CLI Config

Build your experiment configurations for complex projects with robustness, flexibility and simplicity

CLI Config: Lightweight library that provides routines to merge nested configs and set parameters from command line. It is also provide processing functions that can change the whole configuration before and after each config merge, config saving, config loading and at the end of config building. It also contains many routines to manipulate the config as flatten or nested dictionaries.

The package is initially designed for machine learning experiments where the number of parameters is huge and a lot of them have to be set by the user between each experiment. If your project matches this description, this package is for you!

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Make default config yaml file(s) in your project (configs are merged from left to right):

# main.py
from cliconfig import make_config

config = make_config('default1.yaml', 'default2.yaml')

Then launch your script with additional config(s) file(s) and parameters by command line. The additional configs are merged on the default one’s then the parameters are set.

python main.py --config first.yaml,second.yaml --param1=1 --subconfig.param2='foo'

By default, these additional configs cannot add new parameters to the default config (for security and retro-compatibility reasons).

Now you can get your configuration parameters in your script:

# Nested config dict as a native python dict
config.dict
# Get a parameter value (you can also set it or delete it)
config.foo1.foo2.bar

You can also load and save configs with cliconfig.save_config and cliconfig.load_config.

With processing

The library provides powerful tools to modify the configuration called “processings”. One of the possibility they add is to merge multiple configurations, copy a parameter on another, enforce type and more. To do so, simply adding the corresponding tags to your parameter names (on config files or CLI parameters).

For instance with these config files:

# main.yaml
path_1@merge_add: sub1.yaml
path_2@merge_add: sub2.yaml
config3.select@select: config3.param1

# sub1.yaml
config1:
  param@copy@type:int: config2.param
  param2@type:None|int: 1

# sub2.yaml
config2.param@type:int: 2
config3:
  param1@def: "[(config1.param2 + config2.param) / 2] * 2 if config2.param else None"
  param2: 1

Note that can also use YAML tags separated with “@” (like key: !tag@tag2 value) to add tags instead of putting them in the parameter name (like key@tag@tag2: value).

Here main.yaml will be interpreted like:

path_1: sub1.yaml
path_2: sub2.yaml
config1:
  param: 2  # the value of config2.param
  param2: 1
config2:
  param: 2
config3:
  select: config3.param1
  param1: [1.5, 1.5]
  # param2 is deleted because it is not in the selection

Then, all the parameters in config1 and config2 have enforced types (config2.param can also be None) and changing config2.param will also update config1.param accordingly (which is protected by direct update).

The default tags include:

@merge_add, @merge_before, and @merge_after: These tags merge the dictionary loaded from the specified value (which should be a YAML path) into the current configuration. @merge_add allows only the merging of new keys and is useful for splitting non-overlapping sub-configurations into multiple files. @merge_before merges the current dictionary onto the loaded one, while @merge_after merges the loaded dictionary onto the current one. These tags are used to organize the config files simply.
@copy: This tag copies a parameter from another key. The value should be a string that represents the flattened key. The copied value is then protected from further updates but will be updated if the copied key change during a merge.
@def: This tag evaluate an expression to define the parameter value. The value associated to a parameter tagged with @def can contain any parameter name of the configuration. The most useful operators and built-in functions are supported, the random and math packages are also supported as well as some (safe) numpy, jax, tensorflow, pytorch functions. If/else statements and comprehension lists are also supported.
@type:<my type>: This tag checks if the key matches the specified type <my type> after each update, even if the tag is no longer present. It tries to convert the type if it is not the good one. It supports basic types (except for tuples and sets, which are not handled by YAML) as well as unions (using “Union” or “|”), optional values, nested list, and nested dict. For instance: @type:List[Dict[str, int|float]].
@select: This tag select sub-config(s) to keep and delete the other sub-configs in the same parent config. The tagged key is not deleted if it is in the parent config.
@delete: This tag deletes the key from the config before merging.
@new: This tag allows adding new key(s) to the config that are not already present in the default config(s). It can be used for single parameter or a sub-config. Disclaimer: it is preferable to have exhaustive default config(s) instead of abusing this tag for readability and for security concerning typos.
@dict: This tag allows to have a dictionary object instead of a sub-config where you can modify the keys (see the [Edge cases](https://cliconfig.readthedocs.io/en/latest/edge_cases.html) section)

See Quickstart section of the documentation for more details and Processing section for advanced usage.

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