IoT Domain
Layer 3: Domain Constraints
Domain Constraints → Design Implications
| Domain Rule |
Design Constraint |
Rust Implication |
| Unreliable network |
Offline-first |
Local buffering |
| Power constraints |
Efficient code |
Sleep modes, minimal alloc |
| Resource limits |
Small footprint |
no_std where needed |
| Security |
Encrypted comms |
TLS, signed firmware |
| Reliability |
Self-recovery |
Watchdog, error handling |
| OTA updates |
Safe upgrades |
Rollback capability |
Critical Constraints
Network Unreliability
RULE: Network can fail at any time
WHY: Wireless, remote locations
RUST: Local queue, retry with backoff
Power Management
RULE: Minimize power consumption
WHY: Battery life, energy costs
RUST: Sleep modes, efficient algorithms
Device Security
RULE: All communication encrypted
WHY: Physical access possible
RUST: TLS, signed messages
Trace Down ↓
From constraints to design (Layer 2):
"Need offline-first design"
↓ m12-lifecycle: Local buffer with persistence
↓ m13-domain-error: Retry with backoff
"Need power efficiency"
↓ domain-embedded: no_std patterns
↓ m10-performance: Minimal allocations
"Need reliable messaging"
↓ m07-concurrency: Async with timeout
↓ MQTT: QoS levels
Environment Comparison
| Environment |
Stack |
Crates |
| Linux gateway |
tokio + std |
rumqttc, reqwest |
| MCU device |
embassy + no_std |
embedded-hal |
| Hybrid |
Split workloads |
Both |
Key Crates
| Purpose |
Crate |
| MQTT (std) |
rumqttc, paho-mqtt |
| Embedded |
embedded-hal, embassy |
| Async (std) |
tokio |
| Async (no_std) |
embassy |
| Logging (no_std) |
defmt |
| Logging (std) |
tracing |
Design Patterns
| Pattern |
Purpose |
Implementation |
| Pub/Sub |
Device comms |
MQTT topics |
| Edge compute |
Local processing |
Filter before upload |
| OTA updates |
Firmware upgrade |
Signed + rollback |
| Power mgmt |
Battery life |
Sleep + wake events |
| Store & forward |
Network reliability |
Local queue |
Code Pattern: MQTT Client
use rumqttc::{AsyncClient, MqttOptions, QoS};
async fn run_mqtt() -> anyhow::Result<()> {
let mut options = MqttOptions::new("device-1", "broker.example.com", 1883);
options.set_keep_alive(Duration::from_secs(30));
let (client, mut eventloop) = AsyncClient::new(options, 10);
// Subscribe to commands
client.subscribe("devices/device-1/commands", QoS::AtLeastOnce).await?;
// Publish telemetry
tokio::spawn(async move {
loop {
let data = read_sensor().await;
client.publish("devices/device-1/telemetry", QoS::AtLeastOnce, false, data).await.ok();
tokio::time::sleep(Duration::from_secs(60)).await;
}
});
// Process events
loop {
match eventloop.poll().await {
Ok(event) => handle_event(event).await,
Err(e) => {
tracing::error!("MQTT error: {}", e);
tokio::time::sleep(Duration::from_secs(5)).await;
}
}
}
}
Common Mistakes
| Mistake |
Domain Violation |
Fix |
| No retry logic |
Lost data |
Exponential backoff |
| Always-on radio |
Battery drain |
Sleep between sends |
| Unencrypted MQTT |
Security risk |
TLS |
| No local buffer |
Network outage = data loss |
Persist locally |
Trace to Layer 1
| Constraint |
Layer 2 Pattern |
Layer 1 Implementation |
| Offline-first |
Store & forward |
Local queue + flush |
| Power efficiency |
Sleep patterns |
Timer-based wake |
| Network reliability |
Retry |
tokio-retry, backoff |
| Security |
TLS |
rustls, native-tls |
Related Skills
| When |
See |
| Embedded patterns |
domain-embedded |
| Async patterns |
m07-concurrency |
| Error recovery |
m13-domain-error |
| Performance |
m10-performance |
1---2name: domain-iot3description: "Use when building IoT apps. Keywords: IoT, Internet of Things, sensor, MQTT, device, edge computing, telemetry, actuator, smart home, gateway, protocol, 物联网, 传感器, 边缘计算, 智能家居"4user-invocable: false5---67# IoT Domain89> **Layer 3: Domain Constraints**1011## Domain Constraints → Design Implications1213| Domain Rule | Design Constraint | Rust Implication |14|-------------|-------------------|------------------|15| Unreliable network | Offline-first | Local buffering |16| Power constraints | Efficient code | Sleep modes, minimal alloc |17| Resource limits | Small footprint | no_std where needed |18| Security | Encrypted comms | TLS, signed firmware |19| Reliability | Self-recovery | Watchdog, error handling |20| OTA updates | Safe upgrades | Rollback capability |2122---2324## Critical Constraints2526### Network Unreliability2728```29RULE: Network can fail at any time30WHY: Wireless, remote locations31RUST: Local queue, retry with backoff32```3334### Power Management3536```37RULE: Minimize power consumption38WHY: Battery life, energy costs39RUST: Sleep modes, efficient algorithms40```4142### Device Security4344```45RULE: All communication encrypted46WHY: Physical access possible47RUST: TLS, signed messages48```4950---5152## Trace Down ↓5354From constraints to design (Layer 2):5556```57"Need offline-first design"58 ↓ m12-lifecycle: Local buffer with persistence59 ↓ m13-domain-error: Retry with backoff6061"Need power efficiency"62 ↓ domain-embedded: no_std patterns63 ↓ m10-performance: Minimal allocations6465"Need reliable messaging"66 ↓ m07-concurrency: Async with timeout67 ↓ MQTT: QoS levels68```6970---7172## Environment Comparison7374| Environment | Stack | Crates |75|-------------|-------|--------|76| Linux gateway | tokio + std | rumqttc, reqwest |77| MCU device | embassy + no_std | embedded-hal |78| Hybrid | Split workloads | Both |7980## Key Crates8182| Purpose | Crate |83|---------|-------|84| MQTT (std) | rumqttc, paho-mqtt |85| Embedded | embedded-hal, embassy |86| Async (std) | tokio |87| Async (no_std) | embassy |88| Logging (no_std) | defmt |89| Logging (std) | tracing |9091## Design Patterns9293| Pattern | Purpose | Implementation |94|---------|---------|----------------|95| Pub/Sub | Device comms | MQTT topics |96| Edge compute | Local processing | Filter before upload |97| OTA updates | Firmware upgrade | Signed + rollback |98| Power mgmt | Battery life | Sleep + wake events |99| Store & forward | Network reliability | Local queue |100101## Code Pattern: MQTT Client102103```rust104use rumqttc::{AsyncClient, MqttOptions, QoS};105106async fn run_mqtt() -> anyhow::Result<()> {107 let mut options = MqttOptions::new("device-1", "broker.example.com", 1883);108 options.set_keep_alive(Duration::from_secs(30));109110 let (client, mut eventloop) = AsyncClient::new(options, 10);111112 // Subscribe to commands113 client.subscribe("devices/device-1/commands", QoS::AtLeastOnce).await?;114115 // Publish telemetry116 tokio::spawn(async move {117 loop {118 let data = read_sensor().await;119 client.publish("devices/device-1/telemetry", QoS::AtLeastOnce, false, data).await.ok();120 tokio::time::sleep(Duration::from_secs(60)).await;121 }122 });123124 // Process events125 loop {126 match eventloop.poll().await {127 Ok(event) => handle_event(event).await,128 Err(e) => {129 tracing::error!("MQTT error: {}", e);130 tokio::time::sleep(Duration::from_secs(5)).await;131 }132 }133 }134}135```136137---138139## Common Mistakes140141| Mistake | Domain Violation | Fix |142|---------|-----------------|-----|143| No retry logic | Lost data | Exponential backoff |144| Always-on radio | Battery drain | Sleep between sends |145| Unencrypted MQTT | Security risk | TLS |146| No local buffer | Network outage = data loss | Persist locally |147148---149150## Trace to Layer 1151152| Constraint | Layer 2 Pattern | Layer 1 Implementation |153|------------|-----------------|------------------------|154| Offline-first | Store & forward | Local queue + flush |155| Power efficiency | Sleep patterns | Timer-based wake |156| Network reliability | Retry | tokio-retry, backoff |157| Security | TLS | rustls, native-tls |158159---160161## Related Skills162163| When | See |164|------|-----|165| Embedded patterns | domain-embedded |166| Async patterns | m07-concurrency |167| Error recovery | m13-domain-error |168| Performance | m10-performance |
0xharryriddle