https://github.com/soldni/necessary

Python Package to enforce optional dependencies
https://github.com/soldni/necessary

python python3

Last synced: 6 days ago
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Python Package to enforce optional dependencies

• Host: GitHub
• URL: https://github.com/soldni/necessary
• Owner: soldni
• License: apache-2.0
• Created: 2022-08-24T22:43:02.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2024-01-22T21:35:45.000Z (10 months ago)
• Last Synced: 2024-11-06T15:08:27.632Z (8 days ago)
• Topics: python, python3
• Language: Python
• Homepage: https://pypi.org/project/necessary
• Size: 45.9 KB
• Stars: 4
• Watchers: 1
• Forks: 0
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Necessary

Python package that can be used to enforce optional dependencies are installed when a module is imported. Necessary stands for "Now Ensures Correct Existence of Select Software, or Add Resource Yourself!"

Necessary is available on [PyPI](https://pypi.org/project/necessary/), and can be installed with the following command:

```bash

pip install necessary

```

## How to Use

### As Context Manager

Simply use `necessary.necessary` to get a context manager import a module.

```python

from necessary import necessary

with necessary('torch'):

    # this will raise a nicely written error if

    # torch is not installed

    import torch

```

If you want to just soft fail when a necessary module is not available (that is, have necessary return `False`), use `soft`:

```python

try:

    # assuming torch is not installed

    necessary('torch')

except ImportError:

    out = necessary('torch', soft=True)

    assert out is False

```

If you want to request a minimum version, use Python's requirements syntax:

```python

with necessary('torch>=1.12.0'):

    # this will raise an error if

    # torch is not installed or if

    # the installed version is less than 0.12.0

    import torch

```

You can also check multiple packages in the same `necessary` call, or combine multiple requirements:

```python

with necessary(['torch>=1.12.0', 'numpy>=1.20,<1.25']):

    # this will raise an error if torch >= 1.12.0 or numpy are not installed

    import torch

    import numpy

```

Finally, we can customize the message that is raised if a necessary module is not installed; use `{module_name}` and `{module_version}` to insert the module name and version respectively.

```python

with necessary('torch', message='I am missing {module_name}/{module_version}'):

    import torch

```

### As Function or Class Decorator

You can also use `necessary` as a function or class decorator:

```python

from necessary import Necessary

# decorating a function

@Necessary('torch')

def my_function():

    import torch

# decorating a class

@Necessary('torch')

class MyClass:

    def __init__(self):

        import torch

```

All of the same functionality is available in the decorator form as in the context manager form.