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https://github.com/linkedin/smart-arg

Smart Arguments Suite (smart-arg) is a slim and handy python lib that helps one work safely and conveniently with command line arguments.
https://github.com/linkedin/smart-arg

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Smart Arguments Suite (smart-arg) is a slim and handy python lib that helps one work safely and conveniently with command line arguments.

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# Smart Argument Suite (`smart-arg`)

[![GitHub tag](https://img.shields.io/github/tag/linkedin/smart-arg.svg)](https://GitHub.com/linkedin/smart-arg/tags/)
[![PyPI version](https://img.shields.io/pypi/v/smart-arg.svg)](https://pypi.python.org/pypi/smart-arg/)

Smart Argument Suite (`smart-arg`) is a slim and handy Python library that helps one work safely and conveniently
with the arguments that are represented by an immutable argument container class' fields
([`NamedTuple`](https://docs.python.org/3.7/library/typing.html?highlight=namedtuple#typing.NamedTuple) or
[`dataclass`](https://docs.python.org/3.7/library/dataclasses.html#dataclasses.dataclass) out-of-box),
and passed through command-line interfaces.

`smart-arg` promotes arguments type-safety, enables IDEs' code autocompletion and type hints
functionalities, and helps one produce correct code.

![](smart-arg-demo.gif)

## Quick start

The [`smart-arg`](https://pypi.org/project/smart-arg/) package is available through `pip`.
```shell
pip3 install smart-arg
```

Users can bring or define, if not already, their argument container class -- a `NamedTuple` or `dataclass`,
and then annotate it with `smart-arg` decorator `@arg_suite` in their Python scripts.

Now an argument container class instance, e.g. `my_arg` of `MyArg` class, once created, is ready to be serialized by the `smart-arg` API --
`my_arg.__to_argv__()` to a sequence of strings, passed through the command-line interface
and then deserialized back to an instance again by `my_arg = MyArg.__from_argv__(sys.argv[1:])`.

```python
import sys
from typing import NamedTuple, List, Tuple, Dict, Optional
from smart_arg import arg_suite

# Define the argument container class
@arg_suite
class MyArg(NamedTuple):
"""
MyArg is smart! (docstring goes to description)
"""
nn: List[int] # Comments go to argparse help
a_tuple: Tuple[str, int] # a random tuple argument
encoder: str # Text encoder type
h_param: Dict[str, int] # Hyperparameters
batch_size: Optional[int] = None
adp: bool = True # bool is a bit tricky
embedding_dim: int = 100 # Size of embedding vector
lr: float = 1e-3 # Learning rate

def cli_interfaced_job_scheduler():
"""
This is to be called by the job scheduler to set up the job launching command,
i.e., producer side of the Python job arguments
"""
# Create the argument container instance
my_arg = MyArg(nn=[3], a_tuple=("str", 1), encoder='lstm', h_param={}, adp=False) # The patched argument container class requires keyword arguments to instantiate the class

# Serialize the argument to command-line representation
argv = my_arg.__to_argv__()
cli = 'my_job.py ' + ' '.join(argv)
# Schedule the job with command line `cli`
print(f"Executing job:\n{cli}")
# Executing job:
# my_job.py --nn 3 --a_tuple str 1 --encoder lstm --h_param --batch_size None --adp False --embedding_dim 100 --lr 0.001

def my_job(my_arg: MyArg):
"""
This is the actual job defined by the input argument my_arg,
i.e., consumer side of the Python job arguments
"""
print(my_arg)
# MyArg(nn=[3], a_tuple=('str', 1), encoder='lstm', h_param={}, batch_size=None, adp=False, embedding_dim=100, lr=0.001)

# `my_arg` can be used in later script with a typed manner, which help of IDEs (type hints and auto completion)
# ...
print(f"My network has {len(my_arg.nn)} layers with sizes of {my_arg.nn}.")
# My network has 1 layers with sizes of [3].

# my_job.py
if __name__ == '__main__':
# Deserialize the command-line representation of the argument back to a container instance
arg_deserialized: MyArg = MyArg.__from_argv__(sys.argv[1:]) # Equivalent to `MyArg(None)`, one positional arg required to indicate the arg is a command-line representation.
my_job(arg_deserialized)
```

```shell-session
> python my_job.py -h
usage: my_job.py [-h] --nn [int [int ...]] --a_tuple str int --encoder str
--h_param [str:int [str:int ...]] [--batch_size int]
[--adp {True,False}] [--embedding_dim int] [--lr float]

MyArg is smart! (docstring goes to description)

optional arguments:
-h, --help show this help message and exit
--nn [int [int ...]] (List[int], required) Comments go to argparse help
--a_tuple str int (Tuple[str, int], required) a random tuple argument
--encoder str (str, required) Text encoder type
--h_param [str:int [str:int ...]]
(Dict[str, int], required) Hyperparameters
--batch_size int (Optional[int], default: None)
--adp {True,False} (bool, default: True) bool is a bit tricky
--embedding_dim int (int, default: 100) Size of embedding vector
--lr float (float, default: 0.001) Learning rate

```
## Promoted practices
* Focus on defining the arguments diligently, and let the `smart-arg`
(backed by [argparse.ArgumentParser](https://docs.python.org/3/library/argparse.html#argumentparser-objects))
work its magic around command-line interface.
* Always work directly with argument container class instances when possible, even if you only need to generate the command-line representation.
* Stick to the default behavior and the basic features, think twice before using any of the [advanced features](https://smart-arg.readthedocs.io/en/latest/advanced.html#advanced-usages).

## More detail
For more features and implementation detail, please refer to the [documentation](https://smart-arg.readthedocs.io/).

## Contributing

Please read [CONTRIBUTING.md](CONTRIBUTING.md) for details on our code of conduct, and the process for submitting pull requests to us.

## License

This project is licensed under the BSD 2-CLAUSE LICENSE - see the [LICENSE.md](LICENSE.md) file for details