Adding ChainBetwenDAGAndOperatorNotAllowedRule for checking upgrade to Airflow 2.0 (#11040)

* Cleaning up tests for #11839

airflow/upgrade/rules/chain_between_dag_and_operator_not_allowed_rule.py

@@ -0,0 +1,73 @@
+# 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
+
+from airflow import conf
+from airflow.upgrade.rules.base_rule import BaseRule
+from airflow.utils.dag_processing import list_py_file_paths
+
+
+class ChainBetweenDAGAndOperatorNotAllowedRule(BaseRule):
+
+    title = "Chain between DAG and operator not allowed."
+
+    description = "Assigning task to a DAG using bitwise shift (bit-shift) operators are no longer supported."
+
+    def _change_info(self, file_path, line_number):
+        return "{} Affected file: {} (line {})".format(
+            self.title, file_path, line_number
+        )
+
+    def _check_file(self, file_path):
+        problems = []
+        with open(file_path, "r") as file_pointer:
+            lines = file_pointer.readlines()
+            python_space = r"\s*\\?\s*\n?\s*"
+            # Find all the dag variable names.
+            dag_vars = re.findall(r"([A-Za-z0-9_]+){}={}DAG\(".format(python_space, python_space),
+                                  "".join(lines))
+            history = ""
+            for line_number, line in enumerate(lines, 1):
+                # Someone could have put the bitshift operator on a different line than the dag they
+                # were using it on, so search for dag >> or << dag in all previous lines that did
+                # not contain a logged issue.
+                history += line
+                matches = [
+                    re.search(r"DAG\([^\)]+\){}>>".format(python_space), history),
+                    re.search(r"<<{}DAG\(".format(python_space), history)
+                ]
+                for dag_var in dag_vars:
+                    matches.extend([
+                        re.search(r"(\s|^){}{}>>".format(dag_var, python_space), history),
+                        re.search(r"<<\s*{}{}".format(python_space, dag_var), history),
+                    ])
+                if any(matches):
+                    problems.append(self._change_info(file_path, line_number))
+                    # If we found a problem, clear our history so we don't re-log the problem
+                    # on the next line.
+                    history = ""
+        return problems
+
+    def check(self):
+        dag_folder = conf.get("core", "dags_folder")
+        file_paths = list_py_file_paths(directory=dag_folder, include_examples=False)
+        problems = []
+        for file_path in file_paths:
+            problems.extend(self._check_file(file_path))
+        return problems

tests/upgrade/rules/test_chain_between_dag_and_operator_not_allowed_rule.py

@@ -0,0 +1,112 @@
+# 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 contextlib import contextmanager
+from unittest import TestCase
+
+from tempfile import NamedTemporaryFile
+from tests.compat import mock
+
+from airflow.upgrade.rules.chain_between_dag_and_operator_not_allowed_rule import \
+    ChainBetweenDAGAndOperatorNotAllowedRule
+
+
+@contextmanager
+def create_temp_file(mock_list_files, lines):
+    with NamedTemporaryFile("w+") as temp_file:
+        mock_list_files.return_value = [temp_file.name]
+        temp_file.writelines("\n".join(lines))
+        temp_file.flush()
+        yield temp_file
+
+
+@mock.patch("airflow.upgrade.rules.chain_between_dag_and_operator_not_allowed_rule.list_py_file_paths")
+class TestChainBetweenDAGAndOperatorNotAllowedRule(TestCase):
+    msg_template = "{} Affected file: {} (line {})"
+
+    def test_rule_metadata(self, _):
+        rule = ChainBetweenDAGAndOperatorNotAllowedRule()
+        assert isinstance(rule.description, str)
+        assert isinstance(rule.title, str)
+
+    def test_valid_check(self, mock_list_files):
+        lines = ["with DAG('my_dag') as dag:",
+                 "    dummy1 = DummyOperator(task_id='dummy1')",
+                 "    dummy2 = DummyOperator(task_id='dummy2')",
+                 "    dummy1 >> dummy2"]
+
+        with create_temp_file(mock_list_files, lines):
+            rule = ChainBetweenDAGAndOperatorNotAllowedRule()
+            msgs = rule.check()
+            assert 0 == len(msgs)
+
+    def test_invalid_check(self, mock_list_files):
+        lines = ["my_dag1 = DAG('my_dag')",
+                 "dummy = DummyOperator(task_id='dummy')",
+                 "my_dag1 >> dummy"]
+
+        with create_temp_file(mock_list_files, lines) as temp_file:
+            rule = ChainBetweenDAGAndOperatorNotAllowedRule()
+            msgs = rule.check()
+            expected_messages = [self.msg_template.format(rule.title, temp_file.name, 3)]
+            assert expected_messages == msgs
+
+    def test_invalid_check_no_var_rshift(self, mock_list_files):
+        lines = ["DAG('my_dag') >> DummyOperator(task_id='dummy')"]
+
+        with create_temp_file(mock_list_files, lines) as temp_file:
+            rule = ChainBetweenDAGAndOperatorNotAllowedRule()
+            msgs = rule.check()
+            expected_messages = [self.msg_template.format(rule.title, temp_file.name, 1)]
+            assert expected_messages == msgs
+
+    def test_invalid_check_no_var_lshift(self, mock_list_files):
+        lines = ["DummyOperator(",
+                 "task_id='dummy') << DAG('my_dag')"]
+
+        with create_temp_file(mock_list_files, lines) as temp_file:
+            rule = ChainBetweenDAGAndOperatorNotAllowedRule()
+            msgs = rule.check()
+            expected_messages = [self.msg_template.format(rule.title, temp_file.name, 2)]
+            assert expected_messages == msgs
+
+    def test_invalid_check_multiline(self, mock_list_files):
+        lines = ["dag = \\",
+                 "    DAG('my_dag')",
+                 "dummy = DummyOperator(task_id='dummy')",
+                 "",
+                 "dag >> \\",
+                 "dummy"]
+
+        with create_temp_file(mock_list_files, lines) as temp_file:
+            rule = ChainBetweenDAGAndOperatorNotAllowedRule()
+            msgs = rule.check()
+            expected_messages = [self.msg_template.format(rule.title, temp_file.name, 5)]
+            assert expected_messages == msgs
+
+    def test_invalid_check_multiline_lshift(self, mock_list_files):
+        lines = ["dag = \\",
+                 "    DAG('my_dag')",
+                 "dummy = DummyOperator(task_id='dummy')",
+                 "",
+                 "dummy << \\",
+                 "dag"]
+
+        with create_temp_file(mock_list_files, lines) as temp_file:
+            rule = ChainBetweenDAGAndOperatorNotAllowedRule()
+            msgs = rule.check()
+            expected_messages = [self.msg_template.format(rule.title, temp_file.name, 6)]
+            assert expected_messages == msgs