xinject 1.4.0

Lazy dependency injection.

• Introduction
• Documentation
• Install
• Quick Start
• Licensing

Introduction

Main focus is an easy way to create lazy universally injectable dependencies; in less magical way. It also leans more on the side of making it easier to get the dependency you need anywhere in the codebase.

py-xinject allows you to easily inject lazily created universal dependencies into whatever code that needs them, in an easy to understand and self-documenting way.

Documentation

📄 Detailed Documentation | 🐍 PyPi

Install

# via pip
pip install xinject

# via poetry
poetry add xinject

Quick Start

# This is the "my_resources.py" file/module.

import boto3
from xinject import DependencyPerThread


class S3(DependencyPerThread):
    def __init__(self, **kwargs):
        # Keeping this simple; a more complex version
        # may store the `kwargs` and lazily create the s3 resource
        # only when it's asked for (via a `@property or some such).

        self.resource = boto3.resource('s3', **kwargs)

To use this resource in codebase, you can do this:

# This is the "my_functions.py" file/module

from .my_resources import S3

def download_file(file_name, dest_path):
    # Get dependency
    s3_resource = S3.grab().resource
    s3_resource.Bucket('my-bucket').download_file(file_name, dest_path)

Inject a different version of the resource:

from .my_resources import S3
from .my_functions import download_file

us_west_s3_resource = S3(region_name='us-west-2')

def get_s3_file_from_us_west(file, dest_path):
    # Can use Dependencies as a context-manager,
    # inject `use_west_s3_resource` inside `with`:
    with us_west_s3_resource:
        download_file(file, dest_path)

# Can also use Dependencies as a function decorator,
# inject `use_west_s3_resource` whenever this method is called.
@us_west_s3_resource
def get_s3_file_from_us_west(file, dest_path):
    download_file(file, dest_path)

Licensing

This library is licensed under the MIT-0 License. See the LICENSE file.