#!/usr/bin/env bash
# Keep the Streamlit app alive on port 8599.
#
# The server (or the machine) can drop it at any time, so every 5 minutes
# this checks whether something is answering on the port and, if not,
# relaunches it detached. Streamlit only hot-reloads app.py, so module
# changes need this relaunch (or a manual one) to take effect.
#
# Usage: setsid nohup fundlab/server_watchdog.sh </dev/null >>fundlab/server_watchdog.log 2>&1 &
set -u
cd "$(dirname "$0")/.."
PORT=8599
INTERVAL=300

alive() {
  curl -s -o /dev/null --max-time 8 "http://127.0.0.1:${PORT}/_stcore/health" \
    && [ "$(curl -s --max-time 8 "http://127.0.0.1:${PORT}/_stcore/health")" = "ok" ]
}

while true; do
  if ! alive; then
    { date "+%Y-%m-%d %H:%M:%S"
      echo "server_watchdog: no answer on :${PORT} - relaunching"
    } >> fundlab/server_watchdog.log
    setsid nohup .venv/bin/streamlit run app.py \
      --server.port "${PORT}" --server.headless true \
      --browser.gatherUsageStats false >> fundlab/streamlit.log 2>&1 < /dev/null &
    sleep 15
  fi
  sleep "${INTERVAL}"
done