switch to a manual build of pip deps

Dockerfile

@@ -1,11 +1,47 @@
+FROM alpine:latest as builder
+
+COPY cioban/requirements.txt /work/cioban/requirements.txt
+
+ENV CRYPTOGRAPHY_DONT_BUILD_RUST="1"
+
+RUN set -xeu; \
+    mkdir -p /work/wheels; \
+    apk add \
+      python3-dev \
+      openssl-dev \
+      gcc \
+      musl-dev \
+      libffi-dev \
+      make \
+      openssl-dev \
+      cargo \
+    ; \
+    python3 -m ensurepip; \
+    pip3 install -U \
+      wheel \
+      pip
+
+RUN pip3 wheel --prefer-binary -r /work/cioban/requirements.txt -w /work/wheels
+
 FROM alpine:latest
+
 LABEL maintainer="[email protected]" \
       ai.ix.repository="ix.ai/cioban"
 
-COPY cioban/requirements.txt /cioban/requirements.txt
+COPY --from=builder /work /
 
-RUN apk add --no-cache python3 py3-cryptography py3-pip && \
-    pip3 install --no-cache-dir -r /cioban/requirements.txt
+RUN set -xeu; \
+    ls -lashi /wheels; \
+    apk add --no-cache python3; \
+    python3 -m ensurepip; \
+    pip3 install --no-cache-dir -U pip;\
+    pip3 install \
+      --no-index \
+      --no-cache-dir \
+      --find-links /wheels \
+      --requirement /cioban/requirements.txt \
+    ; \
+    rm -rf /wheels
 
 COPY cioban/ /cioban
 COPY cioban.sh /usr/local/bin/cioban.sh