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4---56# IoT Domain78> **Layer 3: Domain Constraints**910## Domain Constraints → Design Implications1112| Domain Rule | Design Constraint | Rust Implication |13|-------------|-------------------|------------------|14| Unreliable network | Offline-first | Local buffering |15| Power constraints | Efficient code | Sleep modes, minimal alloc |16| Resource limits | Small footprint | no_std where needed |17| Security | Encrypted comms | TLS, signed firmware |18| Reliability | Self-recovery | Watchdog, error handling |19| OTA updates | Safe upgrades | Rollback capability |2021---2223## Critical Constraints2425### Network Unreliability2627```28RULE: Network can fail at any time29WHY: Wireless, remote locations30RUST: Local queue, retry with backoff31```3233### Power Management3435```36RULE: Minimize power consumption37WHY: Battery life, energy costs38RUST: Sleep modes, efficient algorithms39```4041### Device Security4243```44RULE: All communication encrypted45WHY: Physical access possible46RUST: TLS, signed messages47```4849---5051## Trace Down ↓5253From constraints to design (Layer 2):5455```56"Need offline-first design"57 ↓ m12-lifecycle: Local buffer with persistence58 ↓ m13-domain-error: Retry with backoff5960"Need power efficiency"61 ↓ domain-embedded: no_std patterns62 ↓ m10-performance: Minimal allocations6364"Need reliable messaging"65 ↓ m07-concurrency: Async with timeout66 ↓ MQTT: QoS levels67```6869---7071## Environment Comparison7273| Environment | Stack | Crates |74|-------------|-------|--------|75| Linux gateway | tokio + std | rumqttc, reqwest |76| MCU device | embassy + no_std | embedded-hal |77| Hybrid | Split workloads | Both |7879## Key Crates8081| Purpose | Crate |82|---------|-------|83| MQTT (std) | rumqttc, paho-mqtt |84| Embedded | embedded-hal, embassy |85| Async (std) | tokio |86| Async (no_std) | embassy |87| Logging (no_std) | defmt |88| Logging (std) | tracing |8990## Design Patterns9192| Pattern | Purpose | Implementation |93|---------|---------|----------------|94| Pub/Sub | Device comms | MQTT topics |95| Edge compute | Local processing | Filter before upload |96| OTA updates | Firmware upgrade | Signed + rollback |97| Power mgmt | Battery life | Sleep + wake events |98| Store & forward | Network reliability | Local queue |99100## Code Pattern: MQTT Client101102```rust103use rumqttc::{AsyncClient, MqttOptions, QoS};104105async fn run_mqtt() -> anyhow::Result<()> {106 let mut options = MqttOptions::new("device-1", "broker.example.com", 1883);107 options.set_keep_alive(Duration::from_secs(30));108109 let (client, mut eventloop) = AsyncClient::new(options, 10);110111 // Subscribe to commands112 client.subscribe("devices/device-1/commands", QoS::AtLeastOnce).await?;113114 // Publish telemetry115 tokio::spawn(async move {116 loop {117 let data = read_sensor().await;118 client.publish("devices/device-1/telemetry", QoS::AtLeastOnce, false, data).await.ok();119 tokio::time::sleep(Duration::from_secs(60)).await;120 }121 });122123 // Process events124 loop {125 match eventloop.poll().await {126 Ok(event) => handle_event(event).await,127 Err(e) => {128 tracing::error!("MQTT error: {}", e);129 tokio::time::sleep(Duration::from_secs(5)).await;130 }131 }132 }133}134```135136---137138## Common Mistakes139140| Mistake | Domain Violation | Fix |141|---------|-----------------|-----|142| No retry logic | Lost data | Exponential backoff |143| Always-on radio | Battery drain | Sleep between sends |144| Unencrypted MQTT | Security risk | TLS |145| No local buffer | Network outage = data loss | Persist locally |146147---148149## Trace to Layer 1150151| Constraint | Layer 2 Pattern | Layer 1 Implementation |152|------------|-----------------|------------------------|153| Offline-first | Store & forward | Local queue + flush |154| Power efficiency | Sleep patterns | Timer-based wake |155| Network reliability | Retry | tokio-retry, backoff |156| Security | TLS | rustls, native-tls |157158---159160## Related Skills161162| When | See |163|------|-----|164| Embedded patterns | domain-embedded |165| Async patterns | m07-concurrency |166| Error recovery | m13-domain-error |167| Performance | m10-performance |
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