Changed heartbeat database update from synchronous to async using Task.start.
This reduces response time from ~20ms to <1ms by not waiting for the
database write to complete before sending the response.
The heartbeat is a fire-and-forget operation where the agent doesn't
need confirmation that the update succeeded.
In test environment, it remains synchronous to avoid DB ownership issues.
Fixed two critical issues preventing agent communication:
1. Fix Mix.env() runtime error in production
- Replace Mix.env() with Application.get_env(:towerops, :env)
- Add :env config to test.exs
- Mix module not available in production releases
2. Add Protocol Buffers support to agent API endpoints
- GET /api/v1/agent/config now accepts application/x-protobuf
- POST /api/v1/agent/heartbeat now accepts application/x-protobuf
- Added conversion functions for config/equipment/sensors/interfaces
- Maintains JSON backward compatibility as fallback
All agent controller tests passing (14 tests, 0 failures)
Add three-level agent assignment hierarchy (Equipment > Site > Organization)
allowing flexible agent deployment strategies. Agents now receive only equipment
assigned to them through direct assignment or inheritance from site/organization
defaults.
Key changes:
- Add agent_token_id to Sites table with migration
- Implement get_effective_agent_token/1 for hierarchical resolution
- Add list_agent_polling_targets/1 to return polling targets per agent
- Update API config endpoint to use hierarchical polling targets
- Add agent assignment UI to equipment, site, and organization forms
- Show agent source (direct/site/org/none) in equipment form
- Add equipment count column to agent list
- Update terminology from "poll from server" to "cloud polling"
Tests:
- Add 8 comprehensive tests for list_agent_polling_targets/1
- Add end-to-end test for hierarchical config endpoint
- All 775 tests passing
