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In this video, I explore how Dependency Injection can make your Python code cleaner, more testable, and easier to extend, using a real-world data pipeline example. I start with a tightly coupled version and progressively refactor it using manual injection, a lightweight custom DI container, and even show how frameworks like FastAPI handle DI under the hood.
Design pattern playlist: https://www.youtube.com/playlist?list=PLC0nd42SBTaNf0bVJVd9e2oBV-mcUuxS0
🔥 GitHub Repository: https://git.arjan.codes/2025/di.
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🔖 Chapters:
0:00 Intro
0:57 The Problem: No DI
1:29 What Is Dependency Injection?
2:13 Refactoring with Manual DI
17:19 Going Further: A Simple DI Container
28:04 Dependency Injection in FastAPI
29:53 Use Cases for Dependency Injection
30:52 Final Thoughts
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