Create a more compact docker image (remove dev packages from image)

Dockerfile

@@ -2,20 +2,38 @@ FROM alpine:latest
 
 LABEL maintainer="[email protected]"
 
+ARG UID=1337
+ARG GID=1337
 ENV RESTORE false
 ENV ARCHIVE_FILE ""
 
-RUN echo "@edge http://dl-cdn.alpinelinux.org/alpine/edge/community" >> /etc/apk/repositories \
-    && apk --no-cache add python3-dev libffi-dev gcc libc-dev py3-pip py3-cffi py3-cryptography ca-certificates bash
+ENV DEV_PACKAGES="\
+    gcc \
+    libc-dev \
+    libffi-dev \
+    py3-pip \
+    python3-dev \
+"
 
+ENV PACKAGES="\
+    bash \
+    ca-certificates \
+    py3-cffi \
+    py3-cryptography \
+    py3-six \
+"
 WORKDIR /opt/grafana-backup-tool
 ADD . /opt/grafana-backup-tool
 
 RUN chmod -R a+r /opt/grafana-backup-tool \
  && find /opt/grafana-backup-tool -type d -print0 | xargs -0 chmod a+rx
 
-RUN pip3 --no-cache-dir install .
+RUN echo "@edge http://dl-cdn.alpinelinux.org/alpine/edge/community" >> /etc/apk/repositories \
+    && apk add --no-cache --virtual build-deps ${DEV_PACKAGES} \
+    && apk add --no-cache ${PACKAGES} \
+    && pip3 --no-cache-dir install . \
+    && chown -R ${UID}:${GID} /opt/grafana-backup-tool \
+    && apk del build-deps
 
-RUN chown -R 1337:1337 /opt/grafana-backup-tool
-USER 1337
+USER ${UID}
 CMD sh -c 'if [ "$RESTORE" = true ]; then if [ ! -z "$AWS_S3_BUCKET_NAME" ] || [ ! -z "$AZURE_STORAGE_CONTAINER_NAME" ]; then grafana-backup restore $ARCHIVE_FILE; else grafana-backup restore _OUTPUT_/$ARCHIVE_FILE; fi else grafana-backup save; fi'