---
id: T02
parent: S03
milestone: M001
provides: []
requires: []
affects: []
key_files: ["docker/Dockerfile.engine", "engine/api/routes.py", ".dockerignore"]
key_decisions: ["Multi-stage build separates build deps (build-essential, potrace-dev, agg-dev) from runtime (libpotrace0, libagg2, curl)", "Health endpoint at /engine/health for namespace consistency with other /engine/* routes", "Engine image contains only engine source (api, pipeline, output, presets, main.py) — no App dependencies"]
patterns_established: []
drill_down_paths: []
observability_surfaces: []
duration: ""
verification_result: "Built image successfully (exit 0), ran container on port 8100, confirmed /engine/health returns {"status":"ok"}, Docker health status shows "healthy" with 0 failing streak, presets endpoint works from container, no App files in image, full test suite passes (196/196), preset tests pass (28/28)."
completed_at: 2026-03-26T04:49:33.510Z
blocker_discovered: false
---

# T02: Created multi-stage Dockerfile.engine with healthcheck endpoint; container builds, starts, and responds healthy on /engine/health

> Created multi-stage Dockerfile.engine with healthcheck endpoint; container builds, starts, and responds healthy on /engine/health

## What Happened
---
id: T02
parent: S03
milestone: M001
key_files:
  - docker/Dockerfile.engine
  - engine/api/routes.py
  - .dockerignore
key_decisions:
  - Multi-stage build separates build deps (build-essential, potrace-dev, agg-dev) from runtime (libpotrace0, libagg2, curl)
  - Health endpoint at /engine/health for namespace consistency with other /engine/* routes
  - Engine image contains only engine source (api, pipeline, output, presets, main.py) — no App dependencies
duration: ""
verification_result: passed
completed_at: 2026-03-26T04:49:33.527Z
blocker_discovered: false
---

# T02: Created multi-stage Dockerfile.engine with healthcheck endpoint; container builds, starts, and responds healthy on /engine/health

**Created multi-stage Dockerfile.engine with healthcheck endpoint; container builds, starts, and responds healthy on /engine/health**

## What Happened

Created docker/Dockerfile.engine as a two-stage build: builder stage installs build-essential, libagg-dev, and libpotrace-dev to compile pypotrace, then installs all Python deps into /opt/venv. Runtime stage uses python:3.11-slim with only runtime libs (libpotrace0, libagg2, curl), copies the venv, and copies only engine source code. Added GET /engine/health endpoint returning {"status": "ok"} to engine/api/routes.py. Configured Docker HEALTHCHECK instruction (15s interval, 5s timeout, 10s start-period, 3 retries). Added .dockerignore for clean builds. Verified container builds, starts, responds healthy, and contains no App/frontend code.

## Verification

Built image successfully (exit 0), ran container on port 8100, confirmed /engine/health returns {"status":"ok"}, Docker health status shows "healthy" with 0 failing streak, presets endpoint works from container, no App files in image, full test suite passes (196/196), preset tests pass (28/28).

## Verification Evidence

| # | Command | Exit Code | Verdict | Duration |
|---|---------|-----------|---------|----------|
| 1 | `docker build -f docker/Dockerfile.engine -t kerf-engine:dev .` | 0 | ✅ pass | 78700ms |
| 2 | `curl -sf http://localhost:8100/engine/health` | 0 | ✅ pass | 5100ms |
| 3 | `docker inspect kerf-engine-test --format='{{json .State.Health.Status}}'` | 0 | ✅ pass | 200ms |
| 4 | `cd engine && .venv/bin/python -m pytest tests/ -v -k preset` | 0 | ✅ pass | 600ms |
| 5 | `cd engine && .venv/bin/python -m pytest tests/ -v` | 0 | ✅ pass | 940ms |


## Deviations

Added /engine/health on the router for namespace consistency (root /health already existed in main.py). Both endpoints now coexist.

## Known Issues

None.

## Files Created/Modified

- `docker/Dockerfile.engine`
- `engine/api/routes.py`
- `.dockerignore`


## Deviations
Added /engine/health on the router for namespace consistency (root /health already existed in main.py). Both endpoints now coexist.

## Known Issues
None.
