starting work on a docker build

dockerfile

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+# ---------------------------
+# Builder stage
+# ---------------------------
+FROM python:3.11-alpine AS builder
+
+WORKDIR /build
+
+# Build dependencies
+RUN apk add --no-cache \
+    build-base \
+    linux-headers \
+    python3-dev
+
+COPY pyproject.toml .
+COPY repeater ./repeater
+
+# Build wheels (including spidev)
+RUN pip wheel --no-cache-dir --wheel-dir /wheels .
+
+# ---------------------------
+# Runtime stage
+# ---------------------------
+FROM python:3.11-alpine
+
+ENV PYTHONUNBUFFERED=1 \
+    CONFIG_PATH=/etc/pymc_repeater/config.yaml
+
+ARG UID=10001
+ARG GID=10001
+
+# Create non-root user
+RUN addgroup -g ${GID} repeater && \
+    adduser -D -u ${UID} -G repeater repeater
+
+WORKDIR /opt/pymc_repeater
+
+# Copy wheels from builder
+COPY --from=builder /wheels /wheels
+
+# Install from wheels only
+RUN pip install --no-cache-dir /wheels/* && \
+    rm -rf /wheels
+
+# Config directory
+RUN mkdir -p /etc/pymc_repeater && \
+    chown -R ${UID}:${GID} /etc/pymc_repeater
+
+USER ${UID}:${GID}
+
+EXPOSE 8000
+
+ENTRYPOINT ["/bin/sh", "-c", "test -f ${CONFIG_PATH} || (echo 'Missing config.yaml' && exit 1); exec python3 -m repeater --config ${CONFIG_PATH}"]