From 718ddec618c022301675f8d766ec30b2c1d1f3c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rn-Michael=20Miehe?=
 <40151420+ldericher@users.noreply.github.com>
Date: Tue, 1 Mar 2022 17:57:56 +0100
Subject: [PATCH 1/3] modularity

---
 bin/kiwi-cron                         |  8 ++++++--
 libexec/kiwi-cron/create_schedule     | 21 ++++++-------------
 libexec/kiwi-cron/print_cron_schedule | 11 ----------
 libexec/kiwi-cron/print_crontab       | 26 ++++++++++++++++++++++++
 libexec/kiwi-cron/schedule_dirs       | 29 ++-------------------------
 5 files changed, 40 insertions(+), 55 deletions(-)
 delete mode 100755 libexec/kiwi-cron/print_cron_schedule

diff --git a/bin/kiwi-cron b/bin/kiwi-cron
index ce925f9..bbc3af9 100755
--- a/bin/kiwi-cron
+++ b/bin/kiwi-cron
@@ -1,5 +1,9 @@
 #!/bin/sh
 
-# replace crontab, run crond
-/usr/local/libexec/kiwi-cron/schedule_dirs | crontab -
+# replace crontab
+/usr/local/libexec/kiwi-cron/schedule_dirs \
+  | /usr/local/libexec/kiwi-cron/print_crontab \
+  | crontab -
+
+# run crond
 exec crond -fd 8
\ No newline at end of file
diff --git a/libexec/kiwi-cron/create_schedule b/libexec/kiwi-cron/create_schedule
index 792b346..863b5b4 100755
--- a/libexec/kiwi-cron/create_schedule
+++ b/libexec/kiwi-cron/create_schedule
@@ -1,8 +1,5 @@
 #!/bin/sh
 
-this_script="$( readlink -f "${0}" )"
-this_dir="${this_script%/*}"
-
 cs_every="${1:-1}"
 cs_units="${2}"
 cs_command="${3}"
@@ -36,27 +33,21 @@ cs_rand_month=$(( RANDOM % 2 + 1 ))
 
 case "${cs_units}" in
 minute)
-  "${this_dir}/print_cron_schedule" \
-    "*${cs_every}" "*" "*" "*" "*" "${cs_command}" 
+  echo "*${cs_every}" "*" "*" "*" "*" "${cs_command}" 
   ;;
 hour)
-  "${this_dir}/print_cron_schedule" \
-    "${cs_rand_min}" "*${cs_every}" "*" "*" "*" "${cs_command}" 
+  echo "${cs_rand_min}" "*${cs_every}" "*" "*" "*" "${cs_command}" 
   ;;
 day)
-  "${this_dir}/print_cron_schedule" \
-    "${cs_rand_min}" "${cs_rand_hour}" "*${cs_every}" "*" "*" "${cs_command}" 
+  echo "${cs_rand_min}" "${cs_rand_hour}" "*${cs_every}" "*" "*" "${cs_command}" 
   ;;
 week)
-  "${this_dir}/print_cron_schedule" \
-    "${cs_rand_min}" "${cs_rand_hour}" "*" "*" "${cs_rand_weekday}" "${cs_command}" 
+  echo "${cs_rand_min}" "${cs_rand_hour}" "*" "*" "${cs_rand_weekday}" "${cs_command}" 
   ;;
 month)
-  "${this_dir}/print_cron_schedule" \
-    "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "*${cs_every}" "*" "${cs_command}" 
+  echo "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "*${cs_every}" "*" "${cs_command}" 
   ;;
 year)
-  "${this_dir}/print_cron_schedule" \
-    "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "${cs_rand_month}" "*" "${cs_command}" 
+  echo "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "${cs_rand_month}" "*" "${cs_command}" 
   ;;
 esac
diff --git a/libexec/kiwi-cron/print_cron_schedule b/libexec/kiwi-cron/print_cron_schedule
deleted file mode 100755
index 10067c9..0000000
--- a/libexec/kiwi-cron/print_cron_schedule
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/bin/sh
-
-pcs_minute="${1}"
-pcs_hour="${2}"
-pcs_day="${3}"
-pcs_month="${4}"
-pcs_weekday="${5}"
-pcs_command="${6}"
-
-printf '%-8s%-8s%-8s%-8s%-8s%s\n' \
-  "${pcs_minute}" "${pcs_hour}" "${pcs_day}" "${pcs_month}" "${pcs_weekday}" "${pcs_command}"
diff --git a/libexec/kiwi-cron/print_crontab b/libexec/kiwi-cron/print_crontab
index 13f4793..a2c6a29 100755
--- a/libexec/kiwi-cron/print_crontab
+++ b/libexec/kiwi-cron/print_crontab
@@ -1,2 +1,28 @@
 #!/bin/sh
 
+print_cron_schedule () {
+  pcs_minute="${1}"
+  pcs_hour="${2}"
+  pcs_day="${3}"
+  pcs_month="${4}"
+  pcs_weekday="${5}"
+  pcs_command="${6}"
+
+  printf '%-8s%-8s%-8s%-8s%-8s%s\n' \
+    "${pcs_minute}" "${pcs_hour}" "${pcs_day}" "${pcs_month}" "${pcs_weekday}" "${pcs_command}"
+}
+
+# header
+echo '# crontab generated by kiwi-cron'
+echo '# generation time: '"$(date)"
+echo '#'
+
+# short documentation line
+print_cron_schedule \
+  "# min" "hour" "day" "month" "weekday" "command" 
+
+# schedules
+while read -r pc_min pc_hour pc_day pc_month pc_weekday pc_command; do
+  print_cron_schedule \
+    "${pc_min}" "${pc_hour}" "${pc_day}" "${pc_month}" "${pc_weekday}" "${pc_command}" 
+done
diff --git a/libexec/kiwi-cron/schedule_dirs b/libexec/kiwi-cron/schedule_dirs
index 8214536..e9b79aa 100755
--- a/libexec/kiwi-cron/schedule_dirs
+++ b/libexec/kiwi-cron/schedule_dirs
@@ -3,17 +3,6 @@
 this_script="$( readlink -f "${0}" )"
 this_dir="${this_script%/*}"
 
-crontab=''
-crontab_line () {
-  if [ -z "${crontab}" ]; then
-    crontab="${1}"
-  else
-    crontab="$( 
-      printf '%s\n%s' "${crontab}" "${1}"; 
-    )"
-  fi
-}
-
 dir_has_no_files () {
   dhnf_directory="${1}"
 
@@ -47,14 +36,6 @@ dir_to_unit () {
   esac
 }
 
-crontab_line '# crontab generated by kiwi-cron'
-crontab_line '# generation time: '"$(date)"
-crontab_line '#'
-crontab_line "$( 
-  "${this_dir}/print_cron_schedule" \
-    "# min" "hour" "day" "month" "weekday" "command" 
-)"
-
 # check *ly dirs in "/kiwi-cron" directory
 schedule_dirs="$( 
   find "/kiwi-cron" -type d -name "*ly" -mindepth 1 -maxdepth 1
@@ -71,9 +52,7 @@ for schedule_dir in ${schedule_dirs}; do
   units="${dir_name%ly}"
   units="$( dir_to_unit "${units}" )"
 
-  crontab_line "$( 
-    "${this_dir}/create_schedule" "1" "${units}" "run-parts '${schedule_dir}'"
-  )"
+  "${this_dir}/create_schedule" "1" "${units}" "run-parts '${schedule_dir}'"
 done
 
 # check dirs in "/kiwi-cron/every" directory
@@ -93,9 +72,5 @@ for schedule_dir in ${every_schedule_dirs}; do
   units="$( echo "${dir_name}" | awk -F_ '{print $2}' )"
   units="${units%s}"
 
-  crontab_line "$( 
-    "${this_dir}/create_schedule" "${every}" "${units}" "run-parts '${schedule_dir}'"
-  )"
+  "${this_dir}/create_schedule" "${every}" "${units}" "run-parts '${schedule_dir}'"
 done
-
-echo "${crontab}"

From 0cd472a08f556c0783cdb0db124dfe1fbea5cc5d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rn-Michael=20Miehe?=
 <40151420+ldericher@users.noreply.github.com>
Date: Tue, 1 Mar 2022 18:40:05 +0100
Subject: [PATCH 2/3] modularity

---
 bin/kiwi-cron                     | 10 +++-----
 libexec/kiwi-cron/create_schedule | 36 ++++++++++++++--------------
 libexec/kiwi-cron/run_cron        | 40 +++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 25 deletions(-)
 create mode 100644 libexec/kiwi-cron/run_cron

diff --git a/bin/kiwi-cron b/bin/kiwi-cron
index bbc3af9..c1e2707 100755
--- a/bin/kiwi-cron
+++ b/bin/kiwi-cron
@@ -1,9 +1,5 @@
 #!/bin/sh
 
-# replace crontab
-/usr/local/libexec/kiwi-cron/schedule_dirs \
-  | /usr/local/libexec/kiwi-cron/print_crontab \
-  | crontab -
-
-# run crond
-exec crond -fd 8
\ No newline at end of file
+exec /usr/local/libexec/kiwi-cron/run_cron \
+  "${@}" \
+  /usr/local/libexec/kiwi-cron/schedule_dirs
diff --git a/libexec/kiwi-cron/create_schedule b/libexec/kiwi-cron/create_schedule
index 863b5b4..34ed88c 100755
--- a/libexec/kiwi-cron/create_schedule
+++ b/libexec/kiwi-cron/create_schedule
@@ -32,22 +32,22 @@ cs_rand_weekday=$(( (6 + RANDOM % 2) % 7 ))
 cs_rand_month=$(( RANDOM % 2 + 1 ))
 
 case "${cs_units}" in
-minute)
-  echo "*${cs_every}" "*" "*" "*" "*" "${cs_command}" 
-  ;;
-hour)
-  echo "${cs_rand_min}" "*${cs_every}" "*" "*" "*" "${cs_command}" 
-  ;;
-day)
-  echo "${cs_rand_min}" "${cs_rand_hour}" "*${cs_every}" "*" "*" "${cs_command}" 
-  ;;
-week)
-  echo "${cs_rand_min}" "${cs_rand_hour}" "*" "*" "${cs_rand_weekday}" "${cs_command}" 
-  ;;
-month)
-  echo "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "*${cs_every}" "*" "${cs_command}" 
-  ;;
-year)
-  echo "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "${cs_rand_month}" "*" "${cs_command}" 
-  ;;
+  minute)
+    echo "*${cs_every}" "*" "*" "*" "*" "${cs_command}" 
+    ;;
+  hour)
+    echo "${cs_rand_min}" "*${cs_every}" "*" "*" "*" "${cs_command}" 
+    ;;
+  day)
+    echo "${cs_rand_min}" "${cs_rand_hour}" "*${cs_every}" "*" "*" "${cs_command}" 
+    ;;
+  week)
+    echo "${cs_rand_min}" "${cs_rand_hour}" "*" "*" "${cs_rand_weekday}" "${cs_command}" 
+    ;;
+  month)
+    echo "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "*${cs_every}" "*" "${cs_command}" 
+    ;;
+  year)
+    echo "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "${cs_rand_month}" "*" "${cs_command}" 
+    ;;
 esac
diff --git a/libexec/kiwi-cron/run_cron b/libexec/kiwi-cron/run_cron
new file mode 100644
index 0000000..347aabb
--- /dev/null
+++ b/libexec/kiwi-cron/run_cron
@@ -0,0 +1,40 @@
+#!/bin/sh
+
+# check for CLI options
+while getopts ':n' rc_optarg; do
+  case "${rc_optarg}" in
+    n)
+      rc_dry_run="yes"
+      ;;
+
+    *)
+      echo "Invalid option: -${OPTARG}."
+      exit 2
+  esac
+done
+
+shift "$(( OPTIND - 1 ))"
+
+# CLI arguments
+rc_executable="${1}"
+
+
+if [ -n "${rc_dry_run}" ]; then
+  # verbose, dry run
+  set -x
+
+  "${rc_executable}" \
+    | /usr/local/libexec/kiwi-cron/print_crontab
+
+  exit 0
+fi
+
+# replace crontab
+"${rc_executable}" \
+  | /usr/local/libexec/kiwi-cron/print_crontab \
+  | crontab -
+
+# hand over to crond
+exec crond -fd 8
+
+exit 0
\ No newline at end of file

From 1d0ef14827f35915bd1783e027f1644dd77f6122 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rn-Michael=20Miehe?=
 <40151420+ldericher@users.noreply.github.com>
Date: Tue, 1 Mar 2022 18:44:09 +0100
Subject: [PATCH 3/3] Time Zones

---
 Dockerfile                 | 3 +++
 README.md                  | 6 ++++++
 libexec/kiwi-cron/run_cron | 4 ++++
 3 files changed, 13 insertions(+)
 mode change 100644 => 100755 libexec/kiwi-cron/run_cron

diff --git a/Dockerfile b/Dockerfile
index 0b29a95..57569c9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,7 @@
 FROM alpine:latest
 
+ENV TZ=Etc/UTC
+
 RUN set -ex; \
     \
     mkdir -pm 755 /kiwi-cron; \
@@ -16,6 +18,7 @@ RUN set -ex; \
     \
     apk --no-cache add \
         docker-cli \
+        tzdata \
     ;
 
 COPY bin /usr/local/bin/
diff --git a/README.md b/README.md
index 141c7a5..fe0507d 100644
--- a/README.md
+++ b/README.md
@@ -28,6 +28,12 @@ For each subdirectory, a random valid cron schedule is generated, so that:
 
 Cron schedules are regenerated once on each startup, only for directories that have files.
 
+## Time Zones
+
+`kiwi-cron` images include the `tzdata` package and automatically handle `/etc/localtime` on startup. By default, "Etc/UTC" is set as the container time zone.
+
+To use a different time zone, change the container environment variable `TZ` to your liking, e.g. "Europe/Berlin".
+
 ## Finer granularity: The `/kiwi-cron/every` directory
 
 Directories like `/kiwi-cron/every/5_minutes` will run scripts every 5 minutes. 
diff --git a/libexec/kiwi-cron/run_cron b/libexec/kiwi-cron/run_cron
old mode 100644
new mode 100755
index 347aabb..8bfe7eb
--- a/libexec/kiwi-cron/run_cron
+++ b/libexec/kiwi-cron/run_cron
@@ -1,5 +1,9 @@
 #!/bin/sh
 
+# set timezone
+export TZ="${TZ:-Etc/UTC}"
+ln -sf "/usr/share/zoneinfo/${TZ}" "/etc/localtime"
+
 # check for CLI options
 while getopts ':n' rc_optarg; do
   case "${rc_optarg}" in