From ddbaa811c0c29835d45b6aa39d708d5b830ac14f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Piotr=20Ma=C5=9Blanka?= <piotr.maslanka@henrietta.com.pl>
Date: Sat, 28 May 2022 20:50:55 +0200
Subject: [PATCH] added transaction idiom
---
CHANGELOG.md | 11 +++--------
docs/db.rst | 9 +++++++++
docs/index.rst | 1 +
satella/__init__.py | 2 +-
satella/db.py | 48 +++++++++++++++++++++++++++++++++++++++++++++
tests/test_db.py | 40 +++++++++++++++++++++++++++++++++++++
6 files changed, 102 insertions(+), 9 deletions(-)
create mode 100644 docs/db.rst
create mode 100644 satella/db.py
create mode 100644 tests/test_db.py
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c87dc97a..bc4504eb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,9 +1,4 @@
-# v2.19.0
+# v2.19.2
+
+* added `db_call`
-* unit tests migrated to CircleCI
-* added __len__ to FutureCollection
-* fixed a bug in DictionaryEQAble
-* fixed a bug in ListDeleter
-* minor breaking change: changed semantics of ListDeleter
-* added `CPManager`
-* added `SetZip`
\ No newline at end of file
diff --git a/docs/db.rst b/docs/db.rst
new file mode 100644
index 00000000..2df2fcb7
--- /dev/null
+++ b/docs/db.rst
@@ -0,0 +1,9 @@
+Python DB API 2
+===============
+
+However imperfect may it be, it's here to stay.
+
+So enjoy!
+
+.. autoclass:: satella.db.transaction
+ :members:
diff --git a/docs/index.rst b/docs/index.rst
index 601fa559..d8d58cad 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -28,6 +28,7 @@ Visit the project's page at GitHub_!
instrumentation/metrics
exception_handling
dao
+ db
json
posix
import
diff --git a/satella/__init__.py b/satella/__init__.py
index 6d2db50c..a910817d 100644
--- a/satella/__init__.py
+++ b/satella/__init__.py
@@ -1 +1 @@
-__version__ = '2.19.0'
+__version__ = '2.20.0'
diff --git a/satella/db.py b/satella/db.py
new file mode 100644
index 00000000..1d3ad8ef
--- /dev/null
+++ b/satella/db.py
@@ -0,0 +1,48 @@
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class transaction:
+ """
+ A context manager for wrapping a transaction and getting a cursor from the Python DB API 2.
+
+ Use it as a context manager. commit and rollback will be automatically called for you.
+
+ Use like:
+
+ >>> with transaction(conn) as cur:
+ >>> cur.execute('DROP DATABASE')
+
+ Leaving the context manager will automatically close the cursor for you.
+
+ :param connection: the connection object to use
+ :param close_the_connection_after: whether the connection should be closed after use, False by default
+ :param log_exception: whether to log an exception if it happens
+ """
+ def __init__(self, connection, close_the_connection_after: bool = False,
+ log_exception: bool = True):
+ self.connection = connection
+ self.close_the_connection_after = close_the_connection_after
+ self.cursor = None
+ self.log_exception = log_exception
+
+ def __enter__(self):
+ self.cursor = self.connection.cursor()
+ return self.cursor()
+
+ def __exit__(self, exc_type, exc_val, exc_tb):
+ if exc_val is None:
+ self.connection.commit()
+ else:
+ self.connection.rollback()
+
+ if self.log_exception:
+ logger.error('Exception occurred of type %s', exc_type, exc_info=exc_val)
+
+ self.cursor.close()
+
+ if self.close_the_connection_after:
+ self.connection.close()
+
+ return False
diff --git a/tests/test_db.py b/tests/test_db.py
new file mode 100644
index 00000000..c5d86b02
--- /dev/null
+++ b/tests/test_db.py
@@ -0,0 +1,40 @@
+import unittest
+from unittest.mock import Mock
+
+from satella.db import transaction
+
+
+class TestDB(unittest.TestCase):
+ def test_something(self):
+ class RealConnection:
+ def __init__(self):
+ self.cursor_called = 0
+ self.commit_called = 0
+ self.rollback_called = 0
+ self.close_called = 0
+
+ def cursor(self):
+ self.cursor_called += 1
+ return Mock()
+
+ def commit(self):
+ self.commit_called += 1
+
+ def rollback(self):
+ self.rollback_called += 1
+
+ def close(self):
+ self.close_called += 1
+
+ conn = RealConnection()
+ a = transaction(conn)
+ with a as cur:
+ self.assertEqual(conn.cursor_called, 1)
+ cur.execute('TEST')
+ self.assertEqual(conn.commit_called, 1)
+ try:
+ with a as cur:
+ raise ValueError()
+ except ValueError:
+ self.assertEqual(conn.commit_called, 1)
+ self.assertEqual(conn.rollback_called, 1)
--
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