docker: switch back to debian base image

Alpine builds are taking a very long time, possibly due to python dependencies
lacking pre-built musl wheels [1]. Moreover resulting image sizes are
comparable so benefit of alpine here is ambiguous at best.

[1] https://megamorf.gitlab.io/2020/05/06/why-it-s-better-not-to-use-alpine-linux-for-python-projects/

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3-alpine
+FROM python:3.10.5-bullseye
 
 RUN mkdir /app
 WORKDIR /app
@@ -9,44 +9,49 @@ ENV SHELL=/bin/sh \
    KEGBOT_IN_DOCKER=True \
    KEGBOT_ENV=debug
 
-RUN apk update && \
-    apk add --no-cache \
-      bash \
+# Install toolchains. Mostly, image libraries that Python PIL/Pillow will require.
+RUN apt-get -qq update \
+   && DEBIAN_FRONTEND=noninteractive apt-get -y install \
       curl \
-      libjpeg \
-      libjpeg-turbo \
-      openjpeg \
-      mariadb-connector-c-dev \
-      libpq && \
-   apk add --no-cache --virtual _build-deps \
-     build-base \
-     mariadb-dev \
-     postgresql-dev \
-     libjpeg-turbo-dev \
-     zlib-dev \
-     py-gevent \
-     libffi-dev \
-     musl-dev \
-     python3-dev \
-     openssl-dev \
-     cargo
-
-RUN pip install poetry
-
+      libffi-dev \
+      libfreetype6-dev \
+      libfribidi-dev \
+      libharfbuzz-dev \
+      libjpeg-turbo-progs \
+      libjpeg62-turbo-dev \
+      liblcms2-dev \
+      libopenjp2-7-dev \
+      libtiff5-dev \
+      libwebp-dev \
+      libssl-dev \
+      zlib1g-dev \
+  && rm -rf /var/lib/apt/lists/* \
+  && python -m pip install -U pip \
+  # The cryptography build requires rust, which adds >1GB to the image. \
+  # Install it only to install cryptography, then remove it. \
+  && curl https://sh.rustup.rs -sSf | sh -s -- -y \
+  && pip install cryptography \
+  && rm -rf /root/.rustup /root/.cargo \
+  && pip install poetry \
+  && rm -rf /root/.cache
+
+# Install python dependencies.
 COPY pyproject.toml poetry.lock ./
 ADD pykeg/__init__.py ./pykeg/
 RUN poetry config virtualenvs.create false && poetry install -n
 
+# Install the app itself.
 ADD bin ./bin
 ADD pykeg ./pykeg
 RUN poetry run python bin/kegbot collectstatic --noinput -v 0
 
+# Tag the build with build information.
 ARG GIT_SHORT_SHA="unknown"
 ARG VERSION="unknown"
 ARG BUILD_DATE="unknown"
-RUN echo "GIT_SHORT_SHA=${GIT_SHORT_SHA}" > /etc/kegbot-version
-RUN echo "VERSION=${VERSION}" >> /etc/kegbot-version
-RUN echo "BUILD_DATE=${BUILD_DATE}" >> /etc/kegbot-version
+RUN echo "GIT_SHORT_SHA=${GIT_SHORT_SHA}" \
+   && echo "VERSION=${VERSION}" \
+   && echo "BUILD_DATE=${BUILD_DATE}" /etc/kegbot-version
 
 VOLUME  ["/kegbot-data"]