infoscreen/implementation-plans/server-team-actions.md

Server Team Action Items — Infoscreen Client

This document lists everything the server/infrastructure/frontend team must implement to complete the client integration. The client-side code is production-ready for all items listed here.

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1. MQTT Broker Hardening (prerequisite for everything else)

• Disable anonymous access on the broker.
• Create one broker account per client device:
  • Username convention: infoscreen-client-<uuid-prefix> (e.g. infoscreen-client-9b8d1856)
  • Provision the password to the device .env as MQTT_PASSWORD_BROKER=
• Create a server/publisher account (e.g. infoscreen-server) for all server-side publishes.
• Enforce ACLs:

Topic	Publisher
infoscreen/{uuid}/commands	server only
infoscreen/{uuid}/command (alias)	server only
infoscreen/{uuid}/group_id	server only
infoscreen/events/{group_id}	server only
infoscreen/groups/+/power/intent	server only
infoscreen/{uuid}/commands/ack	client only
infoscreen/{uuid}/command/ack	client only
infoscreen/{uuid}/heartbeat	client only
infoscreen/{uuid}/health	client only
infoscreen/{uuid}/logs/#	client only
infoscreen/{uuid}/service_failed	client only

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2. Reboot / Shutdown Command — Ack Lifecycle

Client publishes ack status updates to two topics per command (canonical + transitional alias):

• infoscreen/{uuid}/commands/ack
• infoscreen/{uuid}/command/ack

Ack payload schema (v1, frozen):

{
  "command_id": "07aab032-53c2-45ef-a5a3-6aa58e9d9fae",
  "status": "accepted | execution_started | completed | failed",
  "error_code": null,
  "error_message": null
}

Status lifecycle:

Status	When	Notes
accepted	Command received and validated	Immediate
execution_started	Helper invoked	Immediate after accepted
completed	Execution confirmed	For reboot_host: arrives after reconnect (10–90 s after execution_started)
failed	Helper returned error	error_code and error_message will be set

Server must:

• Track command_id through the full lifecycle and update status in DB/UI.
• Surface failed + error_code to the operator UI.
• Expect reboot_host completed to arrive after a reconnect delay — do not treat the gap as a timeout.
• Use expires_at from the original command to determine when to abandon waiting.

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3. Health Dashboard — Broker Connection Fields (Gap 2)

Every infoscreen/{uuid}/health payload now includes a broker_connection block:

{
  "timestamp": "2026-04-05T08:00:00.000000+00:00",
  "expected_state": { "event_id": 42 },
  "actual_state": {
    "process": "display_manager",
    "pid": 1234,
    "status": "running"
  },
  "broker_connection": {
    "broker_reachable": true,
    "reconnect_count": 2,
    "last_disconnect_at": "2026-04-04T10:30:00Z"
  }
}

Server must:

• Display reconnect_count and last_disconnect_at per device in the health dashboard.
• Implement alerting heuristic:
  • All clients go silent simultaneously → likely broker outage, not device crash.
  • Single client goes silent → device crash, network failure, or process hang.

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4. Service-Failed MQTT Notification (Gap 3)

When systemd gives up restarting a service after repeated crashes (StartLimitBurst exceeded), the client automatically publishes a retained message:

Topic: infoscreen/{uuid}/service_failed

Payload:

{
  "event": "service_failed",
  "unit": "infoscreen-simclient.service",
  "client_uuid": "9b8d1856-ff34-4864-a726-12de072d0f77",
  "failed_at": "2026-04-05T08:00:00Z"
}

Server must:

• Subscribe to infoscreen/+/service_failed on startup (retained — message survives broker restart).
• Alert the operator immediately when this topic receives a payload.
• Clear the retained message once the device is acknowledged or recovered:

  mosquitto_pub -t "infoscreen/{uuid}/service_failed" -n --retain
  

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5. No Server Action Required

These items are fully implemented client-side and require no server changes:

• systemd watchdog (WatchdogSec=60) — hangs detected and process restarted automatically.
• Command deduplication — command_id deduplicated with 24-hour TTL.
• Ack retry backoff — client retries ack publish on broker disconnect until expires_at.
• Mock helper / test mode (COMMAND_MOCK_REBOOT_IMMEDIATE_COMPLETE) — development only.