Architecture 11 Risks And Technical Debt

11. Risks and technical debt

Risk	Mitigation
Unofficial protocol: a Mammotion firmware update can break features	Pin the PyMammotion version; apply mower firmware updates only after community feedback
Double access while the existing Mammotion integration in Home Assistant runs	In the spike use a second shared Mammotion account; remove the old integration after the MVP
Safety when driving or spot mowing	Dead-man switch, blade off in transfer, visible emergency stop, never bypass sensor stops
Login and access	Pluggable login, Argon2id, API tokens per client, login rate limit, short sessions, access from outside only via Tailscale or HTTPS proxy
Maintenance effort of many small programs	Monorepo, shared contracts, one CI, versioned public API early
Terms of use	Uncritical for personal use; review before redistribution
WLAN control not yet available	Bluetooth is default; WLAN is a second adapter behind the same interface
Microservice complexity for one household	Same pattern for every service, one Compose file, interfaces that would allow several services in one process
Data leaks between accounts	Account ID only from token, filter in each query, per-service tests with foreign data
Distributed failures	Command IDs, expiry, emergency stop priority, traces across services
Payment and legal duties once others pay	Only in Phase 4; choose a provider that handles taxes

Open questions for the spike

• Does PyMammotion deliver map geometry (zones, paths, dock) in a usable form?
• Does it support manual driving and mowing jobs with own limits?
• How does the camera stream leave the mower and can it be tapped locally?
• What is the command latency over the Bluetooth bridge, and is it enough for the joystick?
• Which entities and services should the HACS integration offer?
• Does it fully support 4G mowers and network RTK, including fix status and cellular connection?
• Does the mower report the correction source (station or network RTK)?
• Which bridge firmware: ESPHome Bluetooth proxy or a lean custom ESP32 firmware?
• Payment provider for EU customers: Stripe with tax module or a merchant of record such as Paddle?
• How many mower connections can one Device-Gateway instance hold (sharding size)?
• Can the LUBA drive arbitrary paths or only zones with its own patterns (own route versus native job)?

Technical debt

None recorded yet. Known deliberate shortcuts: the Compose stack uses one shared password for all service database roles and mounts the Docker socket read-only into Traefik; both are acceptable for the development defaults and must be revisited before cloud operation.

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