[GitHub] [airflow] mik-laj commented on a change in pull request #6376: [WIP] [AIRFLOW-5705] Add creds backend classes including AWS SSM

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mik-laj commented on a change in pull request #6376: [WIP] [AIRFLOW-5705] Add creds backend classes including AWS SSM
URL: https://github.com/apache/airflow/pull/6376#discussion_r336801495
 
 

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 File path: airflow/creds.py
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 @@ -0,0 +1,171 @@
+# 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.
+"""
+Classes for obtaining creds in order to produce connection objects.
+"""
+import os
+from abc import ABC, abstractmethod
+from typing import List
+
+import boto3
+
+from airflow.configuration import DEFAULT_CONFIG, AirflowConfigParser, parameterized_config
+from airflow.hooks.base_hook import CONN_ENV_PREFIX
+from airflow.models import Connection
+from airflow.utils.db import provide_session
+
+conf = AirflowConfigParser(default_config=parameterized_config(DEFAULT_CONFIG))
+
+
+class BaseCredsBackend(ABC):
+    """
+    Abstract base class to provide connection objects given a conn_id
+    """
+
+    @abstractmethod
+    def get_connections(self, conn_id) -> List[Connection]:
+        """
+        Get list of connection objects
+
+        :param conn_id:
+        :return:
+        """
+
+
+class EnvCredsBackend(BaseCredsBackend):
+    """
+    Retrieves Connection object from environment variable.
+    """
+
+    # pylint: disable=missing-docstring
+    def get_connections(self, conn_id) -> List[Connection]:
+        environment_uri = os.environ.get(CONN_ENV_PREFIX + conn_id.upper())
+        conn = Connection(conn_id=conn_id, uri=environment_uri)
+        return [conn]
+
+
+class MetastoreCredsBackend(BaseCredsBackend):
+    """
+    Retrieves Connection object from airflow metastore database.
+    """
+
+    # pylint: disable=missing-docstring
+    @provide_session
+    def get_connections(self, conn_id, session=None) -> List[Connection]:
+        conn_list = (
+            session.query(Connection).filter(Connection.conn_id == conn_id).all()
+        )
+        session.expunge_all()
+        return conn_list
+
+
+class AwsSsmCredsBackend(BaseCredsBackend):
+    """
+    Retrieves Connection object from AWS SSM Parameter Store
+
+    Configurable via airflow config like so:
+
+    .. code-block:: ini
+
+        [aws_ssm_creds]
+        ssm_prefix = /airflow
+        profile_name = default
+
+    For example, if ssm path is ``/airflow/AIRFLOW_CONN_SMTP_DEFAULT``, this would be accessible if you
+    provide ``ssm_prefix = /airflow`` and conn_id ``smtp_default``.
+
+    """
+
+    conf_section = "aws_ssm_creds"
+    conf_key_ssm_prefix = "ssm_prefix"
+    default_prefix = "/airflow"
+    conf_key_profile_name = "profile_name"
+    default_profile = "default"
+
+    def __init__(self, *args, **kwargs):
+        pass
+
+    @property
+    def ssm_prefix(self) -> str:
+        """
+        Gets ssm prefix from conf.
+
+        Ensures that there is no trailing slash.
+
+        :return:
+        """
+        ssm_prefix = conf.get(
+            section=self.conf_section,
+            key=self.conf_key_ssm_prefix,
+            fallback=self.default_prefix,
+        )
+        if ssm_prefix[-1] == "/":
+            ssm_prefix = ssm_prefix[:-1]
+        return ssm_prefix
+
+    @property
+    def aws_profile_name(self) -> str:
+        """
+        Gets AWS profile to use from conf.
+
+        :return:
+        """
+        profile_name = conf.get(
+            section=self.conf_section,
+            key=self.conf_key_profile_name,
+            fallback=self.default_profile,
+        )
+        return profile_name
+
+    def build_ssm_path(self, conn_id: str):
+        """
+        Given conn_id, build SSM path.
+
+        Assumes connection params use same naming convention as env vars, but may have arbitrary prefix.
+
+        :param conn_id:
+        :return:
+        """
+        param_name = (CONN_ENV_PREFIX + conn_id).upper()
+        param_path = self.ssm_prefix + "/" + param_name
+        return param_path
+
+    def get_conn_uri(self, conn_id):
+        """
+        Get param value
+
+        :param conn_id:
+        :return:
+        """
+        session = boto3.Session(profile_name=self.aws_profile_name)
+        client = session.client("ssm")
+        response = client.get_parameter(
+            Name=self.build_ssm_path(conn_id=conn_id), WithDecryption=True
+        )
+        value = response["Parameter"]["Value"]
+        return value
+
+    def get_connections(self, conn_id) -> List[Connection]:
+        """
+        Create connection object.
+
+        :param conn_id:
+        :return:
+        """
+        conn_uri = self.get_conn_uri(conn_id=conn_id)
 
 Review comment:
   Storing connections in a URL is probably not the best idea. URL support is related to a long history of errors that I solved. Maybe it is better to serialize the object to another format, e.g. JSON?

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