Implemented connection pool-based DatabaseManager; Implement _get_cursor() contextmanager; Added system files

Author: prawn-cake

.bumpversion.cfg

@@ -0,0 +1,10 @@
+[bumpversion]
+current_version = 0.1.0
+tag = True
+tag_name = {new_version}
+commit = True
+
+[bumpversion:file:setup.py]
+
+[bumpversion:file:pgclient/__init__.py]
+

Makefile

@@ -0,0 +1,36 @@
+# System variables
+ENV_DIR=$(CURDIR)/.env
+PYTHON=$(ENV_DIR)/bin/python
+COVERAGE=$(ENV_DIR)/bin/coverage
+PROJECT_NAME=pgclient
+
+help:
+# target: help - Display callable targets
+	@grep -e "^# target:" [Mm]akefile | sed -e 's/^# target: //g'
+
+.PHONY: env
+env:
+# target: env - create virtualenv and install packages
+	@virtualenv $(ENV_DIR)
+	@$(ENV_DIR)/bin/pip install -r $(CURDIR)/requirements.txt
+
+.PHONY: pypi_upload
+pypi_upload:
+# target: pypi_upload - Upload package to pypi.python.org
+	@$(PYTHON) setup.py sdist upload
+
+.PHONY: test
+test: env
+# target: test - Run tests
+	@$(PYTHON) -m unittest discover
+	
+
+.PHONY: test_ci
+test_ci: env
+# target: test_ci - Run tests command adapt for CI systems
+	@$(PYTHON) -m unittest discover
+
+.PHONY: test_coverage
+# target: test_coverage - Run tests with coverage
+test_coverage: env
+	@$(COVERAGE) run --source=$(PROJECT_NAME) $(PYTHON) -m unittest discover

README.md

@@ -0,0 +1,40 @@
+pgclient
+=============
+
+pgclient - yet another pool-based psycopg2 wrapper. 
+
+
+Quick start
+===========
+
+
+
+
+Installation
+============
+System dependencies
+-------------------
+
+Install the following dependencies via `.deb` or `.rpm` packages
+
+* python-dev
+* libpq-dev
+
+Install package
+---------------
+
+    pip install pgclient
+
+
+Bug tracker
+===========
+
+Warm welcome to suggestions and concerns
+
+https://github.com/prawn-cake/pgclient/issues
+
+
+License
+=======
+
+MIT - http://opensource.org/licenses/MIT

pgclient/__init__.py

@@ -1,5 +1,3 @@
 # -*- coding: utf-8 -*-
 
-
-if __name__ == '__main__':
-    pass
+__version__ = '0.1.0'

pgclient/client.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 import psycopg2
+import psycopg2.pool as pgpool
 import psycopg2.extras as pg_extras
 import abc
 import six
@@ -11,51 +12,51 @@
 
 
 class DatabaseManager(object):
-    def __init__(self, dsn, pool_size=1):
+    def __init__(self, dsn=None, database=None, user=None, password=None,
+                 host=None, port=None, pool_size=1):
         self.dsn = dsn
-        self._conn = None
-        self.pool_size = pool_size
+
+        # Pass connection params as is
+        conn_params = dict(dsn=dsn, database=database, user=user,
+                           password=password, host=host, port=port)
+        if pool_size < 1:
+            raise ValueError('Wrong pool_size value. Must be >= 1. '
+                             'Current: {}'.format(pool_size))
+        # Init thread-safe connection pool
+        self.pool = pgpool.ThreadedConnectionPool(
+            minconn=1, maxconn=pool_size, **conn_params)
 
     @property
     def connection(self):
         """Lazy connection property
 
         :return: postgresql connection instance
         """
-        if self._conn is None:
-            self._conn = self._get_connection()
-        return self._conn
+        return self.pool.getconn()
 
+    @contextmanager
+    def _get_cursor(self, cursor_factory=None):
+        conn = self.connection
+        try:
+            yield conn.cursor(cursor_factory=cursor_factory)
+            conn.commit()
+        except psycopg2.DatabaseError as err:
+            conn.rollback()
+            raise psycopg2.DatabaseError(err)
+        finally:
+            self.pool.putconn(conn)
+
+    # TODO: rename it
     @property
     def cursor(self):
-        return self.connection.cursor()
+        return self._get_cursor()
 
     @property
     def dict_cursor(self):
         """Return dict cursor. It enables accessing via column names instead
         of indexes
         """
-        return self.connection.cursor(cursor_factory=pg_extras.DictCursor)
-
-    def _get_connection(self):
-        return psycopg2.connect(dsn=self.dsn)
-
-    @contextmanager
-    def get_transaction_cursor(self):
-        """Public transaction context manager. Useful for getting transactional
-         cursor to be able execute several SQL requests in one transaction
-
-        Example:
-            with db_manager.get_transaction_cursor() as t_cursor:
-                t_cursor.execute('SELECT * FROM ...')
-                t_cursor.execute('INSERT INTO my_table VALUES ...')
-
-        So, the code above will be executed within one transaction
-
-        """
-        with self.connection as conn:
-            with conn.cursor() as t_cursor:
-                yield t_cursor
+        return self._get_cursor(cursor_factory=pg_extras.DictCursor)
 
 
 @six.add_metaclass(abc.ABCMeta)

pgclient/tests.py

@@ -1,22 +1,25 @@
 # -*- coding: utf-8 -*-
 import unittest
+from pgclient.client import DatabaseManager
 
 
 class DatabaseManagerTest(unittest.TestCase):
     def setUp(self):
-        pass
+        self.db_manager = DatabaseManager(dsn='localhost')
 
     def tearDown(self):
         pass
 
     def test_connection(self):
-        pass
+        conn = self.db_manager.connection
+        self.assertTrue(conn)
 
     def test_cursor(self):
-        pass
+        with self.db_manager.cursor as cursor:
+            result = cursor.execute('SELECT * FROM').fetchall()
+        self.assertTrue(result)
 
     def test_dict_cursor(self):
-        pass
-
-    def test_get_transaction_cursor_context_manager(self):
-        pass
+        with self.db_manager.dict_cursor as cursor:
+            result = cursor.execute('SELECT * FROM').fetchall()
+        self.assertTrue(result)

requirements.txt

@@ -1,2 +1,9 @@
 psycopg2==2.6.1
-six
+
+# Python 2 to 3 compatibility
+six==1.9.0
+
+# System packages
+coverage==3.7.1
+bumpversion==0.5.3
+mock

setup.py

@@ -0,0 +1,12 @@
+from distutils.core import setup
+
+setup(
+    name='pgclient',
+    version='0.1.0',
+    packages=['pgclient'],
+    url='https://github.com/prawn-cake/pgclient',
+    license='MIT',
+    author='Maksim Ekimovskii',
+    author_email='[email protected]',
+    description='Yet another psycopg2 wrapper'
+)