feat: Created multi-stage Dockerfile.engine with healthcheck endpoint;…

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

GSD-Task: S03/T02

.dockerignore

@@ -0,0 +1,22 @@
+# Kerf Engine — Docker build context exclusions
+.git
+.gsd
+.venv
+venv
+__pycache__
+*.pyc
+*.pyo
+.pytest_cache
+*.egg-info
+.env
+.env.*
+node_modules
+.next
+dist
+build
+coverage
+.cache
+tmp
+*.log
+.DS_Store
+Thumbs.db

docker/Dockerfile.engine

@@ -0,0 +1,61 @@
+# ── Kerf Engine — multi-stage Docker build ──
+# Standalone raster-to-vector conversion API (no App dependencies)
+
+# ── Stage 1: Build dependencies ──
+FROM python:3.11-slim AS builder
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        build-essential \
+        pkg-config \
+        libagg-dev \
+        libpotrace-dev \
+        libpotrace0 \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /build
+
+# Install Python deps into a virtual-env we can copy later
+RUN python -m venv /opt/venv
+ENV PATH="/opt/venv/bin:$PATH"
+
+COPY engine/pyproject.toml .
+RUN pip install --no-cache-dir . 2>/dev/null || true
+# The above may fail because package source isn't present yet — install deps directly
+RUN pip install --no-cache-dir \
+        "fastapi>=0.110" \
+        "uvicorn[standard]>=0.29" \
+        "opencv-python-headless>=4.9" \
+        "pypotrace>=0.3" \
+        "vtracer>=0.6" \
+        "python-multipart>=0.0.9" \
+        "Pillow>=10.2" \
+        "ezdxf>=1.0"
+
+# ── Stage 2: Runtime image ──
+FROM python:3.11-slim AS runtime
+
+# Runtime-only system libs for pypotrace
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        libpotrace0 \
+        libagg2 \
+        curl \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy the virtual-env from the builder
+COPY --from=builder /opt/venv /opt/venv
+ENV PATH="/opt/venv/bin:$PATH"
+
+# Copy engine source only — no App code
+WORKDIR /app
+COPY engine/main.py .
+COPY engine/api/ ./api/
+COPY engine/pipeline/ ./pipeline/
+COPY engine/output/ ./output/
+COPY engine/presets/ ./presets/
+
+EXPOSE 8000
+
+HEALTHCHECK --interval=15s --timeout=5s --start-period=10s --retries=3 \
+    CMD curl -sf http://localhost:8000/engine/health || exit 1
+
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]

engine/api/routes.py

@@ -14,6 +14,13 @@ from presets.loader import all_presets, preset_names, resolve_params
 
 router = APIRouter()
 
+
+@router.get("/engine/health")
+async def health():
+    """Healthcheck endpoint for container orchestration."""
+    return {"status": "ok"}
+
+
 VALID_MODES = {"potrace", "vtracer"}
 VALID_OUTPUT_FORMATS = {"svg", "dxf", "json"}