Merge pull request #2035 from casperklein/crond

Make crond and cron job output visible in "docker log"

Author: PromoFaux

src/Dockerfile

@@ -98,6 +98,7 @@ RUN cd /etc/.pihole && \
     echo "${PIHOLE_DOCKER_TAG}" > /pihole.docker.tag
 
 COPY --chmod=0755 bash_functions.sh /usr/bin/bash_functions.sh
+COPY --chmod=0755 prefix-time.sh /usr/bin/prefix-time.sh
 COPY --chmod=0755 start.sh /usr/bin/start.sh
 
 EXPOSE 53 53/udp

src/bash_functions.sh

@@ -89,7 +89,9 @@ start_cron() {
         echo "  [!] Failed to install crontab - scheduled tasks (gravity, update checker) will not run"
     fi
 
-    /usr/sbin/crond
+    # Run crond in foreground, prefix each line from STDIN/STDOUT with the current date/time/timezone and
+    # write to PID 1 STDOUT (docker log)
+    { /usr/sbin/crond -f -d 6 |& prefix-time.sh; } &
     echo ""
 }
 

src/prefix-time.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+# Prefix each line from STDIN with the current date/time/timezone and write to PID 1 STDOUT (docker log)
+while IFS= read -r line; do
+    printf '%s %s\n' "$(date '+%F %T.%3N %Z')" "$line" >>/proc/1/fd/1
+done