[GitHub] [airflow] vamega commented on a change in pull request #6850: [AIRFLOW-6296] add ODBC hook & deprecation warning for pymssql

[GitBox <gi...@apache.org>]

vamega commented on a change in pull request #6850: [AIRFLOW-6296] add ODBC hook & deprecation warning for pymssql
URL: https://github.com/apache/airflow/pull/6850#discussion_r367022367
 
 

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 File path: airflow/providers/odbc/hooks/odbc.py
 ##########
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+# 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.
+"""
+This module contains ODBC hook.
+"""
+from typing import Optional
+from urllib.parse import quote_plus
+
+import pyodbc
+
+from airflow.hooks.dbapi_hook import DbApiHook
+from airflow.utils.helpers import merge_dicts
+
+
+class OdbcHook(DbApiHook):
+    """
+    Interact with odbc data sources using pyodbc.
+
+    See :ref:`howto/connection/odbc` for full documentation.
+    """
+
+    DEFAULT_SQLALCHEMY_SCHEME = 'mssql+pyodbc'
+    conn_name_attr = 'odbc_conn_id'
+    default_conn_name = 'odbc_default'
+    supports_autocommit = True
+
+    def __init__(
+        self,
+        *args,
+        database: Optional[str] = None,
+        driver: Optional[str] = None,
+        dsn: Optional[str] = None,
+        connect_kwargs: Optional[dict] = None,
+        sqlalchemy_scheme: Optional[str] = None,
+        **kwargs,
+    ):
+        """
+        :param args: passed to DbApiHook
+        :param database: database to use -- overrides connection ``schema``
+        :param driver: name of driver or path to driver. overrides driver supplied in connection ``extra``
+        :param dsn: name of DSN to use.  overrides DSN supplied in connection ``extra``
+        :param connect_kwargs: keyword arguments passed to ``pyodbc.connect``
+        :param sqlalchemy_scheme: Scheme sqlalchemy connection.  Default is ``mssql+pyodbc`` Only used for
+          ``get_sqlalchemy_engine`` and ``get_sqlalchemy_connection`` methods.
+        :param kwargs: passed to DbApiHook
+        """
+        super().__init__(*args, **kwargs)
+        self._database = database
+        self._driver = driver
+        self._dsn = dsn
+        self._conn_str = None
+        self._sqlalchemy_scheme = sqlalchemy_scheme
+        self._connection = None
+        self._connect_kwargs = connect_kwargs
+
+    @property
+    def connection(self):
+        """
+        ``airflow.Connection`` object with connection id ``odbc_conn_id``
+        """
+        if not self._connection:
+            self._connection = self.get_connection(getattr(self, self.conn_name_attr))
+        return self._connection
+
+    @property
+    def database(self):
+        """
+        Database provided in init if exists; otherwise, ``schema`` from ``Connection`` object.
+        """
+        return self._database or self.connection.schema
+
+    @property
+    def sqlalchemy_scheme(self):
+        """
+        Database provided in init if exists; otherwise, ``schema`` from ``Connection`` object.
+        """
+        return (
+            self._sqlalchemy_scheme or
+            self.connection_extra_lower.get('sqlalchemy_scheme') or
+            self.DEFAULT_SQLALCHEMY_SCHEME
+        )
+
+    @property
+    def connection_extra_lower(self):
+        """
+        ``connection.extra_dejson`` but where keys are converted to lower case.
+
+        This is used internally for case-insensitive access of odbc params.
+        """
+        return {k.lower(): v for k, v in self.connection.extra_dejson.items()}
+
+    @property
+    def driver(self):
+        """
+        Driver from init param if given; else try to find one in connection extra.
+        """
+        if not self._driver:
+            driver = self.connection_extra_lower.get('driver')
+            if driver:
+                self._driver = driver
+        return self._driver and self._driver.strip().lstrip('{').rstrip('}').strip()
+
+    @property
+    def dsn(self):
+        """
+        DSN from init param if given; else try to find one in connection extra.
+        """
+        if not self._dsn:
+            dsn = self.connection_extra_lower.get('dsn')
+            if dsn:
+                self._dsn = dsn.strip()
+        return self._dsn
+
+    @property
+    def odbc_connection_string(self):
+        """
+        ODBC connection string
+        We build connection string instead of using ``pyodbc.connect`` params because, for example, there is
+        no param representing ``ApplicationIntent=ReadOnly``.  Any key-value pairs provided in
+        ``Connection.extra`` will be added to the connection string.
+        """
+        if not self._conn_str:
+            conn_str = ''
+            if self.driver:
+                conn_str += f"DRIVER={{{self.driver}}};"
+            if self.dsn:
+                conn_str += f"DSN={self.dsn};"
+            if self.connection.host:
+                conn_str += f"SERVER={self.connection.host};"
+            database = self.database or self.connection.schema
+            if database:
+                conn_str += f"DATABASE={database};"
+            if self.connection.login:
+                conn_str += f"UID={self.connection.login};"
+            if self.connection.password:
+                conn_str += f"PWD={self.connection.password};"
+            if self.connection.port:
+                f"PORT={self.connection.port};"
+
+            extra_exclude = {'driver', 'dsn', 'connect_kwargs', 'sqlalchemy_scheme'}
+            extra_params = {
+                k: v
+                for k, v in self.connection.extra_dejson.items()
+                if not k.lower() in extra_exclude
+            }
+            for k, v in extra_params.items():
+                conn_str += f"{k}={v};"
+
+            self._conn_str = conn_str
+        return self._conn_str
+
+    @property
+    def connect_kwargs(self):
+        """
+        Returns effective kwargs to be passed to ``pyodbc.connect`` after merging between conn extra,
+        ``connect_kwargs`` and hook init.
+
+        Hook ``connect_kwargs`` precedes ``connect_kwargs`` from conn extra.
+
+        String values for 'true' and 'false' are converted to bool type.
+
+        If ``attrs_before`` provided, keys and values are converted to int, as required by pyodbc.
+        """
+
+        def clean_bool(val):  # pylint: disable=inconsistent-return-statements
+            if hasattr(val, 'lower'):
+                if val.lower() == 'true':
+                    return True
+                elif val.lower() == 'false':
+                    return False
+            else:
+                return val
+
+        conn_connect_kwargs = self.connection_extra_lower.get('connect_kwargs', {})
+        hook_connect_kwargs = self._connect_kwargs or {}
+        merged_connect_kwargs = merge_dicts(conn_connect_kwargs, hook_connect_kwargs)
+
+        if 'attrs_before' in merged_connect_kwargs:
+            merged_connect_kwargs['attrs_before'] = {
+                int(k): int(v) for k, v in merged_connect_kwargs['attrs_before'].items()
+            }
+
+        return {k: clean_bool(v) for k, v in merged_connect_kwargs.items()}
+
+    def get_conn(self) -> pyodbc.Connection:
 
 Review comment:
   Also, is this method used anywhere? I can't seem to find usage anywhere?
   
   If not, could you help me understand what you envision this method being used for?

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