From 9f2c9d14d35699ca7e071b0b9079980712ac48e9 Mon Sep 17 00:00:00 2001
From: Tim Van Baak <tim.vanbaak@gmail.com>
Date: Tue, 4 May 2021 23:05:03 -0700
Subject: [PATCH] Refactor db infra to require instantiating object

---
 amanuensis/database.py | 70 ++++++++++++++++++++++--------------------
 1 file changed, 36 insertions(+), 34 deletions(-)

diff --git a/amanuensis/database.py b/amanuensis/database.py
index 98afcaa..74ee911 100644
--- a/amanuensis/database.py
+++ b/amanuensis/database.py
@@ -6,43 +6,31 @@ import sqlite3
 import uuid
 
 
-# Register GUID as a known type with sqlite
-sqlite3.register_converter('GUID', lambda h: uuid.UUID(hex=h))
-sqlite3.register_adapter(uuid.UUID, lambda u: u.hex)
-
 class Uuid(TypeDecorator):
-	"""
-	A uuid backed by a char(32) field in sqlite.
-	"""
-	impl = CHAR(32)
+    """
+    A uuid backed by a char(32) field in sqlite.
+    """
+    impl = CHAR(32)
 
-	def process_bind_param(self, value, dialect):
-		if value is None:
-			return value
-		elif not isinstance(value, uuid.UUID):
-			return f'{uuid.UUID(value).int:32x}'
-		else:
-			return f'{value.int:32x}'
+    def process_bind_param(self, value, dialect):
+        if value is None:
+            return value
+        elif not isinstance(value, uuid.UUID):
+            return f'{uuid.UUID(value).int:32x}'
+        else:
+            return f'{value.int:32x}'
 
-	def process_result_value(self, value, dialect):
-		if value is None:
-			return value
-		elif not isinstance(value, uuid.UUID):
-			return uuid.UUID(value)
-		else:
-			return value
+    def process_result_value(self, value, dialect):
+        if value is None:
+            return value
+        elif not isinstance(value, uuid.UUID):
+            return uuid.UUID(value)
+        else:
+            return value
 
-engine = create_engine('sqlite:///:memory:', connect_args={'detect_types': sqlite3.PARSE_DECLTYPES})
-
-# Enable foreign key constraints
-@event.listens_for(engine, "connect")
-def set_sqlite_pragma(dbapi_connection, connection_record):
-    cursor = dbapi_connection.cursor()
-    cursor.execute("PRAGMA foreign_keys=ON")
-    cursor.close()
 
 # Define naming conventions for generated constraints
-metadata = MetaData(bind=engine, naming_convention={
+metadata = MetaData(naming_convention={
     "ix": "ix_%(column_0_label)s",
     "uq": "uq_%(table_name)s_%(column_0_name)s",
     "ck": "ck_%(table_name)s_%(constraint_name)s",
@@ -50,8 +38,22 @@ metadata = MetaData(bind=engine, naming_convention={
     "pk": "pk_%(table_name)s"
 })
 
-# Thread-safe db session
-session = scoped_session(sessionmaker(bind=engine))
-
 # Base class for ORM models
 ModelBase = declarative_base(metadata=metadata)
+
+
+class DbContext():
+    def __init__(self, db_uri, debug=False):
+        # Create an engine and enable foreign key constraints in sqlite
+        self.engine = create_engine(db_uri, echo=debug)
+        @event.listens_for(self.engine, "connect")
+        def set_sqlite_pragma(dbapi_connection, connection_record):
+            cursor = dbapi_connection.cursor()
+            cursor.execute("PRAGMA foreign_keys=ON")
+            cursor.close()
+
+        # Create a thread-safe session factory
+        self.session = scoped_session(sessionmaker(bind=self.engine))
+
+    def create_all(self):
+        ModelBase.metadata.create_all(self.engine)