first commit

swingmusic/db/engine.py

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+from contextlib import contextmanager
+
+from sqlalchemy import Engine, create_engine, event
+from sqlalchemy.orm import sessionmaker
+
+from swingmusic.settings import Paths
+
+
+@event.listens_for(Engine, "connect")
+def set_sqlite_pragma(dbapi_connection, connection_record):
+    cursor = dbapi_connection.cursor()
+    cursor.execute("PRAGMA journal_mode=WAL")
+    cursor.execute("PRAGMA synchronous=NORMAL")
+    cursor.execute("PRAGMA cache_size=10000")
+    cursor.execute("PRAGMA foreign_keys=ON")
+    cursor.execute("PRAGMA temp_store=FILE")
+    cursor.execute("PRAGMA mmap_size=0")
+    cursor.close()
+
+
+class classproperty(property):
+    """
+    A class property decorator.
+    """
+
+    def __get__(self, owner_self, owner_cls):
+        if self.fget:
+            return self.fget(owner_cls)
+
+
+class DbEngine:
+    """
+    The database engine instance.
+    """
+
+    _engine: Engine | None = None
+
+    @classproperty
+    def engine(cls) -> Engine:
+        if not cls._engine:
+            cls._engine = create_engine(
+                f"sqlite+pysqlite:///{Paths().app_db_path}",
+                echo=False,
+                max_overflow=20,
+                pool_size=10,
+            )
+
+        return cls._engine
+
+    @classmethod
+    @contextmanager
+    def manager(cls, commit: bool = False):
+        """
+        This context manager manages access to the database.
+
+        When the context manager is entered, it returns a session object that can be used to execute SQL statements.
+
+        If the `commit` parameter is set to `True`, the context manager will commit the transaction when it exits.
+        """
+        Session = sessionmaker(cls.engine)
+
+        try:
+            with Session() as session:
+                yield session
+
+                if commit:
+                    session.commit()
+                # yield session.execution_options(preserve_rowcount=True, yield_per=100)
+            # yield conn.execution_options(preserve_rowcount=True, yield_per=100)
+        except Exception as e:
+            session.rollback()
+            raise e
+        finally:
+            if commit:
+                session.commit()
+
+            session.close()
+            # del conn
+            # cls.engine.clear_compiled_cache()