How to load a specific catalog dataset instance in kedro 0.17.0? - hook

Question

We were using kedro version 0.15.8 and we were loading one specific item from the catalog this way:
from kedro.context import load_context
get_context().catalog.datasets.__dict__[key]
Now, we are changing to kedro 0.17.0 and trying to load the catalogs datasets the same way(using the framework context):
from kedro.framework.context import load_context
get_context().catalog.datasets.__dict__[key]
And now we get the error:
kedro.framework.context.context.KedroContextError: Expected an instance of ConfigLoader, got NoneType instead.
It's because the hook register_config_loader from the project it's not being used by the hook_manager that calls the function.
The project hooks are the defined the following way:
class ProjectHooks:
#hook_impl
def register_pipelines(self) -> Dict[str, Pipeline]:
"""Register the project's pipeline.
Returns:
A mapping from a pipeline name to a ``Pipeline`` object.
"""
pm = pre_master.create_pipeline()
return {
"pre_master": pm,
"__default__": pm
}
#hook_impl
def register_config_loader(self, conf_paths: Iterable[str]) -> ConfigLoader:
return ConfigLoader(conf_paths)
#hook_impl
def register_catalog(
self,
catalog: Optional[Dict[str, Dict[str, Any]]],
credentials: Dict[str, Dict[str, Any]],
load_versions: Dict[str, str],
save_version: str,
journal: Journal,
) -> DataCatalog:
return DataCatalog.from_config(
catalog, credentials, load_versions, save_version, journal
)
project_hooks = ProjectHooks()
And the settings are called the following way:
"""Project settings."""
from price_based_trading.hooks import ProjectHooks
HOOKS = (ProjectHooks(),)
How can we configure that in a way that the hooks are used calling the method load_context(_working_dir).catalog.datasets ?
I posted the same question in the kedro community: https://discourse.kedro.community/t/how-to-load-a-specific-catalog-item-in-kedro-0-17-0/310

Answer 1

It was a silly mistake because I was not creating the Kedro session. To load an item of the catalog it can be done with the following code:
from kedro.framework.session import get_current_session
from kedro.framework.session import KedroSession
KedroSession.create("name_of_proyect") as session:
key = "item_of_catalog"
session = get_current_session()
context = session.load_context()
kedro_connector = context.catalog.datasets.__dict__[key]
// or kedro_connector = context.catalog._get_datasets(key)