files/scripts: run-roverlay.sh

Safely run overlay creation (abort if another process is already running).
This can be used to set up a cron job.

1 files changed, 93 insertions, 0 deletions

diff --git a/files/scripts/run-roverlay.sh b/files/scripts/run-roverlay.sh
new file mode 100755
index 0000000..0ce26b4
--- /dev/null
+++ b/files/scripts/run-roverlay.sh
@@ -0,0 +1,93 @@
+#!/usr/bin/roverlay-sh
+#
+# This script runs R overlay creation and repoman afterwards.
+#
+# It will exit immediately if another instance is already running.
+# To achieve this, filesystem locks are used (/run/lock/roverlay.lock).
+#
+# So, it's safe to set up a cronjob that calls this script.
+#
+set -u
+
+# reset DEBUG, VERBOSE, QUIET
+DEBUG=n; QUIET=n; VERBOSE=y
+
+LC_COLLATE=C
+
+. "${FUNCTIONS?}" || exit 9
+
+readonly MY_LOCK=/run/lock/roverlay
+MY_LOCK_PID=
+
+# void run__cleanup ( **MY_LOCK_PID!, **MY_LOCK )
+#
+#  Atexit function that releases the lock.
+#
+run__cleanup() {
+   # release trap
+   trap - INT TERM EXIT
+
+   # release lock
+   if [ -n "${MY_LOCK_PID-}" ]; then
+      kill "${MY_LOCK_PID}"
+      wait "${MY_LOCK_PID}" 2>>${DEVNULL} && MY_LOCK_PID=
+   fi
+   lockfile-remove "${MY_LOCK}" || true
+}
+
+
+# prepare:
+
+# (TODO)
+REPOMAN_ARGS="--pretend full"
+
+WANT_ROVERLAY_CREATE=y
+WANT_ROVERLAY_SYNC=y
+WANT_REPOMAN=y
+
+#  parse args
+doshift=1
+while [ $# -gt 0 ]; do
+   case "${1?}" in
+      '+C'|'--no-create') WANT_ROVERLAY_CREATE=n ;;
+      '+S'|'--no-sync') WANT_ROVERLAY_SYNC=n ;;
+      '+R'|'--no-repoman') WANT_REPOMAN=n ;;
+      *)
+         die "unknown arg: ${1}" ${EX_ARG_ERR?}
+      ;;
+   esac
+   shift ${doshift} || OUT_OF_BOUNDS
+   doshift=1
+done
+unset -v doshift
+
+# anything to do?
+
+# main:
+#
+#  anything to do? acquire lock
+if ! list_has y \
+   "${WANT_ROVERLAY_CREATE}" "${WANT_ROVERLAY_SYNC}" "${WANT_REPOMAN}"
+then
+   die 'nothing to do' 2
+elif lockfile-create --retry 0 "${MY_LOCK}" 2>>${DEVNULL}; then
+   # hold lock until done
+   lockfile-touch "${MY_LOCK}" &
+   MY_LOCK_PID="$!"
+   trap run__cleanup INT TERM EXIT
+
+   roverlay_opts=""
+   roverlay_opts() { roverlay_opts="${roverlay_opts-}${roverlay_opts:+ }$*"; }
+
+   ! yesno "${WANT_ROVERLAY_SYNC}" || roverlay_opts "--nosync"
+
+   # run roverlay
+   if ${ROVERLAY_EXE} ${roverlay_opts}; then
+      # success, continue with repoman
+      if yesno "${WANT_REPOMAN}"; then
+         ( cd "${S}" && repoman ${REPOMAN_ARGS} 2>&1 1>"${WORKDIR}/repoman.log"; )
+      fi
+   fi
+else
+   die "another instance is already running" 0
+fi