Add support for Snowflake Key Pair Authentication

This PR adds support for Snowflake Key Pair Authentication.

Unit tests verify everything's getting passed through correctly.

plugins/snowflake/dbt/adapters/snowflake/connections.py

@@ -7,6 +7,8 @@
 
 import dbt.compat
 import dbt.exceptions
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import serialization
 from dbt.adapters.base import Credentials
 from dbt.adapters.sql import SQLConnectionManager
 from dbt.logger import GLOBAL_LOGGER as logger
@@ -29,6 +31,12 @@
             'type': 'string',
             'description': "Either 'externalbrowser', or a valid Okta url"
         },
+        'private_key_path': {
+            'type': 'string',
+        },
+        'private_key_passphrase': {
+            'type': 'string',
+        },
         'database': {
             'type': 'string',
         },
@@ -104,6 +112,11 @@ def open(cls, connection):
             auth_args = {auth_key: credentials[auth_key]
                          for auth_key in ['user', 'password', 'authenticator']
                          if auth_key in credentials}
+
+            auth_args['private_key'] = cls._get_private_key(
+                credentials.get('private_key_path'),
+                credentials.get('private_key_passphrase'))
+
             handle = snowflake.connector.connect(
                 account=credentials.account,
                 database=credentials.database,
@@ -163,6 +176,23 @@ def _split_queries(cls, sql):
         split_query = snowflake.connector.util_text.split_statements(sql_buf)
         return [part[0] for part in split_query]
 
+    @classmethod
+    def _get_private_key(cls, private_key_path, private_key_passphrase):
+        """Get Snowflake private key by path or None."""
+        if private_key_path is None or private_key_passphrase is None:
+            return None
+
+        with open(private_key_path, 'rb') as key:
+            p_key = serialization.load_pem_private_key(
+                key.read(),
+                password=private_key_passphrase.encode(),
+                backend=default_backend())
+
+        return p_key.private_bytes(
+            encoding=serialization.Encoding.DER,
+            format=serialization.PrivateFormat.PKCS8,
+            encryption_algorithm=serialization.NoEncryption())
+
     def add_query(self, sql, model_name=None, auto_begin=True,
                   bindings=None, abridge_sql_log=False):
 

test/unit/test_snowflake_adapter.py

@@ -1,3 +1,5 @@
+from mock import patch
+
 import mock
 import unittest
 
@@ -150,7 +152,7 @@ def test_client_session_keep_alive_false_by_default(self):
                 account='test_account', autocommit=False,
                 client_session_keep_alive=False, database='test_databse',
                 role=None, schema='public', user='test_user',
-                warehouse='test_warehouse')
+                warehouse='test_warehouse', private_key=None)
         ])
 
     def test_client_session_keep_alive_true(self):
@@ -164,7 +166,7 @@ def test_client_session_keep_alive_true(self):
                 account='test_account', autocommit=False,
                 client_session_keep_alive=True, database='test_databse',
                 role=None, schema='public', user='test_user',
-                warehouse='test_warehouse')
+                warehouse='test_warehouse', private_key=None)
         ])
 
     def test_user_pass_authentication(self):
@@ -178,7 +180,7 @@ def test_user_pass_authentication(self):
                 account='test_account', autocommit=False,
                 client_session_keep_alive=False, database='test_databse',
                 password='test_password', role=None, schema='public',
-                user='test_user', warehouse='test_warehouse')
+                user='test_user', warehouse='test_warehouse', private_key=None)
         ])
 
     def test_authenticator_user_pass_authentication(self):
@@ -193,7 +195,7 @@ def test_authenticator_user_pass_authentication(self):
                 client_session_keep_alive=False, database='test_databse',
                 password='test_password', role=None, schema='public',
                 user='test_user', warehouse='test_warehouse',
-                authenticator='test_sso_url')
+                authenticator='test_sso_url', private_key=None)
         ])
 
     def test_authenticator_externalbrowser_authentication(self):
@@ -207,5 +209,23 @@ def test_authenticator_externalbrowser_authentication(self):
                 account='test_account', autocommit=False,
                 client_session_keep_alive=False, database='test_databse',
                 role=None, schema='public', user='test_user',
-                warehouse='test_warehouse', authenticator='externalbrowser')
+                warehouse='test_warehouse', authenticator='externalbrowser',
+                private_key=None)
+        ])
+
+    @patch('dbt.adapters.snowflake.SnowflakeConnectionManager._get_private_key', return_value='test_key')
+    def test_authenticator_private_key_authentication(self, mock_get_private_key):
+        self.config.credentials = self.config.credentials.incorporate(
+            private_key_path='/tmp/test_key.p8',
+            private_key_passphrase='p@ssphr@se')
+
+        self.adapter = SnowflakeAdapter(self.config)
+        self.adapter.connections.get(name='new_connection_with_new_config')
+
+        self.snowflake.assert_has_calls([
+            mock.call(
+                account='test_account', autocommit=False,
+                client_session_keep_alive=False, database='test_database',
+                role=None, schema='public', user='test_user',
+                warehouse='test_warehouse', private_key='test_key')
         ])