# Design Concepts Overview

The Sugarcoat philosophy is centered around four key pillars: [**Modular Execution**](#1-the-component-smart-execution), [**Active Resilience**](#2-active-resilience-status--fallbacks), [**Event-Driven Behavior**](#3-dynamic-behavior-events--actions), and [**Centralized Orchestration**](#4-orchestration--recipes-launcher).

A [Component](#1-the-component-smart-execution) is the main execution unit in Sugarcoat, each component is configured with [Inputs/Outputs](topics.md) and [Fallback](#2-active-resilience-status--fallbacks) behaviors. Additionally, each component updates its own [Health Status](#2-active-resilience-status--fallbacks), to keep track of the well/mal-functioning of the component. Components can be handled and reconfigured dynamically at runtime using [Events](#3-dynamic-behavior-events--actions) and [Actions](#3-dynamic-behavior-events--actions). Events, Actions and Components are configured in imperative scripts called "Recipes" and brought to life using the [Launcher](#4-orchestration--recipes-launcher).


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```{image} /_static/images/diagrams/component_light.png
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## 1. The Component: Smart Execution

At the heart of the system is the [Component](component.md). Unlike a standard ROS2 node, a Sugarcoat Component is Lifecycle-managed and Health-aware by default. It executes a specific logic (e.g., a path planner, a driver, or a controller), and validates its own configuration automatically.

## 2. Active Resilience: Status & Fallbacks

Robots fail. Sugarcoat Components are designed to handle failure gracefully rather than crashing.

- [**Health Status**](status.md): Every component continuously reports its internal state, distinguishing between Algorithm failures (e.g., "no path found"), Component failures (e.g., "driver crash"), or System failures (e.g., "missing input").

- [**Fallbacks**](fallbacks.md): When a failure is detected, the component automatically triggers pre-configured recovery strategies—such as retrying an operation, re-initializing a driver, or safely shutting down—without requiring external intervention.

## 3. Dynamic Behavior: Events & Actions

To create reactive autonomy, Sugarcoat layers an **Event-Driven system** on top of standard data flows.

- [**Events**](events.md): These act as triggers that monitor ROS2 topics for specific conditions (e.g., "Battery < 20%", "Target Lost", or "New Terrain Detected").

- [**Actions**](actions.md): When an Event triggers (or a Fallback activates), an Action is executed. Actions can reconfigure components, switch controllers, start/stop processes, or send goals to other nodes.

## 4. Orchestration & Recipes Launcher

Finally, the system is brought to life and supervised by the [**Launcher**](./launcher.md), a Pythonic interface to define and deploy your system. It supports running components in Multi-threaded or Multi-process modes, managing their lifecycles automatically and handling event/action coordination.