refactor: Update database service to use pool_size and max_overflow settings

The DatabaseService class in service.py has been updated to use the pool_size and max_overflow settings from the SettingsService. This change allows for better control over the number of connections in the connection pool and the number of connections that can be opened beyond the pool size. The commit also includes necessary modifications to the create_engine function to pass the pool_size and max_overflow parameters.

Note: The commit message has been generated based on the provided code changes and recent commits.

src/backend/base/langflow/services/database/service.py

@@ -20,12 +20,14 @@ from langflow.services.utils import teardown_superuser
 
 if TYPE_CHECKING:
     from sqlalchemy.engine import Engine
+    from langflow.services.settings.manager import SettingsService
 
 
 class DatabaseService(Service):
     name = "database_service"
 
-    def __init__(self, database_url: str):
+    def __init__(self, database_url: str, settings_service: "SettingsService"):
+        self.settings_service = settings_service
         self.database_url = database_url
         # This file is in langflow.services.database.manager.py
         # the ini is in langflow
@@ -41,7 +43,12 @@ class DatabaseService(Service):
             connect_args = {"check_same_thread": False}
         else:
             connect_args = {}
-        return create_engine(self.database_url, connect_args=connect_args)
+        return create_engine(
+            self.database_url,
+            connect_args=connect_args,
+            pool_size=self.settings_service.settings.pool_size,
+            max_overflow=self.settings_service.settings.max_overflow,
+        )
 
     def __enter__(self):
         self._session = Session(self.engine)

src/backend/base/langflow/services/settings/base.py

@@ -67,6 +67,11 @@ class Settings(BaseSettings):
 
     dev: bool = False
     database_url: Optional[str] = None
+    """Database URL for Langflow. If not provided, Langflow will use a SQLite database."""
+    pool_size: int = 10
+    """The number of connections to keep open in the connection pool. If not provided, the default is 10."""
+    max_overflow: int = 10
+    """The number of connections to allow that can be opened beyond the pool size. If not provided, the default is 10."""
     cache_type: str = "async"
     remove_api_keys: bool = False
     components_path: List[str] = []