> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/iii-hq/iii/llms.txt
> Use this file to discover all available pages before exploring further.

# Modules Overview

> Understanding the modular architecture of iii framework

Modules are the core building blocks of the iii framework. Each module provides specific functionality and can be configured independently through the `config.yaml` file.

## Architecture

The iii framework uses a **modular architecture** where each module:

* Implements the `Module` trait
* Can use different **adapters** for storage/communication backends
* Registers functions and triggers with the engine
* Runs independently with isolated configuration

## Available Modules

### Core Modules

These modules are enabled by default and provide essential functionality:

<CardGroup cols={2}>
  <Card title="HTTP" icon="globe" href="/modules/http">
    Expose functions as HTTP/REST endpoints
  </Card>

  <Card title="Queue" icon="list" href="/modules/queue">
    Asynchronous message queue with pub/sub
  </Card>

  <Card title="Cron" icon="clock" href="/modules/cron">
    Schedule functions with cron expressions
  </Card>

  <Card title="Stream" icon="wave-pulse" href="/modules/stream">
    Real-time WebSocket data streams
  </Card>

  <Card title="State" icon="database" href="/modules/state">
    Persistent key-value state management
  </Card>

  <Card title="Observability" icon="chart-line" href="/modules/observability">
    OpenTelemetry traces, metrics, and logs
  </Card>
</CardGroup>

## Module Configuration

Modules are configured in `config.yaml` under the `modules` section:

```yaml config.yaml theme={null}
modules:
  - class: modules::api::RestApiModule
    config:
      port: 3111
      host: 127.0.0.1
      
  - class: modules::queue::QueueModule
    config:
      adapter:
        class: modules::queue::RedisAdapter
        config:
          redis_url: redis://localhost:6379
```

## Adapter Pattern

Most modules support **pluggable adapters** for different backends:

```yaml theme={null}
modules:
  - class: modules::stream::StreamModule
    config:
      adapter:
        class: modules::stream::adapters::RedisAdapter  # Redis backend
        config:
          redis_url: redis://localhost:6379
```

Common adapter options:

* **KvStore** - File-based or in-memory storage (default)
* **RedisAdapter** - Redis backend for distributed systems
* **Custom** - Implement your own adapter

## Module Lifecycle

1. **Create** - Module is instantiated with configuration
2. **Initialize** - Registers functions and triggers
3. **Start** - Background tasks begin (optional)
4. **Destroy** - Cleanup on shutdown

## Common Patterns

### Triggers

Modules register trigger types that invoke functions based on events:

```typescript theme={null}
export default iii({
  triggers: {
    'on-user-create': {
      type: 'queue',
      config: { topic: 'users.created' },
    },
  },
});
```

### Functions

Modules expose functions callable via SDK or other modules:

```typescript theme={null}
// Queue module function
await client.call('queue.enqueue', {
  topic: 'notifications',
  data: { userId: 123 },
});
```

## Next Steps

<CardGroup cols={2}>
  <Card title="HTTP Module" icon="globe" href="/modules/http">
    Learn about REST API endpoints
  </Card>

  <Card title="Custom Modules" icon="code" href="/modules/custom-modules">
    Build your own modules
  </Card>
</CardGroup>