Add databackend option in superduper magic method

superduperdb/base/build.py

@@ -68,11 +68,13 @@ def build_compute(cfg):
     return LocalComputeBackend()
 
 
-def build_datalayer(cfg=None, **kwargs) -> Datalayer:
+def build_datalayer(cfg=None, databackend=None, **kwargs) -> Datalayer:
     """
     Build a Datalayer object as per ``db = superduper(db)`` from configuration.
 
     :param cfg: Configuration to use. If None, use ``superduperdb.CFG``.
+    :param databackend: Databacked to use.
+                        If None, use ``superduperdb.CFG.data_backend``.
     """
 
     # Configuration
@@ -87,7 +89,8 @@ def build_datalayer(cfg=None, **kwargs) -> Datalayer:
     # Connect to data backend.
     # ------------------------------
     try:
-        databackend = build(cfg.data_backend, data_backends)
+        if not databackend:
+            databackend = build(cfg.data_backend, data_backends)
         logging.info("Data Client is ready.", databackend.conn)
     except Exception as e:
         # Exit quickly if a connection fails.

superduperdb/base/superduper.py

@@ -105,9 +105,16 @@ def create(cls, item: t.Any, **kwargs) -> t.Any:
         if not isinstance(item, (Database, MockDatabase)):
             raise TypeError(f'Expected Database but got {type(item)}')
 
-        logging.warn('Note: This is only recommended in development mode')
+        logging.warn(
+            'Note: This is only recommended in development mode, since config\
+             still holds `data_backend` with the default value, services \
+             like vector search and cdc cannot be reached due to configuration\
+             mismatch. Services will be configured with a `data_backend` uri using \
+             config file hence this client config and\
+             services config will be different.'
+        )
         databackend = MongoDataBackend(conn=item.client, name=item.name)
-        return build_datalayer(cfg=CFG, data_backend=databackend, **kwargs)
+        return build_datalayer(cfg=CFG, databackend=databackend, **kwargs)
 
 
 class SklearnTyper(_DuckTyper):