Merge branch 'release/0.2.0'

Dockerfile

@@ -1,4 +1,5 @@
 FROM alpine:latest
+LABEL maintainer="jmm@yavook.de"
 
 ENV TZ=Etc/UTC
 
@@ -24,4 +25,4 @@ RUN set -ex; \
 COPY bin /usr/local/bin/
 COPY libexec /usr/local/libexec/
 
-CMD [ "kiwi-cron" ]
+CMD [ "kiwi-cron" ]

README.md

@@ -14,6 +14,12 @@ Just drop your scripts into the relevant directory under `/kiwi-cron`, that's it
 You will likely want to automate some tasks regarding your `docker` infrastructure. 
 That's why the `kiwi-cron` images package a current `docker-cli` – you can just mount your `docker.sock` in its containers and use `docker` commands normally.
 
+## 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".
+
 ## Simple jobs
 
 On startup, `kiwi-cron` checks for possible job files in the `/kiwi-cron` directory structure.
@@ -21,27 +27,21 @@ On startup, `kiwi-cron` checks for possible job files in the `/kiwi-cron` direct
 For each subdirectory, a random valid cron schedule is generated, so that:
 
 - `/kiwi-cron/hourly` runs once every hour (random minute)
-- `/kiwi-cron/daily` runs once every day (random nighttime value)
+- `/kiwi-cron/daily` runs once every day (random nighttime value between 9 pm and 3 am)
 - `/kiwi-cron/weekly` runs once every weekend (random nighttime value on Saturday or Sunday)
-- `/kiwi-cron/monthly` runs once every month (random nighttime value on a random day)
-- `/kiwi-cron/yearly` and `/kiwi-cron/annually` runs once a year (random nighttime value on a random day in January or February)
+- `/kiwi-cron/monthly` runs once every month (random nighttime value on a random day <= 28)
+- `/kiwi-cron/yearly` and `/kiwi-cron/annually` runs once a year (random nighttime value on a random day <= 28 in January or February)
 
 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
+## Granularity: The `/kiwi-cron/every` directory
 
 Directories like `/kiwi-cron/every/5_minutes` will run scripts every 5 minutes. 
 `kiwi-cron` picks up on that format and generates valid `cron` schedules on startup.
 
-You can define schedules to be run every N minutes, hours, days, or months by creating the corresponding directories. 
+This way, you can define schedules to be run every N minutes, hours, days, or months by creating the corresponding directories. 
 
-Scheduling for every N weeks (or years) doesn't work that way; jobs in those directories will instead be run every week (or every year).
+Scheduling for every N weeks (or years) doesn't work though; jobs in those directories will instead be run every week (or every year).
 
 ## Inspection
 

bin/kiwi-cron

@@ -2,4 +2,4 @@
 
 exec /usr/local/libexec/kiwi-cron/run_cron \
   "${@}" \
-  /usr/local/libexec/kiwi-cron/schedule_dirs
+  /usr/local/libexec/kiwi-cron/scheduler

libexec/kiwi-cron/create_schedule

@@ -4,50 +4,29 @@ cs_every="${1:-1}"
 cs_units="${2}"
 cs_command="${3}"
 
-if [ "${cs_every}" -eq 1 ]; then
-  cs_every=""
+if [ "${cs_every}" = "1" ]; then
+  cs_every="*"
 else
-  cs_every="/${cs_every}"
+  cs_every="*/${cs_every}"
 fi
 
-# generate valid random schedule values
-# generally, "nighttime" and "weekend" will be preferred.
-
-# shellcheck disable=SC3028 # RANDOM is defined in alpine's /bin/sh
-cs_rand_min=$(( RANDOM % 60 ))
-
-# shellcheck disable=SC3028
-# cs_rand_hour=$(( RANDOM % 24 ))
-cs_rand_hour=$(( (21 + RANDOM % 7) % 24 ))
-
-# shellcheck disable=SC3028
-cs_rand_day=$(( RANDOM % 31 + 1 ))
-
-# shellcheck disable=SC3028
-# cs_rand_weekday=$(( RANDOM % 7 ))
-cs_rand_weekday=$(( (6 + RANDOM % 2) % 7 ))
-
-# shellcheck disable=SC3028
-# cs_rand_month=$(( RANDOM % 12 + 1 ))
-cs_rand_month=$(( RANDOM % 2 + 1 ))
-
 case "${cs_units}" in
   minute)
-    echo "*${cs_every}" "*" "*" "*" "*" "${cs_command}" 
+    echo "${cs_every} * * * * ${cs_command}" 
     ;;
   hour)
-    echo "${cs_rand_min}" "*${cs_every}" "*" "*" "*" "${cs_command}" 
+    echo "R ${cs_every} * * * ${cs_command}" 
     ;;
   day)
-    echo "${cs_rand_min}" "${cs_rand_hour}" "*${cs_every}" "*" "*" "${cs_command}" 
+    echo "R R ${cs_every} * * ${cs_command}" 
     ;;
   week)
-    echo "${cs_rand_min}" "${cs_rand_hour}" "*" "*" "${cs_rand_weekday}" "${cs_command}" 
+    echo "R R * * R ${cs_command}" 
     ;;
   month)
-    echo "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "*${cs_every}" "*" "${cs_command}" 
+    echo "R R R ${cs_every} * ${cs_command}" 
     ;;
   year)
-    echo "${cs_rand_min}" "${cs_rand_hour}" "${cs_rand_day}" "${cs_rand_month}" "*" "${cs_command}" 
+    echo "R R R R * ${cs_command}" 
     ;;
 esac

libexec/kiwi-cron/print_crontab

@@ -1,28 +1,16 @@
 #!/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 \
+printf '%-8s%-8s%-8s%-8s%-8s%s\n' \
   "# 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}" 
+while read -r pc_minute pc_hour pc_day pc_month pc_weekday pc_command; do
+  printf '%-8s%-8s%-8s%-8s%-8s%s\n' \
+    "${pc_minute}" "${pc_hour}" "${pc_day}" "${pc_month}" "${pc_weekday}" "${pc_command}" 
 done

libexec/kiwi-cron/randomize_schedule

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+# shellcheck disable=SC3028 # RANDOM is defined in alpine's /bin/sh
+
+read -r rs_minute rs_hour rs_day rs_month rs_weekday rs_command
+
+[ "${rs_minute}" = "R" ] && \
+  rs_minute=$(( RANDOM % 60 ))
+
+[ "${rs_hour}" = "R" ] && \
+  rs_hour=$(( (21 + RANDOM % 6) % 24 ))   # prefer nighttime
+  # rs_hour=$(( RANDOM % 24 ))            # don't prefer nighttime
+
+[ "${rs_day}" = "R" ] && \
+  rs_day=$(( RANDOM % 28 + 1 ))           # don't mess with February 31st
+
+[ "${rs_month}" = "R" ] && \
+  rs_month=$(( RANDOM % 2 + 1 ))          # prefer January & February
+  # rs_month=$(( RANDOM % 12 + 1 ))       # don't prefer January & February
+
+[ "${rs_weekday}" = "R" ] && \
+  rs_weekday=$(( (6 + RANDOM % 2) % 7 ))  # prefer weekends
+  # rs_weekday=$(( RANDOM % 7 ))          # don't prefer weekends
+
+echo "${rs_minute} ${rs_hour} ${rs_day} ${rs_month} ${rs_weekday} ${rs_command}"

libexec/kiwi-cron/run_cron

@@ -1,5 +1,8 @@
 #!/bin/sh
 
+# commands
+crond_exe="$(command -v crond)"
+
 # set timezone
 export TZ="${TZ:-Etc/UTC}"
 ln -sf "/usr/share/zoneinfo/${TZ}" "/etc/localtime"
@@ -22,7 +25,6 @@ shift "$(( OPTIND - 1 ))"
 # CLI arguments
 rc_executable="${1}"
 
-
 if [ -n "${rc_dry_run}" ]; then
   # verbose, dry run
   set -x
@@ -39,6 +41,6 @@ fi
   | crontab -
 
 # hand over to crond
-exec crond -fd 8
+exec "${crond_exe}" -fd 8
 
-exit 0
+exit 0

libexec/kiwi-cron/scheduler

@@ -1,5 +1,7 @@
 #!/bin/sh
 
+# shellcheck disable=SC3001 # process substitution are defined in alpine's /bin/sh
+
 this_script="$( readlink -f "${0}" )"
 this_dir="${this_script%/*}"
 
@@ -42,7 +44,7 @@ schedule_dirs="$(
 )"
 
 for schedule_dir in ${schedule_dirs}; do
-  # ignore if no files
+  # ignore dirs without files
   if dir_has_no_files "${schedule_dir}"; then
     continue
   fi
@@ -52,7 +54,9 @@ for schedule_dir in ${schedule_dirs}; do
   units="${dir_name%ly}"
   units="$( dir_to_unit "${units}" )"
 
-  "${this_dir}/create_schedule" "1" "${units}" "run-parts '${schedule_dir}'"
+  "${this_dir}/create_schedule" \
+    "1" "${units}" "run-parts '${schedule_dir}'" \
+    | "${this_dir}/randomize_schedule"
 done
 
 # check dirs in "/kiwi-cron/every" directory
@@ -61,16 +65,29 @@ every_schedule_dirs="$(
 )"
 
 for schedule_dir in ${every_schedule_dirs}; do
-  # ignore if no files
+  # ignore dirs without files
   if dir_has_no_files "${schedule_dir}"; then
     continue
   fi
 
   # infer schedule params by directory name
   dir_name="${schedule_dir##*/}"
-  every="$( echo "${dir_name}" | awk -F_ '{print $1}' )"
-  units="$( echo "${dir_name}" | awk -F_ '{print $2}' )"
+  case "${dir_name}" in
+    *_*) # looks like: every/5_minutes
+      read -r every units < \
+        <( echo "${dir_name}" | tr '_' ' ' )
+      ;;
+
+    *) # probably looks like: every/day
+      every="1"
+      units="${dir_name}"
+      ;;
+  esac
+
+  # remove trailing "s" if present
   units="${units%s}"
 
-  "${this_dir}/create_schedule" "${every}" "${units}" "run-parts '${schedule_dir}'"
+  "${this_dir}/create_schedule" \
+    "${every}" "${units}" "run-parts '${schedule_dir}'" \
+    | "${this_dir}/randomize_schedule"
 done