#!/bin/bash
# The CI runner's window by hand, outside the night's (ADR 0039, D6): the heavy sidecars
# rested (halkyon-night), the runner started, every queued job run, then the runner
# stopped and the sidecars started again (halkyon-morning), however it ends. Jellyfin,
# the map, routes, place search, LanguageTool and the dictionaries are down meanwhile;
# --keep-sidecars keeps them, and the job runs slower beside them, in swap.
#
# Installed root's own by host step 7, never run from deploy's checkout (deploy could
# change it, and root runs it):
#   sudo install -m 755 deploy/runner/ci-now.sh /usr/local/sbin/halkyon-ci-now
# At the iMac:  sudo halkyon-ci-now [--keep-sidecars]
# From melchior, on its own on balthasar, so a closed laptop doesn't end it:
#   ssh -t balthasar sudo systemd-run --unit halkyon-ci-now /usr/local/sbin/halkyon-ci-now
#   ssh balthasar journalctl -fu halkyon-ci-now
#   ssh -t balthasar sudo systemctl stop halkyon-ci-now     # to end it early
set -euo pipefail

keep=false
case ${1:-} in
  '') ;;
  --keep-sidecars) keep=true ;;
  *)
    echo "usage: $0 [--keep-sidecars]" >&2
    exit 2
    ;;
esac
[ "$(id -u)" = 0 ] || { echo "Error: run it as root (sudo)" >&2; exit 1; }
if systemctl is-active --quiet forgejo-runner; then
  echo "The runner runs already (the night's window, or another start); nothing done." >&2
  exit 1
fi

restore() {
  trap - EXIT INT TERM HUP
  echo "== The runner stopped$($keep || echo ', the sidecars started again')"
  systemctl stop forgejo-runner || true
  $keep || systemctl start halkyon-morning
}
trap restore EXIT INT TERM HUP

if ! $keep; then
  echo "== The heavy sidecars rested"
  systemctl start halkyon-night
fi
echo "== The runner started; it stops itself after three hours at the latest"
systemctl start forgejo-runner

# The runner alone in its control group while idle; a job's processes beside it while
# one runs. Done once it has been idle for 90 s, several of its 10 s polls of the queue.
procs=/sys/fs/cgroup/system.slice/forgejo-runner.service/cgroup.procs
idle=0
jobs=0
running=false
while systemctl is-active --quiet forgejo-runner; do
  if [ "$(wc -l <"$procs")" -gt 1 ]; then
    $running || { jobs=$((jobs + 1)); echo "$(date +%H:%M) job $jobs running"; }
    running=true
    idle=0
  else
    $running && echo "$(date +%H:%M) job $jobs ended"
    running=false
    idle=$((idle + 10))
    [ "$idle" -ge 90 ] && break
  fi
  sleep 10
done
echo "== $jobs job(s) run; their results are in Forgejo, the repository's Actions"