# Update Manager

**Task**: AZ-185_update_manager
**Name**: Update Manager
**Description**: Implement the loader's background update loop that checks for new versions and applies AI model and Docker image updates
**Complexity**: 5 points
**Dependencies**: AZ-183, AZ-184
**Component**: Loader
**Tracker**: AZ-185
**Epic**: AZ-181

## Problem

Jetsons need to automatically discover and install new AI models and Docker images without manual intervention. The update loop must handle version detection, server communication, and applying different update types.

## Outcome

- Loader automatically checks for updates every 5 minutes
- New AI models downloaded, decrypted, and placed in model directory
- New Docker images loaded and services restarted with minimal downtime
- Loader can update itself (self-update, applied last)

## Scope

### Included
- Version collector: scan model directory for .trt files (extract date from filename), query docker images for azaion/* tags, cache results
- Background loop (configurable interval, default 5 min): collect versions, call POST /get-update, trigger downloads
- Apply AI model: move decrypted .trt to model directory (detection API scans and picks newest)
- Apply Docker image: docker load -i, docker compose up -d {service}
- Self-update: loader updates itself last via docker compose up -d loader
- Integration with AZ-184 Resumable Download Manager for all downloads

### Excluded
- Server-side /get-update endpoint (AZ-183)
- Download mechanics (AZ-184)
- CI/CD publish pipeline (AZ-186)
- Device provisioning (AZ-187)

## Acceptance Criteria

**AC-1: Version collector reads local state**
Given AI model azaion-2026-03-10.trt in model directory and Docker image azaion/annotations:arm64_2026-03-01 loaded
When version collector runs
Then it reports [{resource_name: "detection_model", version: "2026-03-10"}, {resource_name: "annotations", version: "arm64_2026-03-01"}]

**AC-2: Background loop polls on schedule**
Given the loader is running with update interval set to 5 minutes
When 5 minutes elapse
Then POST /get-update is called with current versions

**AC-3: AI model update applied**
Given /get-update returns a new detection_model version
When download and decryption complete
Then new .trt file is in the model directory

**AC-4: Docker image update applied**
Given /get-update returns a new annotations version
When download and decryption complete
Then docker load succeeds and docker compose up -d annotations restarts the service

**AC-5: Self-update applied last**
Given /get-update returns updates for both annotations and loader
When applying updates
Then annotations is updated first, loader is updated last

**AC-6: Cached versions refresh after changes**
Given version collector cached its results
When a new model file appears in the directory or docker load completes
Then cache is invalidated and next collection reflects new state

## Constraints

- Docker socket must be mounted in the loader container (already the case)
- docker compose file path must be configurable (env var)
- Model directory path must be configurable (env var)
- Self-update must be robust: state file on disk ensures in-progress updates survive container restart