Simpler Dockerfile

Inspired by #1087

Dockerfile

@@ -1,27 +1,7 @@
-FROM alpine:latest
+FROM python:3-alpine
 
 # Version of Radicale (e.g. 3.0.x)
 ARG VERSION=master
-
-# Install dependencies
-RUN apk add --no-cache \
-      python3 \
-      py3-pip \
-      python3-dev \
-      build-base \
-      libffi-dev \
-      ca-certificates \
-      openssl
-# Install Radicale
-RUN wget --quiet https://github.com/Kozea/Radicale/archive/${VERSION}.tar.gz --output-document=radicale.tar.gz && \
-    tar xzf radicale.tar.gz && \
-    pip3 install ./Radicale-${VERSION}[bcrypt] && \
-    rm -r radicale.tar.gz Radicale-${VERSION}
-# Remove build dependencies
-RUN apk del \
-      python3-dev \
-      build-base \
-      libffi-dev
 # Persistent storage for data (Mount it somewhere on the host!)
 VOLUME /var/lib/radicale
 # Configuration data (Put the "config" file here!)
@@ -30,3 +10,10 @@ VOLUME /etc/radicale
 EXPOSE 5232
 # Run Radicale (Configure it here or provide a "config" file!)
 CMD ["radicale", "--hosts", "0.0.0.0:5232"]
+
+# Install dependencies
+RUN apk add --no-cache gcc musl-dev libffi-dev ca-certificates openssl
+# Install Radicale
+RUN pip install --no-cache-dir "Radicale[bcrypt] @ https://github.com/Kozea/Radicale/archive/${VERSION}.tar.gz"
+# Remove build dependencies
+RUN apk del gcc musl-dev libffi-dev