Publish OTA Progress and Status to MQTT

[rodneyosodo]

Overview

Implement OTA status topic publishing to report download progress, verification status, and update state over MQTT.

Description

Aeolus publishes OTA progress to the ota/status topic so administrators can monitor update progress in real-time. The current Linux OTA implementation exists but doesn't publish status to MQTT.

Requirements

1. Status Topic

   • Publish to m/{domain}/c/{ctrl_channel}/ota/status
   • Update on state transitions
   • Update on download progress (every 5%)
   • Use SenML format

2. Status Fields

   • state - Current state (idle, downloading, verifying, ready, restarting, aborted)
   • bytes - Bytes downloaded so far
   • total - Total bytes expected
   • progress - Percentage complete (0-100)
   • error - Error message (if any)

3. State Publishing

   • Publish on each state transition
   • Publish periodically during download
   • Publish final status on completion/abort
   • Retain last status message

4. OTA Config Topic

   • Subscribe to m/{domain}/c/{ctrl_channel}/ota/cfg
   • Parse update trigger
   • Support URL, hash, and size fields

5. OTA Data Topic

   • Subscribe to m/{domain}/c/{ctrl_channel}/ota
   • Receive firmware binary via MQTT streaming
   • Alternative to HTTP download

Status Format

[
  {
    "n": "state",
    "vs": "downloading"
  },
  {
    "n": "bytes",
    "v": 65536,
    "u": "By"
  },
  {
    "n": "total",
    "v": 1324740,
    "u": "By"
  }
]

Reference

See Aeolus implementation:

• src/management/ota.c
• docs/ota.md
• Current OTA implementation in pkg/ota/ota.go

Acceptance Criteria

• OTA status topic publishes state changes
• Download progress publishes every 5%
• Status includes bytes downloaded and total
• Final status published on completion
• Error status published on failure
• OTA can be triggered via MQTT config topic
• MQTT streaming download works
• HTTP download still works
• ProgressFn callback integrated with MQTT publisher
• Integration tests for status publishing

Priority

High