Docker: Support for setting cron schedule, PUID, GUID and time zone via env vars.

docker/Dockerfile

@@ -2,30 +2,27 @@ FROM alpine:latest
 
 ENV TZ="UTC"
 ENV SCHEDULE="* * * * *"
+ENV PUID=1000
+ENV PGID=1000
 
 ## Configure runtime variables for nsupdate
 ENV NSUPDATE_CONFD_DIR="/config"
 ENV NSUPDATE_LOG_DIR="/log"
 
 ## Install requirements
-RUN apk update
 RUN apk add --no-cache git curl libxml2-utils tzdata jq
 
-# Read timezone from server, so in docker-compose you can change TZ
-RUN ln -sf "/usr/share/zoneinfo/${TZ}" /etc/localtime && \
-    echo "${TZ}" > /etc/timezone && date
-
 # Cache Bust upon new commits
 ADD https://api.github.com/repos/chrisb86/nsupdate/git/refs/heads/main /.git-hashref
 
-COPY nsupdate.sh /usr/local/bin/nsupdate.sh
-RUN chmod +x /usr/local/bin/nsupdate.sh
+COPY --chmod=755 nsupdate.sh /usr/local/bin/nsupdate.sh
+COPY --chmod=755 docker/entrypoint.sh /usr/local/bin/entrypoint.sh
 
-## Setup cron job
-RUN echo "${SCHEDULE} sh /usr/local/bin/nsupdate.sh" >> /etc/crontabs/root
+# Create volume directories (ownership will be set at runtime)
+RUN mkdir -p /config /log
 
 ## Start crond
-CMD [ "crond", "-l", "2", "-f" ]
+ENTRYPOINT [ "/usr/local/bin/entrypoint.sh" ]
 
 VOLUME /config
-VOLUME /log
+VOLUME /log