pico-ioc 2.0.2

A minimalist, zero-dependency Inversion of Control (IoC) container for Python.

📦 Pico-IoC: A Robust, Async-Native IoC Container for Python

Pico-IoC is a lightweight, async-ready, decorator-driven IoC container built for clarity, testability, and performance. It brings Inversion of Control and dependency injection to Python in a deterministic, modern, and framework-agnostic way.

🐍 Requires Python 3.10+

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⚖️ Core Principles

• Single Purpose – Do one thing: dependency management.
• Declarative – Use simple decorators (@component, @factory, @configuration) instead of config files or YAML magic.
• Deterministic – No hidden scanning or side-effects; everything flows from an explicit init().
• Async-Native – Fully supports async providers, async lifecycle hooks, and async interceptors.
• Fail-Fast – Detects missing bindings and circular dependencies at bootstrap.
• Testable by Design – Use overrides and profiles to swap components instantly.
• Zero Core Dependencies – Built entirely on the Python standard library. Optional features may require external packages (see Installation).

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🚀 Why Pico-IoC?

As Python systems evolve, wiring dependencies by hand becomes fragile and unmaintainable. Pico-IoC eliminates that friction by letting you declare how components relate — not how they’re created.

Feature	Manual Wiring	With Pico-IoC
Object creation	svc = Service(Repo(Config()))	svc = container.get(Service)
Replacing deps	Monkey-patch	overrides={Repo: FakeRepo()}
Coupling	Tight	Loose
Testing	Painful	Instant
Async support	Manual	Built-in

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🧩 Highlights (v2.0.0)

• Full redesign: unified architecture with simpler, more powerful APIs.
• Async-aware AOP system — method interceptors via @intercepted_by.
• Typed configuration — dataclasses with JSON/YAML/env sources.
• Scoped resolution — singleton, prototype, request, session, transaction.
• UnifiedComponentProxy — transparent lazy/AOP proxy supporting serialization.
• Tree-based configuration runtime with reusable adapters and discriminators.
• Observable container context with stats, health checks, and async cleanup.

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📦 Installation

pip install pico-ioc

For optional features, you can install extras:

• YAML Configuration:

  pip install pico-ioc[yaml]
  

  (Requires PyYAML)

• Dependency Graph Export:

  pip install pico-ioc[graphviz]
  

  (Requires the graphviz Python package and the Graphviz command-line tools)

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⚙️ Quick Example

from dataclasses import dataclass
from pico_ioc import component, configuration, init

@configuration
@dataclass
class Config:
    db_url: str = "sqlite:///demo.db"

@component
class Repo:
    def __init__(self, cfg: Config):
        self.cfg = cfg
    def fetch(self):
        return f"fetching from {self.cfg.db_url}"

@component
class Service:
    def __init__(self, repo: Repo):
        self.repo = repo
    def run(self):
        return self.repo.fetch()

container = init(modules=[__name__])
svc = container.get(Service)
print(svc.run())

Output:

fetching from sqlite:///demo.db

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🧪 Testing with Overrides

class FakeRepo:
    def fetch(self): return "fake-data"

container = init(modules=[__name__], overrides={Repo: FakeRepo()})
svc = container.get(Service)
assert svc.run() == "fake-data"

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🩺 Lifecycle & AOP

from pico_ioc import intercepted_by, MethodInterceptor, MethodCtx

class LogInterceptor(MethodInterceptor):
    def invoke(self, ctx: MethodCtx, call_next):
        print(f"→ calling {ctx.name}")
        res = call_next(ctx)
        print(f"← {ctx.name} done")
        return res

@component
class Demo:
    @intercepted_by(LogInterceptor)
    def work(self):
        return "ok"

c = init(modules=[__name__])
c.get(Demo).work()

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📖 Documentation

The full documentation is available within the docs/ directory of the project repository. Start with docs/README.md for navigation.

• Getting Started: docs/getting-started.md
• User Guide: docs/user-guide/README.md
• Advanced Features: docs/advanced-features/README.md
• Observability: docs/observability/README.md
• Integrations: docs/integrations/README.md
• Cookbook (Patterns): docs/cookbook/README.md
• Architecture: docs/architecture/README.md
• API Reference: docs/api-reference/README.md
• ADR Index: docs/adr/README.md

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🧩 Development

pip install tox
tox

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🧾 Changelog

See CHANGELOG.md — Full redesign for v2.0.0.

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📜 License

MIT — LICENSE