#!/usr/bin/env bash
# KNELPerf PSI (pressure stall info) avg60 -> node_exporter textfile collector.
# Ported from ultix staged/ukrrs-psi-textfile.sh (#826); generalizations:
#   - cgroup glob is env-driven (any slice namespace, not just ukrrs-*)
#   - metric prefix is env-driven (default knelperf_)
set -u
OUT_DIR=${KNELPERF_TEXTFILE_DIR:-/var/lib/node_exporter/textfile}
CGROOT=${KNELPERF_CGROOT:-/sys/fs/cgroup}
CG_GLOB=${KNELPERF_CG_GLOB:-"$CGROOT"/system.slice/knelperf-*.slice}
PREFIX=${KNELPERF_PREFIX:-knelperf}
mkdir -p "$OUT_DIR"
tmp=$(mktemp "$OUT_DIR/.knelperf.XXXXXX")

some60() { # file -> prints avg60 value or nothing
  awk '$1=="some"{for(i=2;i<=NF;i++) if($i ~ /^avg60=/){sub("avg60=","",$i); print $i; exit}}' "$1" 2>/dev/null
}

emit() { # name cgroup_path
  local res v
  for res in cpu memory io; do
    [ -r "$2/$res.pressure" ] || continue
    v=$(some60 "$2/$res.pressure")
    [ -n "${v:-}" ] && echo "${PREFIX}_slice_pressure_some60{slice=\"$1\",res=\"$res\"} $v"
  done
}

echo "# HELP ${PREFIX}_slice_pressure_some60 PSI some avg60 (percent) per slice" >>"$tmp"
echo "# TYPE ${PREFIX}_slice_pressure_some60 gauge" >>"$tmp"
for cg in $CG_GLOB; do
  [ -d "$cg" ] && emit "${cg##*/}" "$cg"
done
[ -d "$CGROOT/user.slice" ] && emit "user.slice" "$CGROOT/user.slice"

echo "# HELP ${PREFIX}_host_pressure_some60 PSI some avg60 (percent) host-wide" >>"$tmp"
echo "# TYPE ${PREFIX}_host_pressure_some60 gauge" >>"$tmp"
for res in cpu memory io; do
  [ -r "/proc/pressure/$res" ] || continue
  v=$(some60 "/proc/pressure/$res")
  [ -n "${v:-}" ] && echo "${PREFIX}_host_pressure_some60{res=\"$res\"} $v"
done

mv "$tmp" "$OUT_DIR/${PREFIX}_pressure.prom"
chmod 0644 "$OUT_DIR/${PREFIX}_pressure.prom"