keepalive.yml

name: keep-streamlit-awake

# Streamlit Community Cloud (free tier) sleeps an app after ~12h of no traffic, so the
# next visitor hits a "wake up" screen + a cold start. This pings the app's health
# endpoint every few hours to keep the container warm for public viewers.
# Note: this lightly bends the free tier's intent; the fully-professional path is a small
# always-on host (see the README). Best-effort — Streamlit may still recycle the container.
on:
  schedule:
    - cron: "23 */6 * * *"   # every ~6 hours, off-the-hour on purpose
  workflow_dispatch: {}

permissions:
  contents: read

jobs:
  ping:
    runs-on: ubuntu-latest
    steps:
      - name: Wake / keep the app warm
        run: |
          APP="https://tfl-data-engineering.streamlit.app"
          # Health endpoint returns "ok" when the app is serving; also hit root to trigger a wake.
          curl -fsS --retry 5 --retry-all-errors --max-time 60 "$APP/_stcore/health" || true
          curl -fsS --retry 5 --retry-all-errors --max-time 60 "$APP/" -o /dev/null || true
          echo "pinged $APP"