47_turn_watch.sh

#!/usr/bin/env bash
set -euo pipefail

URL="${1:-http://127.0.0.1:9641/metrics}"

echo "Watching $URL (CTRL-C to stop)"
prev_rx="" ; prev_tx=""
prev_t="$(date +%s)"

grab() {
  # first match of the counter; if multiple realms exist, this sums them
  curl -s "$URL" \
  | awk '
      /^turn_total_traffic_rcvb/ { rx+=$2 }
      /^turn_total_traffic_sentb/ { tx+=$2 }
      END { printf("%.0f %.0f\n", rx, tx) }
    '
}

while :; do
  now="$(date +%s)"
  read -r rx tx < <(grab || echo "0 0")
  if [[ -n "$prev_rx" ]]; then
    dt=$(( now - prev_t ))
    [[ $dt -lt 1 ]] && dt=1
    drx=$(( rx - prev_rx ))
    dtx=$(( tx - prev_tx ))
    rxbps=$(( drx / dt ))
    txbps=$(( dtx / dt ))
    printf "%s  RX: %8d B/s   TX: %8d B/s   (totals: RX=%d  TX=%d)\n" \
           "$(date +%H:%M:%S)" "$rxbps" "$txbps" "$rx" "$tx"
  fi
  prev_rx="$rx"; prev_tx="$tx"; prev_t="$now"
  sleep 1
done