---
phase: 03-container-actions
plan: 04
subsystem: api
tags: [docker-api, container-update, telegram, n8n, image-pull, container-recreation]

# Dependency graph
requires:
  - phase: 03-01-basic-actions
    provides: Container lifecycle API patterns, fuzzy matching, action routing structure
provides:
  - Container update command (pull new image + recreate)
  - Image digest comparison for change detection
  - Silent no-update behavior
  - Container config preservation during recreation
affects: [04-logs, 05-polish]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Image pull via POST /images/create?fromImage=X"
    - "Image digest comparison for update detection"
    - "Container config extraction from inspect endpoint"
    - "NetworkingConfig preservation from NetworkSettings"

key-files:
  created: []
  modified:
    - n8n-workflow.json

key-decisions:
  - "Silent when no update available - only notify on actual image change"
  - "Single container match only for update - no batch updates"
  - "Version detection from OCI labels with ID fallback"
  - "Preserve Hostname/Domainname removal during container recreation"

patterns-established:
  - "Multi-step container operations: inspect -> modify -> recreate"
  - "Image version extraction from org.opencontainers.image.version or version labels"
  - "Sequential container lifecycle: stop -> remove -> create -> start"

# Metrics
duration: 8min
completed: 2026-01-30
---

# Phase 03 Plan 04: Container Update Action Summary

**Container update workflow with image pull, digest comparison, and config-preserving recreation with version change reporting**

## Performance

- **Duration:** 8 min
- **Started:** 2026-01-30T18:24:33Z
- **Completed:** 2026-01-30T18:33:00Z
- **Tasks:** 3
- **Files modified:** 1

## Accomplishments
- Update command routing with single-match-only requirement
- Image pull and digest comparison for detecting actual updates
- Container recreation preserving all configuration (Config, HostConfig, Networks)
- Version change display from image labels or ID substring
- Silent behavior when image already up-to-date

## Task Commits

All three tasks were implemented together (continuation of interrupted session):

1. **Tasks 1-3: Complete update workflow** - `04321c1` (feat)
   - Update command routing and container matching
   - Image pull and change detection
   - Container recreation workflow

## Files Created/Modified
- `n8n-workflow.json` - Extended with 29 new nodes for update flow:
  - Parse Update Command, Docker List for Update, Match Update Container
  - Check Update Match Count, Handle Update Multiple, Send Update Error/No Match/Multiple
  - Build Inspect Command, Inspect Container, Parse Container Config
  - Build Pull Command, Pull Image, Build Image Inspect, Inspect New Image
  - Compare Digests, Check If Update Needed
  - Build Stop Command, Stop Container, Verify Stop Build Remove
  - Remove Container, Build Create Body, Build Create Command
  - Create Container, Parse Create Response
  - Build Start Command, Start New Container
  - Format Update Result, Send Update Result

## Decisions Made
- **Silent on no-update:** When image digest hasn't changed, send no message (per CONTEXT.md)
- **Single match only:** Update command requires exact container name; multiple matches show disambiguation message
- **Version detection hierarchy:** Check org.opencontainers.image.version label, then version label, then use image ID substring
- **NetworkingConfig preservation:** Extract from NetworkSettings.Networks with IPAMConfig, Links, and Aliases

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
- Session was interrupted during initial execution (rate limit)
- Nodes were created but connections were missing
- Connections were added to complete the workflow wiring
- All work committed as single comprehensive commit

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- All container actions complete (start, stop, restart, update)
- Phase 03 fully complete
- Ready for Phase 04: Logs & Intelligence

---
*Phase: 03-container-actions*
*Completed: 2026-01-30*