Configuration

Note: This documentation is based on Kedro 0.14.0, if you spot anything that is incorrect then please create an issue or pull request.

This section contains detailed information about configuration. You may also want to consult the relevant API documentation on kedro.config.

Local and base configuration

We recommend that you keep all configuration files in the conf directory of a Kedro project. However, if you prefer, you may point Kedro to any other directory and change the configuration paths by modifying the CONF_ROOT variable in src/run.py.

Loading

Kedro-specific configuration (e.g., DataCatalog configuration for IO) is loaded using the ConfigLoader class:

from kedro.config import ConfigLoader

conf_paths = ['conf/base', 'conf/local']
conf_loader = ConfigLoader(conf_paths)
conf_catalog = conf_loader.get('catalog*', 'catalog*/**')

This will recursively scan for configuration files firstly in conf/base/ and then in conf/local/ directory according to the following rules:

  • ANY of the following is true:
    • filename starts with catalog OR
    • file is located in a sub-directory whose name is prefixed with catalog
  • AND file extension is one of the following: yaml, yml, json, ini, pickle, xml, properties or shellvars

Configuration information from files stored in base or local that match these rules is merged at runtime and returned in the form of a config dictionary:

  • If any 2 configuration files located inside the same environment path (conf/base/ or conf/local/ in this example) contain the same top-level key, load_config will raise a ValueError indicating that the duplicates are not allowed.
Note: Any top-level keys that start with _ character are considered hidden (or reserved) and therefore are ignored right after the config load. Those keys will neither trigger a key duplication error mentioned above, nor will they appear in the resulting configuration dictionary. However, you may still use such keys for various purposes. For example, as YAML anchors and aliases.
  • If 2 configuration files have duplicate top-level keys, but are placed into different environment paths (one in conf/base/, another in conf/local/, for example) then the last loaded path (conf/local/ in this case) takes precedence and overrides that key value. ConfigLoader.get(<pattern>, ...) will not raise any errors, however a DEBUG level log message will be emitted with the information on the over-ridden keys.

Additional configuration environments

In addition to the 2 built-in configuration environments, it is possible to create your own. Your project loads conf/base/ as the bottom-level configuration environment but allows you to overwrite it with any other environments that you create. You are be able to create environments like conf/server/, conf/test/, etc. Any additional configuration environments can be created inside conf folder and loaded by running the following command:

kedro run --env=test

If no env option is specified, this will default to using local environment to overwrite conf/base.

You can alternatively change the default environment by modifying the DEFAULT_RUN_ENV variable in src/run.py.

DEFAULT_RUN_ENV = "test"