prevent circular imports

media_manager/database/__init__.py

@@ -1,44 +1,82 @@
+# media_manager/database/__init__.py
 import logging
+import os
 from contextvars import ContextVar
-from typing import Annotated, Any, Generator
+from typing import Annotated, Any, Generator, Optional
 
 from fastapi import Depends
 from sqlalchemy import create_engine
+from sqlalchemy.engine import Engine
 from sqlalchemy.orm import Session, declarative_base, sessionmaker
 
-from media_manager.config import AllEncompassingConfig
-
 log = logging.getLogger(__name__)
-config = AllEncompassingConfig().database
 
-db_url = (
-    "postgresql+psycopg"
-    + "://"
-    + config.user
-    + ":"
-    + config.password
-    + "@"
-    + config.host
-    + ":"
-    + str(config.port)
-    + "/"
-    + config.dbname
-)
-
-engine = create_engine(
-    db_url,
-    echo=False,
-    pool_size=10,
-    max_overflow=10,
-    pool_timeout=30,
-    pool_recycle=1800,
-)
-log.debug("initializing sqlalchemy declarative base")
 Base = declarative_base()
-SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+engine: Optional[Engine] = None
+SessionLocal: Optional[sessionmaker] = None
+
+
+def build_db_url(
+    user: str,
+    password: str,
+    host: str,
+    port: int | str,
+    dbname: str,
+) -> str:
+    return f"postgresql+psycopg://{user}:{password}@{host}:{port}/{dbname}"
+
+
+def init_engine(
+    db_config: Any | None = None,
+    url: str | None = None,
+) -> Engine:
+    """
+    Initialize the global SQLAlchemy engine and session factory.
+    Pass either a DbConfig-like object or a full URL. Only initializes once.
+    """
+    global engine, SessionLocal
+    if engine is not None:
+        return engine
+
+    if url is None:
+        if db_config is None:
+            url = os.getenv("DATABASE_URL")
+            if not url:
+                raise RuntimeError("DB config or `DATABASE_URL` must be provided")
+        else:
+            url = build_db_url(
+                db_config.user,
+                db_config.password,
+                db_config.host,
+                db_config.port,
+                db_config.dbname,
+            )
+
+    engine = create_engine(
+        url,
+        echo=False,
+        pool_size=10,
+        max_overflow=10,
+        pool_timeout=30,
+        pool_recycle=1800,
+    )
+    SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+    log.debug("SQLAlchemy engine initialized")
+    return engine
+
+
+def get_engine() -> Engine:
+    if engine is None:
+        raise RuntimeError("Engine not initialized. Call init_engine(...) first.")
+    return engine
 
 
 def get_session() -> Generator[Session, Any, None]:
+    if SessionLocal is None:
+        raise RuntimeError(
+            "Session factory not initialized. Call init_engine(...) first."
+        )
     db = SessionLocal()
     try:
         yield db
@@ -46,12 +84,10 @@ def get_session() -> Generator[Session, Any, None]:
     except Exception as e:
         db.rollback()
         log.critical(f"error occurred: {e}")
-        raise e
+        raise
     finally:
         db.close()
 
 
 db_session: ContextVar[Session] = ContextVar("db_session")
-
-
 DbSessionDependency = Annotated[Session, Depends(get_session)]