chore(release): v0.8.1 (#35)

chore(release): 0.8.1

Co-authored-by: cuddle-please <bot@cuddle.sh>
Reviewed-on: #35

CHANGELOG.md

@@ -6,6 +6,31 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.8.1] - 2025-08-09
+
+### Other
+- error logging
+
+## [0.8.0] - 2025-08-08
+
+### Added
+- add docs
+- update readme
+
+## [0.7.5] - 2025-07-24
+
+### Added
+- print big inner
+
+### Other
+- more error correction
+- correct error test to not be as verbose
+
+## [0.7.4] - 2025-07-24
+
+### Added
+- cleanup aggregate error for single error
+
 ## [0.7.3] - 2025-07-24
 
 ### Added

Cargo.lock

@@ -278,7 +278,7 @@ dependencies = [
 
 [[package]]
 name = "notmad"
-version = "0.7.2"
+version = "0.7.5"
 dependencies = [
  "anyhow",
  "async-trait",

Cargo.toml

@@ -3,7 +3,7 @@ members = ["crates/*"]
 resolver = "2"
 
 [workspace.package]
-version = "0.7.3"
+version = "0.8.1"
 
 [workspace.dependencies]
 mad = { path = "crates/mad" }

README.md

@@ -1,39 +1,92 @@
-# MAD 
+# MAD - Lifecycle Manager for Rust Applications
 
-Mad is a life-cycle manager for long running rust operations.
+[![Crates.io](https://img.shields.io/crates/v/notmad.svg)](https://crates.io/crates/notmad)
+[![Documentation](https://docs.rs/notmad/badge.svg)](https://docs.rs/notmad)
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 
-- Webservers
+## Overview
-- Queue bindings
-- gRPC servers etc
-- Cron runners
 
-It is supposed to be the main thing the application runs, and everything from it is spawned and managed by it.
+MAD is a robust lifecycle manager designed for long-running Rust operations. It provides a simple, composable way to manage multiple concurrent services within your application, handling graceful startup and shutdown automatically.
+
+### Perfect for:
+- 🌐 Web servers
+- 📨 Queue consumers and message processors  
+- 🔌 gRPC servers
+- ⏰ Cron job runners
+- 🔄 Background workers
+- 📡 Any long-running async operations
+
+## Features
+
+- **Component-based architecture** - Build your application from composable, reusable components
+- **Graceful shutdown** - Automatic handling of shutdown signals with proper cleanup
+- **Concurrent execution** - Run multiple components in parallel with tokio
+- **Error handling** - Built-in error propagation and logging
+- **Cancellation tokens** - Coordinate shutdown across all components
+- **Minimal boilerplate** - Focus on your business logic, not lifecycle management
+
+## Installation
+
+Add MAD to your `Cargo.toml`:
+
+```toml
+[dependencies]
+notmad = "0.7.5"
+tokio = { version = "1", features = ["full"] }
+async-trait = "0.1"
+```
+
+## Quick Start
+
+Here's a simple example of a component that simulates a long-running server:
 
 ```rust
-struct WaitServer {}
+use mad::{Component, Mad};
+use async_trait::async_trait;
+use tokio_util::sync::CancellationToken;
+
+// Define your component
+struct WebServer {
+    port: u16,
+}
 
 #[async_trait]
-impl Component for WaitServer {
+impl Component for WebServer {
     fn name(&self) -> Option<String> {
-        Some("NeverEndingRun".into())
+        Some(format!("WebServer on port {}", self.port))
     }
 
     async fn run(&self, cancellation: CancellationToken) -> Result<(), mad::MadError> {
-        let millis_wait = rand::thread_rng().gen_range(50..1000);
+        println!("Starting web server on port {}", self.port);
         
-        // Simulates a server running for some time. Is normally supposed to be futures blocking indefinitely
+        // Your server logic here
-        tokio::time::sleep(std::time::Duration::from_millis(millis_wait)).await;
+        // The cancellation token will be triggered on shutdown
+        tokio::select! {
+            _ = cancellation.cancelled() => {
+                println!("Shutting down web server");
+            }
+            _ = self.serve() => {
+                println!("Server stopped");
+            }
+        }
         
         Ok(())
     }
 }
 
+impl WebServer {
+    async fn serve(&self) {
+        // Simulate a running server
+        tokio::time::sleep(std::time::Duration::from_secs(3600)).await;
+    }
+}
+
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
+    // Build and run your application
     Mad::builder()
-        .add(WaitServer {})
+        .add(WebServer { port: 8080 })
-        .add(WaitServer {})
+        .add(WebServer { port: 8081 })  // You can add multiple instances
-        .add(WaitServer {})
         .run()
         .await?;
 
@@ -41,11 +94,75 @@ async fn main() -> anyhow::Result<()> {
 }
 ```
 
+## Advanced Usage
+
+### Custom Components
+
+Components can be anything that implements the `Component` trait:
+
+```rust
+use mad::{Component, Mad};
+use async_trait::async_trait;
+
+struct QueueProcessor {
+    queue_name: String,
+}
+
+#[async_trait]
+impl Component for QueueProcessor {
+    fn name(&self) -> Option<String> {
+        Some(format!("QueueProcessor-{}", self.queue_name))
+    }
+
+    async fn run(&self, cancellation: CancellationToken) -> Result<(), mad::MadError> {
+        while !cancellation.is_cancelled() {
+            // Process messages from queue
+            self.process_next_message().await?;
+        }
+        Ok(())
+    }
+}
+```
+
+### Error Handling
+
+MAD provides comprehensive error handling through the `MadError` type with automatic conversion from `anyhow::Error`:
+
+```rust
+async fn run(&self, cancellation: CancellationToken) -> Result<(), mad::MadError> {
+    // Errors automatically convert from anyhow::Error to MadError
+    database_operation().await?;
+    
+    // Or return explicit errors
+    if some_condition {
+        return Err(anyhow::anyhow!("Something went wrong").into());
+    }
+    
+    Ok(())
+}
+```
+
 ## Examples
 
-Can be found (here)[crates/mad/examples]
+Check out the [examples directory](crates/mad/examples) for more detailed examples:
 
-- basic
+- **basic** - Simple component lifecycle
-- fn
+- **fn** - Using functions as components
-- signals
+- **signals** - Handling system signals
-- error_log
+- **error_log** - Error handling and logging
+
+## Contributing
+
+Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.
+
+## License
+
+This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.
+
+## Author
+
+Created and maintained by [kjuulh](https://github.com/kjuulh)
+
+## Repository
+
+Find the source code at [https://github.com/kjuulh/mad](https://github.com/kjuulh/mad)

crates/mad/examples/comprehensive/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "mad-comprehensive-example"
+version = "0.1.0"
+edition = "2021"
+
+[[bin]]
+name = "comprehensive"
+path = "main.rs"
+
+[dependencies]
+notmad = { path = "../.." }
+tokio = { version = "1", features = ["full"] }
+tokio-util = "0.7"
+async-trait = "0.1"
+anyhow = "1"
+tracing = "0.1"
+tracing-subscriber = "0.3"
+rand = "0.8"

crates/mad/examples/comprehensive/main.rs

@@ -0,0 +1,332 @@
+//! Comprehensive example demonstrating MAD's full capabilities.
+//!
+//! This example shows:
+//! - Multiple component types (struct, closure, conditional)
+//! - Component lifecycle (setup, run, close)
+//! - Error handling and propagation
+//! - Graceful shutdown with cancellation tokens
+//! - Concurrent component execution
+
+use async_trait::async_trait;
+use notmad::{Component, Mad, MadError};
+use std::sync::Arc;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use tokio::time::{Duration, interval};
+use tokio_util::sync::CancellationToken;
+use tracing::{error, info, warn};
+
+/// A web server component that simulates handling HTTP requests.
+struct WebServer {
+    port: u16,
+    request_count: Arc<AtomicUsize>,
+}
+
+#[async_trait]
+impl Component for WebServer {
+    fn name(&self) -> Option<String> {
+        Some(format!("web-server-{}", self.port))
+    }
+
+    async fn setup(&self) -> Result<(), MadError> {
+        info!("Setting up web server on port {}", self.port);
+        // In a real application, you might:
+        // - Bind to the port
+        // - Set up TLS certificates
+        // - Initialize middleware
+        tokio::time::sleep(Duration::from_millis(100)).await;
+        info!("Web server on port {} is ready", self.port);
+        Ok(())
+    }
+
+    async fn run(&self, cancellation: CancellationToken) -> Result<(), MadError> {
+        info!("Web server on port {} started", self.port);
+        let mut interval = interval(Duration::from_secs(1));
+
+        while !cancellation.is_cancelled() {
+            tokio::select! {
+                _ = cancellation.cancelled() => {
+                    info!("Web server on port {} received shutdown signal", self.port);
+                    break;
+                }
+                _ = interval.tick() => {
+                    // Simulate handling requests
+                    let count = self.request_count.fetch_add(1, Ordering::Relaxed);
+                    info!("Server on port {} handled request #{}", self.port, count + 1);
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    async fn close(&self) -> Result<(), MadError> {
+        info!("Shutting down web server on port {}", self.port);
+        // In a real application, you might:
+        // - Drain existing connections
+        // - Save server state
+        // - Close database connections
+        tokio::time::sleep(Duration::from_millis(200)).await;
+        let total = self.request_count.load(Ordering::Relaxed);
+        info!(
+            "Web server on port {} shut down. Total requests handled: {}",
+            self.port, total
+        );
+        Ok(())
+    }
+}
+
+/// A background job processor that simulates processing tasks from a queue.
+struct JobProcessor {
+    queue_name: String,
+    processing_interval: Duration,
+}
+
+#[async_trait]
+impl Component for JobProcessor {
+    fn name(&self) -> Option<String> {
+        Some(format!("job-processor-{}", self.queue_name))
+    }
+
+    async fn setup(&self) -> Result<(), MadError> {
+        info!("Connecting to queue: {}", self.queue_name);
+        // Simulate connecting to a message queue
+        tokio::time::sleep(Duration::from_millis(150)).await;
+        Ok(())
+    }
+
+    async fn run(&self, cancellation: CancellationToken) -> Result<(), MadError> {
+        info!("Job processor for {} started", self.queue_name);
+        let mut interval = interval(self.processing_interval);
+        let mut job_count = 0;
+
+        loop {
+            tokio::select! {
+                _ = cancellation.cancelled() => {
+                    info!("Job processor for {} stopping...", self.queue_name);
+                    break;
+                }
+                _ = interval.tick() => {
+                    job_count += 1;
+                    info!("Processing job #{} from {}", job_count, self.queue_name);
+
+                    // Simulate job processing
+                    tokio::time::sleep(Duration::from_millis(100)).await;
+
+                    // Simulate occasional errors (but don't fail the component)
+                    if job_count % 10 == 0 {
+                        warn!("Job #{} from {} required retry", job_count, self.queue_name);
+                    }
+                }
+            }
+        }
+
+        info!(
+            "Job processor for {} processed {} jobs",
+            self.queue_name, job_count
+        );
+        Ok(())
+    }
+
+    async fn close(&self) -> Result<(), MadError> {
+        info!("Disconnecting from queue: {}", self.queue_name);
+        tokio::time::sleep(Duration::from_millis(100)).await;
+        Ok(())
+    }
+}
+
+/// A health check component that monitors system health.
+struct HealthChecker {
+    check_interval: Duration,
+}
+
+#[async_trait]
+impl Component for HealthChecker {
+    fn name(&self) -> Option<String> {
+        Some("health-checker".to_string())
+    }
+
+    async fn run(&self, cancellation: CancellationToken) -> Result<(), MadError> {
+        info!("Health checker started");
+        let mut interval = interval(self.check_interval);
+
+        while !cancellation.is_cancelled() {
+            tokio::select! {
+                _ = cancellation.cancelled() => {
+                    info!("Health checker stopping...");
+                    break;
+                }
+                _ = interval.tick() => {
+                    // Simulate health checks
+                    let cpu_usage = rand::random::<f32>() * 100.0;
+                    let memory_usage = rand::random::<f32>() * 100.0;
+
+                    info!("System health: CPU={:.1}%, Memory={:.1}%", cpu_usage, memory_usage);
+
+                    if cpu_usage > 90.0 {
+                        warn!("High CPU usage detected: {:.1}%", cpu_usage);
+                    }
+                    if memory_usage > 90.0 {
+                        warn!("High memory usage detected: {:.1}%", memory_usage);
+                    }
+                }
+            }
+        }
+
+        Ok(())
+    }
+}
+
+/// A component that will fail after some time to demonstrate error handling.
+struct FailingComponent {
+    fail_after: Duration,
+}
+
+#[async_trait]
+impl Component for FailingComponent {
+    fn name(&self) -> Option<String> {
+        Some("failing-component".to_string())
+    }
+
+    async fn run(&self, cancellation: CancellationToken) -> Result<(), MadError> {
+        info!(
+            "Failing component started (will fail after {:?})",
+            self.fail_after
+        );
+
+        tokio::select! {
+            _ = cancellation.cancelled() => {
+                info!("Failing component cancelled before failure");
+                Ok(())
+            }
+            _ = tokio::time::sleep(self.fail_after) => {
+                error!("Failing component encountered an error!");
+                Err(anyhow::anyhow!("Simulated component failure").into())
+            }
+        }
+    }
+}
+
+/// Debug component that logs system status periodically.
+struct DebugComponent;
+
+#[async_trait]
+impl Component for DebugComponent {
+    fn name(&self) -> Option<String> {
+        Some("debug-component".to_string())
+    }
+
+    async fn run(&self, cancel: CancellationToken) -> Result<(), MadError> {
+        info!("Debug mode enabled - verbose logging active");
+        let mut interval = interval(Duration::from_secs(5));
+
+        while !cancel.is_cancelled() {
+            tokio::select! {
+                _ = cancel.cancelled() => break,
+                _ = interval.tick() => {
+                    info!("DEBUG: System running normally");
+                }
+            }
+        }
+
+        info!("Debug component shutting down");
+        Ok(())
+    }
+}
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    // Initialize tracing for logging
+    tracing_subscriber::fmt()
+        .with_target(false)
+        .without_time()
+        .init();
+
+    info!("Starting comprehensive MAD example application");
+
+    // Check if we should enable the failing component
+    let enable_failure_demo = std::env::var("ENABLE_FAILURE").is_ok();
+
+    // Check if we should enable debug mode
+    let debug_mode = std::env::var("DEBUG").is_ok();
+
+    // Shared state for demonstration
+    let request_count = Arc::new(AtomicUsize::new(0));
+
+    // Build and run the application
+    let result = Mad::builder()
+        // Add web servers
+        .add(WebServer {
+            port: 8080,
+            request_count: request_count.clone(),
+        })
+        .add(WebServer {
+            port: 8081,
+            request_count: request_count.clone(),
+        })
+        // Add job processors
+        .add(JobProcessor {
+            queue_name: "high-priority".to_string(),
+            processing_interval: Duration::from_secs(2),
+        })
+        .add(JobProcessor {
+            queue_name: "low-priority".to_string(),
+            processing_interval: Duration::from_secs(5),
+        })
+        // Add health checker
+        .add(HealthChecker {
+            check_interval: Duration::from_secs(3),
+        })
+        // Conditionally add a debug component using add_fn
+        .add_conditional(debug_mode, DebugComponent)
+        // Conditionally add failing component to demonstrate error handling
+        .add_conditional(
+            enable_failure_demo,
+            FailingComponent {
+                fail_after: Duration::from_secs(10),
+            },
+        )
+        // Add a simple metrics reporter using add_fn
+        .add_fn(|cancel: CancellationToken| async move {
+            info!("Metrics reporter started");
+            let mut interval = interval(Duration::from_secs(10));
+            let start = std::time::Instant::now();
+
+            while !cancel.is_cancelled() {
+                tokio::select! {
+                    _ = cancel.cancelled() => break,
+                    _ = interval.tick() => {
+                        let uptime = start.elapsed();
+                        info!("Application uptime: {:?}", uptime);
+                    }
+                }
+            }
+
+            info!("Metrics reporter stopped");
+            Ok(())
+        })
+        // Configure graceful shutdown timeout
+        .cancellation(Some(Duration::from_secs(5)))
+        // Run the application
+        .run()
+        .await;
+
+    match result {
+        Ok(()) => {
+            info!("Application shut down successfully");
+            Ok(())
+        }
+        Err(e) => {
+            error!("Application failed: {}", e);
+
+            // Check if it's an aggregate error with multiple failures
+            if let MadError::AggregateError(ref agg) = e {
+                error!("Multiple component failures detected:");
+                for (i, err) in agg.get_errors().iter().enumerate() {
+                    error!("  {}. {}", i + 1, err);
+                }
+            }
+
+            Err(e.into())
+        }
+    }
+}

crates/mad/examples/multi_service/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "mad-multi-service-example"
+version = "0.1.0"
+edition = "2021"
+
+[[bin]]
+name = "multi_service"
+path = "main.rs"
+
+[dependencies]
+notmad = { path = "../.." }
+tokio = { version = "1", features = ["full"] }
+tokio-util = "0.7"
+async-trait = "0.1"
+anyhow = "1"

crates/mad/examples/multi_service/main.rs

@@ -0,0 +1,214 @@
+//! Example demonstrating running multiple services with MAD.
+//!
+//! This example shows how to run a web server, queue processor, and
+//! scheduled task together, with graceful shutdown on Ctrl+C.
+
+use async_trait::async_trait;
+use notmad::{Component, Mad, MadError};
+use tokio::time::{Duration, interval};
+use tokio_util::sync::CancellationToken;
+
+/// A simple web server component.
+///
+/// In a real application, this would bind to a port and handle HTTP requests.
+/// Here we simulate it by periodically logging that we're "handling" requests.
+struct WebServer {
+    port: u16,
+}
+
+#[async_trait]
+impl Component for WebServer {
+    fn name(&self) -> Option<String> {
+        Some(format!("WebServer:{}", self.port))
+    }
+
+    async fn setup(&self) -> Result<(), MadError> {
+        println!("[{}] Binding to port...", self.name().unwrap());
+        // Simulate server setup time
+        tokio::time::sleep(Duration::from_millis(100)).await;
+        println!("[{}] Ready to accept connections", self.name().unwrap());
+        Ok(())
+    }
+
+    async fn run(&self, cancellation: CancellationToken) -> Result<(), MadError> {
+        println!("[{}] Server started", self.name().unwrap());
+
+        // Simulate handling requests until shutdown
+        let mut request_id = 0;
+        let mut interval = interval(Duration::from_secs(2));
+
+        while !cancellation.is_cancelled() {
+            tokio::select! {
+                _ = cancellation.cancelled() => {
+                    println!("[{}] Shutdown signal received", self.name().unwrap());
+                    break;
+                }
+                _ = interval.tick() => {
+                    request_id += 1;
+                    println!("[{}] Handling request #{}", self.name().unwrap(), request_id);
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    async fn close(&self) -> Result<(), MadError> {
+        println!("[{}] Closing connections...", self.name().unwrap());
+        // Simulate graceful connection drain
+        tokio::time::sleep(Duration::from_millis(200)).await;
+        println!("[{}] Server stopped", self.name().unwrap());
+        Ok(())
+    }
+}
+
+/// A queue processor that consumes messages from a queue.
+///
+/// This simulates processing messages from a message queue like
+/// RabbitMQ, Kafka, or AWS SQS.
+struct QueueProcessor {
+    queue_name: String,
+}
+
+#[async_trait]
+impl Component for QueueProcessor {
+    fn name(&self) -> Option<String> {
+        Some(format!("QueueProcessor:{}", self.queue_name))
+    }
+
+    async fn run(&self, cancellation: CancellationToken) -> Result<(), MadError> {
+        println!("[{}] Started processing", self.name().unwrap());
+
+        let mut message_count = 0;
+
+        // Process messages until shutdown
+        while !cancellation.is_cancelled() {
+            // Simulate waiting for and processing a message
+            tokio::select! {
+                _ = cancellation.cancelled() => {
+                    println!("[{}] Stopping message processing", self.name().unwrap());
+                    break;
+                }
+                _ = tokio::time::sleep(Duration::from_secs(1)) => {
+                    message_count += 1;
+                    println!("[{}] Processed message #{}", self.name().unwrap(), message_count);
+                }
+            }
+        }
+
+        println!(
+            "[{}] Processed {} messages total",
+            self.name().unwrap(),
+            message_count
+        );
+        Ok(())
+    }
+}
+
+/// A scheduled task that runs periodically.
+///
+/// This could be used for tasks like:
+/// - Cleaning up old data
+/// - Generating reports
+/// - Syncing with external systems
+struct ScheduledTask {
+    task_name: String,
+    interval_secs: u64,
+}
+
+#[async_trait]
+impl Component for ScheduledTask {
+    fn name(&self) -> Option<String> {
+        Some(format!("ScheduledTask:{}", self.task_name))
+    }
+
+    async fn run(&self, cancellation: CancellationToken) -> Result<(), MadError> {
+        println!(
+            "[{}] Scheduled to run every {} seconds",
+            self.name().unwrap(),
+            self.interval_secs
+        );
+
+        let mut interval = interval(Duration::from_secs(self.interval_secs));
+        let mut run_count = 0;
+
+        while !cancellation.is_cancelled() {
+            tokio::select! {
+                _ = cancellation.cancelled() => {
+                    println!("[{}] Scheduler stopping", self.name().unwrap());
+                    break;
+                }
+                _ = interval.tick() => {
+                    run_count += 1;
+                    println!("[{}] Executing run #{}", self.name().unwrap(), run_count);
+
+                    // Simulate task execution
+                    tokio::time::sleep(Duration::from_millis(500)).await;
+
+                    println!("[{}] Run #{} completed", self.name().unwrap(), run_count);
+                }
+            }
+        }
+
+        Ok(())
+    }
+}
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    println!("Starting multi-service application");
+    println!("Press Ctrl+C to trigger graceful shutdown");
+    println!("----------------------------------------");
+
+    // Build the application with multiple services
+    Mad::builder()
+        // Add a web server on port 8080
+        .add(WebServer { port: 8080 })
+        // Add another web server on port 8081 (e.g., admin interface)
+        .add(WebServer { port: 8081 })
+        // Add queue processors for different queues
+        .add(QueueProcessor {
+            queue_name: "orders".to_string(),
+        })
+        .add(QueueProcessor {
+            queue_name: "notifications".to_string(),
+        })
+        // Add scheduled tasks
+        .add(ScheduledTask {
+            task_name: "cleanup".to_string(),
+            interval_secs: 5,
+        })
+        .add(ScheduledTask {
+            task_name: "report_generator".to_string(),
+            interval_secs: 10,
+        })
+        // Add a monitoring component using a closure
+        .add_fn(|cancel| async move {
+            println!("[Monitor] Starting system monitor");
+            let mut interval = interval(Duration::from_secs(15));
+
+            while !cancel.is_cancelled() {
+                tokio::select! {
+                    _ = cancel.cancelled() => {
+                        println!("[Monitor] Stopping monitor");
+                        break;
+                    }
+                    _ = interval.tick() => {
+                        println!("[Monitor] All systems operational");
+                    }
+                }
+            }
+
+            Ok(())
+        })
+        // Set graceful shutdown timeout to 3 seconds
+        .cancellation(Some(Duration::from_secs(3)))
+        // Run all components
+        .run()
+        .await?;
+
+    println!("----------------------------------------");
+    println!("All services shut down successfully");
+
+    Ok(())
+}

crates/mad/examples/nested_errors/main.rs

@@ -0,0 +1,86 @@
+use async_trait::async_trait;
+use tokio_util::sync::CancellationToken;
+
+struct NestedErrorComponent {
+    name: String,
+}
+
+#[async_trait]
+impl notmad::Component for NestedErrorComponent {
+    fn name(&self) -> Option<String> {
+        Some(self.name.clone())
+    }
+
+    async fn run(&self, _cancellation: CancellationToken) -> Result<(), notmad::MadError> {
+        // Simulate a deeply nested error
+        let io_error = std::io::Error::new(
+            std::io::ErrorKind::PermissionDenied,
+            "access denied to /etc/secret",
+        );
+
+        Err(anyhow::Error::from(io_error)
+            .context("failed to read configuration file")
+            .context("unable to initialize database connection pool")
+            .context(format!("component '{}' startup failed", self.name))
+            .into())
+    }
+}
+
+struct AnotherFailingComponent;
+
+#[async_trait]
+impl notmad::Component for AnotherFailingComponent {
+    fn name(&self) -> Option<String> {
+        Some("another-component".into())
+    }
+
+    async fn run(&self, _cancellation: CancellationToken) -> Result<(), notmad::MadError> {
+        tokio::time::sleep(std::time::Duration::from_millis(100)).await;
+
+        Err(anyhow::anyhow!("network timeout after 30s")
+            .context("failed to connect to external API")
+            .context("service health check failed")
+            .into())
+    }
+}
+
+#[tokio::main]
+async fn main() {
+    tracing_subscriber::fmt()
+        .with_env_filter("mad=debug")
+        .init();
+
+    let result = notmad::Mad::builder()
+        .add(NestedErrorComponent {
+            name: "database-service".into(),
+        })
+        .add(AnotherFailingComponent)
+        .run()
+        .await;
+
+    match result {
+        Ok(()) => println!("Success!"),
+        Err(e) => {
+            eprintln!("\n=== Error occurred ===");
+            eprintln!("{}", e);
+
+            // Also demonstrate how to walk the error chain manually
+            if let notmad::MadError::AggregateError(ref agg) = e {
+                eprintln!("\n=== Detailed error chains ===");
+                for (i, error) in agg.get_errors().iter().enumerate() {
+                    eprintln!("\nComponent {} error chain:", i + 1);
+                    if let notmad::MadError::Inner(inner) = error {
+                        for (j, cause) in inner.chain().enumerate() {
+                            eprintln!("  {}. {}", j + 1, cause);
+                        }
+                    }
+                }
+            } else if let notmad::MadError::Inner(ref inner) = e {
+                eprintln!("\n=== Error chain ===");
+                for (i, cause) in inner.chain().enumerate() {
+                    eprintln!("  {}. {}", i + 1, cause);
+                }
+            }
+        }
+    }
+}

crates/mad/src/lib.rs

@@ -1,6 +1,83 @@
+//! # MAD - Lifecycle Manager for Rust Applications
+//!
+//! MAD is a robust lifecycle manager designed for long-running Rust operations. It provides
+//! a simple, composable way to manage multiple concurrent services within your application,
+//! handling graceful startup and shutdown automatically.
+//!
+//! ## Overview
+//!
+//! MAD helps you build applications composed of multiple long-running components that need
+//! to be orchestrated together. It handles:
+//!
+//! - **Concurrent execution** of multiple components
+//! - **Graceful shutdown** with cancellation tokens
+//! - **Error aggregation** from multiple components
+//! - **Lifecycle management** with setup, run, and close phases
+//!
+//! ## Quick Start
+//!
+//! ```rust,no_run
+//! use notmad::{Component, Mad};
+//! use async_trait::async_trait;
+//! use tokio_util::sync::CancellationToken;
+//!
+//! struct MyService {
+//!     name: String,
+//! }
+//!
+//! #[async_trait]
+//! impl Component for MyService {
+//!     fn name(&self) -> Option<String> {
+//!         Some(self.name.clone())
+//!     }
+//!
+//!     async fn run(&self, cancellation: CancellationToken) -> Result<(), notmad::MadError> {
+//!         // Your service logic here
+//!         while !cancellation.is_cancelled() {
+//!             // Do work...
+//!             tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+//!         }
+//!         Ok(())
+//!     }
+//! }
+//!
+//! #[tokio::main]
+//! async fn main() -> anyhow::Result<()> {
+//!     Mad::builder()
+//!         .add(MyService { name: "service-1".into() })
+//!         .add(MyService { name: "service-2".into() })
+//!         .run()
+//!         .await?;
+//!     Ok(())
+//! }
+//! ```
+//!
+//! ## Component Lifecycle
+//!
+//! Components go through three phases:
+//!
+//! 1. **Setup**: Optional initialization phase before components start running
+//! 2. **Run**: Main execution phase where components perform their work
+//! 3. **Close**: Optional cleanup phase after components stop
+//!
+//! ## Error Handling
+//!
+//! MAD provides comprehensive error handling through [`MadError`], which can:
+//! - Wrap errors from individual components
+//! - Aggregate multiple errors when several components fail
+//! - Automatically convert from `anyhow::Error`
+//!
+//! ## Shutdown Behavior
+//!
+//! MAD handles shutdown gracefully:
+//! - Responds to SIGTERM and Ctrl+C signals
+//! - Propagates cancellation tokens to all components
+//! - Waits for components to finish cleanup
+//! - Configurable cancellation timeout
+
 use futures::stream::FuturesUnordered;
 use futures_util::StreamExt;
-use std::{fmt::Display, sync::Arc};
+use std::{fmt::Display, sync::Arc, error::Error};
 use tokio::signal::unix::{SignalKind, signal};
 
 use tokio_util::sync::CancellationToken;
@@ -9,23 +86,48 @@ use crate::waiter::Waiter;
 
 mod waiter;
 
+/// Error type for MAD operations.
+///
+/// This enum represents all possible errors that can occur during
+/// the lifecycle of MAD components.
 #[derive(thiserror::Error, Debug)]
 pub enum MadError {
-    #[error("component failed: {0}")]
+    /// Generic error wrapper for anyhow errors.
-    Inner(#[source] anyhow::Error),
+    ///
+    /// This variant is used when components return errors via the `?` operator
+    /// or when converting from `anyhow::Error`.
+    #[error(transparent)]
+    Inner(anyhow::Error),
 
-    #[error("component(s) failed: {run}")]
+    /// Error that occurred during the run phase of a component.
-    RunError { run: anyhow::Error },
+    #[error(transparent)]
+    RunError { 
+        run: anyhow::Error 
+    },
 
-    #[error("component(s) failed: {close}")]
+    /// Error that occurred during the close phase of a component.
-    CloseError { close: anyhow::Error },
+    #[error("component(s) failed during close")]
+    CloseError { 
+        #[source]
+        close: anyhow::Error 
+    },
 
-    #[error("component(s) failed: {0}")]
+    /// Multiple errors from different components.
+    ///
+    /// This is used when multiple components fail simultaneously,
+    /// allowing all errors to be reported rather than just the first one.
+    #[error("{0}")]
     AggregateError(AggregateError),
 
+    /// Returned when a component doesn't implement the optional setup method.
+    ///
+    /// This is not typically an error condition as setup is optional.
     #[error("setup not defined")]
     SetupNotDefined,
 
+    /// Returned when a component doesn't implement the optional close method.
+    ///
+    /// This is not typically an error condition as close is optional.
     #[error("close not defined")]
     CloseNotDefined,
 }
@@ -36,12 +138,30 @@ impl From<anyhow::Error> for MadError {
     }
 }
 
-#[derive(Debug)]
+/// Container for multiple errors from different components.
+///
+/// When multiple components fail, their errors are collected
+/// into this struct to provide complete error reporting.
+#[derive(Debug, thiserror::Error)]
 pub struct AggregateError {
     errors: Vec<MadError>,
 }
 
 impl AggregateError {
+    /// Returns a slice of all contained errors.
+    ///
+    /// # Example
+    ///
+    /// ```rust,ignore
+    /// match result {
+    ///     Err(notmad::MadError::AggregateError(agg)) => {
+    ///         for error in agg.get_errors() {
+    ///             eprintln!("Component error: {}", error);
+    ///         }
+    ///     }
+    ///     _ => {}
+    /// }
+    /// ```
     pub fn get_errors(&self) -> &[MadError] {
         &self.errors
     }
@@ -49,17 +169,60 @@ impl AggregateError {
 
 impl Display for AggregateError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str("MadError::AggregateError: (")?;
+        if self.errors.is_empty() {
-
+            return Ok(());
-        for error in &self.errors {
-            f.write_str(&error.to_string())?;
-            f.write_str(", ")?;
         }
 
-        f.write_str(")")
+        if self.errors.len() == 1 {
+            return write!(f, "{}", self.errors[0]);
+        }
+
+        writeln!(f, "{} component errors occurred:", self.errors.len())?;
+        for (i, error) in self.errors.iter().enumerate() {
+            write!(f, "\n[Component {}] {}", i + 1, error)?;
+            
+            // Print the error chain for each component error
+            let mut source = error.source();
+            let mut level = 1;
+            while let Some(err) = source {
+                write!(f, "\n  {}. {}", level, err)?;
+                source = err.source();
+                level += 1;
+            }
+        }
+        Ok(())
     }
 }
 
+/// The main lifecycle manager for running multiple components.
+///
+/// `Mad` orchestrates the lifecycle of multiple components, ensuring they
+/// start up in order, run concurrently, and shut down gracefully.
+///
+/// # Example
+///
+/// ```rust
+/// use notmad::{Component, Mad};
+/// use async_trait::async_trait;
+/// use tokio_util::sync::CancellationToken;
+///
+/// struct MyComponent;
+///
+/// #[async_trait]
+/// impl Component for MyComponent {
+///     async fn run(&self, _cancel: CancellationToken) -> Result<(), notmad::MadError> {
+///         Ok(())
+///     }
+/// }
+///
+/// # async fn example() -> Result<(), notmad::MadError> {
+/// Mad::builder()
+///     .add(MyComponent)
+///     .run()
+///     .await?;
+/// # Ok(())
+/// # }
+/// ```
 pub struct Mad {
     components: Vec<Arc<dyn Component + Send + Sync + 'static>>,
 
@@ -72,6 +235,18 @@ struct CompletionResult {
 }
 
 impl Mad {
+    /// Creates a new `Mad` builder.
+    ///
+    /// This is the entry point for constructing a MAD application.
+    /// Components are added using the builder pattern before calling `run()`.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use notmad::Mad;
+    ///
+    /// let mut app = Mad::builder();
+    /// ```
     pub fn builder() -> Self {
         Self {
             components: Vec::default(),
@@ -80,12 +255,65 @@ impl Mad {
         }
     }
 
+    /// Adds a component to the MAD application.
+    ///
+    /// Components will be set up in the order they are added,
+    /// run concurrently, and closed in the order they were added.
+    ///
+    /// # Arguments
+    ///
+    /// * `component` - Any type that implements `Component` or `IntoComponent`
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use notmad::{Component, Mad};
+    /// # use async_trait::async_trait;
+    /// # use tokio_util::sync::CancellationToken;
+    /// # struct MyService;
+    /// # #[async_trait]
+    /// # impl Component for MyService {
+    /// #     async fn run(&self, _: CancellationToken) -> Result<(), notmad::MadError> { Ok(()) }
+    /// # }
+    ///
+    /// Mad::builder()
+    ///     .add(MyService)
+    ///     .add(MyService);
+    /// ```
     pub fn add(&mut self, component: impl IntoComponent) -> &mut Self {
         self.components.push(component.into_component());
 
         self
     }
 
+    /// Conditionally adds a component based on a boolean condition.
+    ///
+    /// If the condition is false, a waiter component is added instead,
+    /// which simply waits for cancellation without doing any work.
+    ///
+    /// # Arguments
+    ///
+    /// * `condition` - If true, adds the component; if false, adds a waiter
+    /// * `component` - The component to add if condition is true
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use notmad::Mad;
+    /// # use notmad::Component;
+    /// # use async_trait::async_trait;
+    /// # use tokio_util::sync::CancellationToken;
+    /// # struct DebugService;
+    /// # #[async_trait]
+    /// # impl Component for DebugService {
+    /// #     async fn run(&self, _: CancellationToken) -> Result<(), notmad::MadError> { Ok(()) }
+    /// # }
+    ///
+    /// let enable_debug = std::env::var("DEBUG").is_ok();
+    ///
+    /// Mad::builder()
+    ///     .add_conditional(enable_debug, DebugService);
+    /// ```
     pub fn add_conditional(&mut self, condition: bool, component: impl IntoComponent) -> &mut Self {
         if condition {
             self.components.push(component.into_component());
@@ -97,12 +325,53 @@ impl Mad {
         self
     }
 
+    /// Adds a waiter component that does nothing but wait for cancellation.
+    ///
+    /// This is useful when you need a placeholder component or want
+    /// the application to keep running without any specific work.
+    ///
+    /// # Example
+    ///
+    /// ```rust,no_run
+    /// # async fn example() {
+    /// use notmad::Mad;
+    ///
+    /// Mad::builder()
+    ///     .add_wait()  // Keeps the app running until shutdown signal
+    ///     .run()
+    ///     .await;
+    /// # }
+    /// ```
     pub fn add_wait(&mut self) -> &mut Self {
         self.components.push(Waiter::default().into_component());
 
         self
     }
 
+    /// Adds a closure or function as a component.
+    ///
+    /// This is a convenient way to add simple components without
+    /// creating a full struct that implements `Component`.
+    ///
+    /// # Arguments
+    ///
+    /// * `f` - A closure that takes a `CancellationToken` and returns a future
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use notmad::Mad;
+    /// use tokio_util::sync::CancellationToken;
+    ///
+    /// Mad::builder()
+    ///     .add_fn(|cancel: CancellationToken| async move {
+    ///         while !cancel.is_cancelled() {
+    ///             println!("Working...");
+    ///             tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+    ///         }
+    ///         Ok(())
+    ///     });
+    /// ```
     pub fn add_fn<F, Fut>(&mut self, f: F) -> &mut Self
     where
         F: Fn(CancellationToken) -> Fut + Send + Sync + 'static,
@@ -113,12 +382,63 @@ impl Mad {
         self.add(comp)
     }
 
+    /// Configures the cancellation timeout behavior.
+    ///
+    /// When a shutdown signal is received, MAD will:
+    /// 1. Send cancellation tokens to all components
+    /// 2. Wait for the specified duration
+    /// 3. Force shutdown if components haven't stopped
+    ///
+    /// # Arguments
+    ///
+    /// * `should_cancel` - Duration to wait after cancellation before forcing shutdown.
+    ///                     Pass `None` to wait indefinitely.
+    ///
+    /// # Example
+    ///
+    /// ```rust,no_run
+    /// # async fn example() {
+    /// use notmad::Mad;
+    /// use std::time::Duration;
+    ///
+    /// Mad::builder()
+    ///     .cancellation(Some(Duration::from_secs(30)))  // 30 second grace period
+    ///     .run()
+    ///     .await;
+    /// # }
+    /// ```
     pub fn cancellation(&mut self, should_cancel: Option<std::time::Duration>) -> &mut Self {
         self.should_cancel = should_cancel;
 
         self
     }
 
+    /// Runs all components until completion or shutdown.
+    ///
+    /// This method:
+    /// 1. Calls `setup()` on all components (in order)
+    /// 2. Starts all components concurrently
+    /// 3. Waits for shutdown signal (SIGTERM, Ctrl+C) or component failure
+    /// 4. Sends cancellation to all components
+    /// 5. Calls `close()` on all components (in order)
+    ///
+    /// # Returns
+    ///
+    /// * `Ok(())` if all components shut down cleanly
+    /// * `Err(MadError)` if any component fails
+    ///
+    /// # Example
+    ///
+    /// ```rust,no_run
+    /// # use notmad::Mad;
+    /// # async fn example() -> Result<(), notmad::MadError> {
+    /// Mad::builder()
+    ///     .add_wait()
+    ///     .run()
+    ///     .await?;
+    /// # Ok(())
+    /// # }
+    /// ```
     pub async fn run(&mut self) -> Result<(), MadError> {
         tracing::info!("running mad setup");
 
@@ -281,24 +601,148 @@ async fn signal_unix_terminate() {
     sigterm.recv().await;
 }
 
+/// Trait for implementing MAD components.
+///
+/// Components represent individual services or tasks that run as part
+/// of your application. Each component has its own lifecycle with
+/// optional setup and cleanup phases.
+///
+/// # Example
+///
+/// ```rust
+/// use notmad::{Component, MadError};
+/// use async_trait::async_trait;
+/// use tokio_util::sync::CancellationToken;
+///
+/// struct DatabaseConnection {
+///     url: String,
+/// }
+///
+/// #[async_trait]
+/// impl Component for DatabaseConnection {
+///     fn name(&self) -> Option<String> {
+///         Some("database".to_string())
+///     }
+///
+///     async fn setup(&self) -> Result<(), MadError> {
+///         println!("Connecting to database...");
+///         // Initialize connection pool
+///         Ok(())
+///     }
+///
+///     async fn run(&self, cancel: CancellationToken) -> Result<(), MadError> {
+///         // Keep connection alive, handle queries
+///         cancel.cancelled().await;
+///         Ok(())
+///     }
+///
+///     async fn close(&self) -> Result<(), MadError> {
+///         println!("Closing database connection...");
+///         // Clean up resources
+///         Ok(())
+///     }
+/// }
+/// ```
 #[async_trait::async_trait]
 pub trait Component {
+    /// Returns an optional name for the component.
+    ///
+    /// This name is used in logging and error messages to identify
+    /// which component is being processed.
+    ///
+    /// # Default
+    ///
+    /// Returns `None` if not overridden.
     fn name(&self) -> Option<String> {
         None
     }
 
+    /// Optional setup phase called before the component starts running.
+    ///
+    /// Use this for initialization tasks like:
+    /// - Establishing database connections
+    /// - Loading configuration
+    /// - Preparing resources
+    ///
+    /// # Default
+    ///
+    /// Returns `MadError::SetupNotDefined` which is handled gracefully.
+    ///
+    /// # Errors
+    ///
+    /// If setup fails with an error other than `SetupNotDefined`,
+    /// the entire application will stop before any components start running.
     async fn setup(&self) -> Result<(), MadError> {
         Err(MadError::SetupNotDefined)
     }
 
+    /// Main execution phase of the component.
+    ///
+    /// This method should contain the primary logic of your component.
+    /// It should respect the cancellation token and shut down gracefully
+    /// when cancellation is requested.
+    ///
+    /// # Arguments
+    ///
+    /// * `cancellation_token` - Signal for graceful shutdown
+    ///
+    /// # Implementation Guidelines
+    ///
+    /// - Check `cancellation_token.is_cancelled()` periodically
+    /// - Use `tokio::select!` with `cancellation_token.cancelled()` for async operations
+    /// - Clean up resources before returning
+    ///
+    /// # Errors
+    ///
+    /// Any error returned will trigger shutdown of all other components.
     async fn run(&self, cancellation_token: CancellationToken) -> Result<(), MadError>;
 
+    /// Optional cleanup phase called after the component stops.
+    ///
+    /// Use this for cleanup tasks like:
+    /// - Flushing buffers
+    /// - Closing connections
+    /// - Saving state
+    ///
+    /// # Default
+    ///
+    /// Returns `MadError::CloseNotDefined` which is handled gracefully.
+    ///
+    /// # Errors
+    ///
+    /// Errors during close are logged but don't prevent other components
+    /// from closing.
     async fn close(&self) -> Result<(), MadError> {
         Err(MadError::CloseNotDefined)
     }
 }
 
+/// Trait for converting types into components.
+///
+/// This trait is automatically implemented for all types that implement
+/// `Component + Send + Sync + 'static`, allowing them to be added to MAD
+/// directly without manual conversion.
+///
+/// # Example
+///
+/// ```rust
+/// use notmad::{Component, IntoComponent, Mad};
+/// # use async_trait::async_trait;
+/// # use tokio_util::sync::CancellationToken;
+///
+/// struct MyService;
+///
+/// # #[async_trait]
+/// # impl Component for MyService {
+/// #     async fn run(&self, _: CancellationToken) -> Result<(), notmad::MadError> { Ok(()) }
+/// # }
+///
+/// // MyService automatically implements IntoComponent
+/// Mad::builder()
+///     .add(MyService);  // Works directly
+/// ```
 pub trait IntoComponent {
+    /// Converts self into an Arc-wrapped component.
     fn into_component(self) -> Arc<dyn Component + Send + Sync + 'static>;
 }
 
@@ -338,3 +782,132 @@ where
         self.execute(cancellation_token).await
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use anyhow::Context;
+
+    #[test]
+    fn test_error_chaining_display() {
+        // Test single error with context chain
+        let base_error = std::io::Error::new(std::io::ErrorKind::NotFound, "file not found");
+        let error = anyhow::Error::from(base_error)
+            .context("failed to read configuration")
+            .context("unable to initialize database")
+            .context("service startup failed");
+        
+        let mad_error = MadError::Inner(error);
+        let display = format!("{}", mad_error);
+        
+        // Should display the top-level error message
+        assert!(display.contains("service startup failed"));
+        
+        // Test error chain iteration
+        if let MadError::Inner(ref e) = mad_error {
+            let chain: Vec<String> = e.chain().map(|c| c.to_string()).collect();
+            assert_eq!(chain.len(), 4);
+            assert_eq!(chain[0], "service startup failed");
+            assert_eq!(chain[1], "unable to initialize database");
+            assert_eq!(chain[2], "failed to read configuration");
+            assert_eq!(chain[3], "file not found");
+        }
+    }
+
+    #[test]
+    fn test_aggregate_error_display() {
+        let error1 = MadError::Inner(
+            anyhow::anyhow!("database connection failed")
+                .context("failed to connect to PostgreSQL")
+        );
+        
+        let error2 = MadError::Inner(
+            anyhow::anyhow!("port already in use")
+                .context("failed to bind to port 8080")
+                .context("web server initialization failed")
+        );
+        
+        let aggregate = MadError::AggregateError(AggregateError {
+            errors: vec![error1, error2],
+        });
+        
+        let display = format!("{}", aggregate);
+        
+        // Check that it shows multiple errors
+        assert!(display.contains("2 component errors occurred"));
+        assert!(display.contains("[Component 1]"));
+        assert!(display.contains("[Component 2]"));
+        
+        // Check that context chains are displayed
+        assert!(display.contains("failed to connect to PostgreSQL"));
+        assert!(display.contains("database connection failed"));
+        assert!(display.contains("web server initialization failed"));
+        assert!(display.contains("failed to bind to port 8080"));
+        assert!(display.contains("port already in use"));
+    }
+
+    #[test]
+    fn test_single_error_aggregate() {
+        let error = MadError::Inner(anyhow::anyhow!("single error"));
+        let aggregate = AggregateError {
+            errors: vec![error],
+        };
+        
+        let display = format!("{}", aggregate);
+        // Single error should be displayed directly
+        assert!(display.contains("single error"));
+        assert!(!display.contains("component errors occurred"));
+    }
+
+    #[test]
+    fn test_error_source_chain() {
+        let error = MadError::Inner(
+            anyhow::anyhow!("root cause")
+                .context("middle layer")
+                .context("top layer")
+        );
+        
+        // Test that we can access the error chain
+        if let MadError::Inner(ref e) = error {
+            let chain: Vec<String> = e.chain().map(|c| c.to_string()).collect();
+            assert_eq!(chain.len(), 3);
+            assert_eq!(chain[0], "top layer");
+            assert_eq!(chain[1], "middle layer");
+            assert_eq!(chain[2], "root cause");
+        } else {
+            panic!("Expected MadError::Inner");
+        }
+    }
+
+    #[tokio::test]
+    async fn test_component_error_propagation() {
+        struct FailingComponent;
+        
+        #[async_trait::async_trait]
+        impl Component for FailingComponent {
+            fn name(&self) -> Option<String> {
+                Some("test-component".to_string())
+            }
+            
+            async fn run(&self, _cancel: CancellationToken) -> Result<(), MadError> {
+                Err(anyhow::anyhow!("IO error")
+                    .context("failed to open file")
+                    .context("component initialization failed")
+                    .into())
+            }
+        }
+        
+        let result = Mad::builder()
+            .add(FailingComponent)
+            .cancellation(Some(std::time::Duration::from_millis(100)))
+            .run()
+            .await;
+        
+        assert!(result.is_err());
+        let error = result.unwrap_err();
+        
+        // Check error display
+        let display = format!("{}", error);
+        assert!(display.contains("component initialization failed"));
+    }
+}

crates/mad/src/waiter.rs

@@ -1,3 +1,9 @@
+//! Waiter components for MAD.
+//!
+//! This module provides waiter components that simply wait for cancellation
+//! without performing any work. Useful for keeping the application alive
+//! or as placeholders in conditional component loading.
+
 use std::sync::Arc;
 
 use async_trait::async_trait;
@@ -5,6 +11,10 @@ use tokio_util::sync::CancellationToken;
 
 use crate::{Component, MadError};
 
+/// A default waiter component that panics if run.
+///
+/// This is used internally as a placeholder that should never
+/// actually be executed.
 pub struct DefaultWaiter {}
 #[async_trait]
 impl Component for DefaultWaiter {
@@ -13,6 +23,20 @@ impl Component for DefaultWaiter {
     }
 }
 
+/// A wrapper component that waits for cancellation.
+///
+/// Instead of running the wrapped component's logic, this simply
+/// waits for the cancellation token. This is useful for conditionally
+/// disabling components while keeping the same structure.
+///
+/// # Example
+///
+/// ```rust,ignore
+/// use mad::Waiter;
+///
+/// // Instead of running the service, just wait
+/// let waiter = Waiter::new(service.into_component());
+/// ```
 pub struct Waiter {
     comp: Arc<dyn Component + Send + Sync + 'static>,
 }
@@ -26,6 +50,10 @@ impl Default for Waiter {
 }
 
 impl Waiter {
+    /// Creates a new waiter that wraps the given component.
+    ///
+    /// The wrapped component's name will be used (prefixed with "waiter/"),
+    /// but its run method will not be called.
     pub fn new(c: Arc<dyn Component + Send + Sync + 'static>) -> Self {
         Self { comp: c }
     }
@@ -33,6 +61,10 @@ impl Waiter {
 
 #[async_trait]
 impl Component for Waiter {
+    /// Returns the name of the waiter, prefixed with "waiter/".
+    ///
+    /// If the wrapped component has a name, it will be "waiter/{name}".
+    /// Otherwise, returns "waiter".
     fn name(&self) -> Option<String> {
         match self.comp.name() {
             Some(name) => Some(format!("waiter/{name}")),
@@ -40,6 +72,10 @@ impl Component for Waiter {
         }
     }
 
+    /// Waits for cancellation without performing any work.
+    ///
+    /// This method simply waits for the cancellation token to be triggered,
+    /// then returns successfully.
     async fn run(&self, cancellation_token: CancellationToken) -> Result<(), MadError> {
         cancellation_token.cancelled().await;
 

cuddle.yaml

@@ -1,6 +1,6 @@
-# yaml-language-server: $schema=https://git.front.kjuulh.io/kjuulh/cuddle/raw/branch/main/schemas/base.json
+# yaml-language-server: $schema=https://git.kjuulh.io/kjuulh/cuddle/raw/branch/main/schemas/base.json
 
-base: "git@git.front.kjuulh.io:kjuulh/cuddle-rust-lib-plan.git"
+base: "git@git.kjuulh.io:kjuulh/cuddle-rust-lib-plan.git"
 
 vars:
   service: "mad"
@@ -12,6 +12,6 @@ please:
     repository: "mad"
     branch: main
   settings:
-    api_url: "https://git.front.kjuulh.io"
+    api_url: "https://git.kjuulh.io"
   actions:
     rust: