first commit

helix/db/redis_manager.py

@@ -0,0 +1,17 @@
+import json
+
+import redis
+
+
+class RedisManager(object):
+    @staticmethod
+    def get_redis_connection(vcap_env, heroku_redis_url):
+        if vcap_env:
+            redis_env = json.loads(vcap_env)['rediscloud'][0]['credentials']
+            return redis.Redis(host=redis_env['hostname'],
+                               port=int(redis_env['port']),
+                               password=redis_env['password'])
+        elif heroku_redis_url:
+            return redis.Redis.from_url(heroku_redis_url)
+        else:
+            return redis.Redis(host='localhost', port=6379, db=0)

helix/db/sql_manager.py

@@ -0,0 +1,26 @@
+import sqlalchemy
+from sqlalchemy.orm import sessionmaker
+
+
+class SQLManager(object):
+    # Cache the database connection per application process.
+    # More properly, this should be kept in thread-local state (threading.local()), but should suffice.
+    # Each passed connection url will have its own pool.
+    engines = {}
+
+    @classmethod
+    def get_sql_session_maker(cls, heroku_postgres_url, should_echo=False, cache=True):
+        if not cache:
+            return sessionmaker(bind=cls.connect(heroku_postgres_url, should_echo=should_echo))()
+        else:
+            engine = cls.engines.setdefault(heroku_postgres_url,
+                                            cls.connect(heroku_postgres_url, should_echo=should_echo))
+
+            return sessionmaker(bind=engine)()
+
+    @staticmethod
+    def connect(heroku_postgres_url, should_echo=False):
+        if heroku_postgres_url:
+            return sqlalchemy.create_engine(heroku_postgres_url, echo=should_echo)
+        else:
+            return sqlalchemy.create_engine('postgres://pivotal:@localhost/pivotal', echo=True)