hydra_config.resolvers

This module contains custom resolvers for OmegaConf.

Functions

register_new_resolver(name[, replace])	Register a new resolver with OmegaConf.
search_resolver([key, mode, depth])	This method will recursively search up the parent chain for the key and return
parent_resolver([key, mode])	This resolver is a wrapper around the search resolver with a default mode of
eval_resolver(key, /, *, _root_)	This resolver will evaluate the key as a python expression. This is useful for
glob_resolver(pattern[, config])	This resolver will return a list of keys that match the pattern. This is useful
hydra_select(key[, default])	This is similar to the regular hydra resolver, but this won't through an error
path_resolver(*parts)	Simple resolver to join paths together.
read_resolver(path)	Simple resolver to read a file.
custom_resolver(target[, default])	This resolver is a wrapper around the select resolver to grab an entry in a
float_to_str_resolver(value)	This resolver will convert a float to a string. This is useful for saving
locate_resolver(fn, /[, cast_to])	This resolver will locate an object using the hydra.utils.get_object()
getitem_resolver(obj, key)	This resolver will get an item from a list.
target_resolver(target, /, *args)	This is a resolver which serves as a proxy for the _target_ attribute used
instantiate_resolver(target, /, *args, _root_)	This resolver will instantiate a target using the HydraContainerConfig. If the

Module Contents

register_new_resolver(name, replace=True, **kwargs)

Register a new resolver with OmegaConf.

Parameters:

• name (str) – The name of the resolver.

• replace (bool) – Whether to replace the resolver if it already exists.

• **kwargs – Additional keyword arguments to pass to OmegaConf.register_new_resolver.

search_resolver(key=None, /, mode='value', *, depth=0, _parent_)

This method will recursively search up the parent chain for the key and return the value. If the key is not found, will raise a KeyError.

For instance, a heavily nested value might want to access a value some level higher but it may be hazardous to use relative paths (i.e. ${..key}) since the config may be changed. Instead, we’ll search up for a specific key to set the value to. Helpful for setting unique names for an object in a nested config.

Note

This technically uses hidden attributes (i.e. _parent).

Parameters:

• key (str | None) – The key to search for. Could be none (like when mode is “parent_key”).

• mode (Optional[str]) – The mode to use. Defaults to “value”. Available modes: - “value”: Will return the value of the found key. Key must be set. - “parent_key”: Will return the parent’s key. If key is None, won’t do any recursion and will return the parent’s key. - “path”: Will return the path to the key.

• depth (Optional[int]) – The depth of the search. Used internally in this method and unsettable from the config. Avoids checking the parent key.

• _parent_ (DictConfig) – The parent config to search in.

parent_resolver(key=None, mode='parent_key', *, _parent_)

This resolver is a wrapper around the search resolver with a default mode of “parent_key”. This will return the parent’s key.

eval_resolver(key, /, *, _root_)

This resolver will evaluate the key as a python expression. This is useful for evaluating any expression. The resolver calls safe_eval(), so only a (safe) subset of python is available.

glob_resolver(pattern, config=None, /, *, _root_)

This resolver will return a list of keys that match the pattern. This is useful for selecting a subset of keys in a config. The pattern should be a regex pattern. If the config is a string, it will be treated as a dotpath to a config.

hydra_select(key, default=None, /, *, _root_)

This is similar to the regular hydra resolver, but this won’t through an error if the global hydra config is unset. Instead, it will return another interpolation using dotpath notation directly. As in, ${hydra_select:runtime.choices.test}, if HydraConfig is unset, will return ${hydra.runtime.choices.test}.

path_resolver(*parts)

Simple resolver to join paths together.

read_resolver(path)

Simple resolver to read a file.

custom_resolver(target, default=None, /)

This resolver is a wrapper around the select resolver to grab an entry in a parent custom field.

float_to_str_resolver(value)

This resolver will convert a float to a string. This is useful for saving floats as strings in a config for a filename. All periods will be replaced with ‘p’ and all negatives will be replaced with ‘n’; e.g. -0.5 will be converted to 'n0p5'.

locate_resolver(fn, /, cast_to=None)

This resolver will locate an object using the hydra.utils.get_object() method.

getitem_resolver(obj, key)

This resolver will get an item from a list.

target_resolver(target, /, *args)

This is a resolver which serves as a proxy for the _target_ attribute used in hydra. Basically target will be defined as _target_ and the rest of the attributes will be passed as arguments to the target. You should always default to using _target_ directly in your config, but because interpolations may be resolved prior to or instead of instantiate, it may be desired to resolve interpolations before instantiations.

instantiate_resolver(target, /, *args, _root_)

This resolver will instantiate a target using the HydraContainerConfig. If the target is a string, it will be resolved using the target_resolver. If the target is a DictConfig, it will be passed directly to the HydraContainerConfig.instantiate method.