minydra 🦎

Minimal Python command-line parser inspired by Facebook's Hydra.

Easily parse arbitrary arguments from the command line without dependencies:

pip install minydra

Usage

examples/parser.py

from minydra.parser import Parser

if __name__ == "__main__":
    parser = Parser(
        verbose=0, # print received args
        allow_overwrites=False, # allow repeating args in the command-line
        warn_overwrites=True, # warn repeating args if they are allowed
        parse_env=True, # get environment variable
        warn_env=True, # warn if an environment variable is specified but not found
    )
    args = parser.args.pretty_print().resolve().pretty_print() # notice .resolve() transforms dotted.keys into nested dicts

examples/decorator.py

import minydra
from minydra.dict import MinyDict

@minydra.parse_args(verbose=0, allow_overwrites=False) # Parser's init args work here
def main(args: MinyDict) -> None:
    args.resolve().pretty_print()


if __name__ == "__main__":
    main()

Parsing

• Simple strings are parsed to float and int automatically.
• A single keyword will be interpreted as a positive flag.
• A single keyword starting with - will be interpreted as a negative flag.
• If parse_env is True, environment variables are evaluated.

$ python decorator.py outdir=$HOME/project save -log learning_rate=1e-4 batch_size=64
╭───────────────────────────────────────────╮
│ batch_size    : 64                        │
│ learning_rate : 0.0001                    │
│ log           : False                     │
│ outdir        : /Users/victor/project     │
│ save          : True                      │
╰───────────────────────────────────────────╯

• dotted keys will be resolved to nested dictionary keys:

$ python decorator.py server.conf.port=8000
╭─────────────────────────╮
│ server                  │
│     conf                │
│         port : 8000     │
╰─────────────────────────╯

• Using ast.literal_eval(value), minydra will try and parse more complex values for arguments as lists or dicts. Those should be specified as strings:

$ python examples/decorator.py layers="[1, 2, 3]" norms="{'conv': 'batch', 'epsilon': 1e-3}"
╭──────────────────────────────────────────────────╮
│ layers : [1, 2, 3]                               │
│ norms  : {'conv': 'batch', 'epsilon': 0.001}     │
╰──────────────────────────────────────────────────╯

MinyDict

Minydra's args are a custom lightweight wrapper around native dict which allows for dot access (args.key), resolving dotted keys into nested dicts and pretty printing sorted keys in a box with nested dicts indented. If a key does not exist, it will not fail, rather return None (as dict.get(key, None)).

a MinyDict inherits from dict so usual methods work .keys(), .items() etc.

In [1]: from minydra.dict import MinyDict

In [2]: args = MinyDict({"foo": "bar", "yes.no.maybe": "idontknow"}).pretty_print()
╭──────────────────────────────╮
│ foo          : bar           │
│ yes.no.maybe : idontknow     │
╰──────────────────────────────╯

In [3]: args.resolve().pretty_print()
╭───────────────────────────────╮
│ foo : bar                     │
│ yes                           │
│     no                        │
│         maybe : idontknow     │
╰───────────────────────────────╯

In [4]: "foo" in args
Out[4]: True

In [5]: "rick" in args
Out[5]: False

In [6]: args.morty is None
Out[6]: True

In [7]: args.items()
Out[7]: dict_items([('foo', 'bar'), ('yes', {'no': {'maybe': 'idontknow'}})])

Forcing types

Adding ___<type> to a key will force this type to the value:

$ python examples/decorator.py n_jobs___str=04 job=01 chips___list=hello 
╭────────────────────────────────────────╮
│ chips  : ['h', 'e', 'l', 'l', 'o']     │
│ job    : 1                             │
│ n_jobs : 04                            │
╰────────────────────────────────────────╯

Known types are defined in Parser.known_types and the separator (___) in Parser.type_separator

In [1]: from minydra import Parser

In [2]: Parser.known_types
Out[2]: {'bool', 'dict', 'float', 'int', 'list', 'set', 'str'}