是在 Twitter 上看到這個：
Introducing the new phpBB Status Site https://t.co/V20jmQk4Px
— phpBB (@phpbb) May 8, 2022
然後翻到 Upptime 這個 open source monitoring 工具，直接是用 GitHub Actions 提供的 schedule (cron job) 每五分鐘跑一次。這邊要注意的是，如果是 public repository 的話不受限制，如果是 private repository 的話會有機會把 quota 吃完：
Billing note: Upptime uses thousands of build minutes every month (approximately 3,000 minutes in the default setting). If you use a public repository, GitHub offers unlimited free build minutes, but if you use a private repository, you'll have to pay for this time.
依照說明是用 GitHub Actions、GitHub Issues、GitHub Pages 三個功能在運作：
- GitHub Actions is used as an uptime monitor
- GitHub Issues are used for incident reports
- GitHub Pages are used for the status website
除了用這三個功能外，另外還是會每天塞一些資料回 git history 裡面：
We also record the response time once per day and commit it to git history. This way, we can graph long-term trends in your websites' response times by going through git commit history. We generate these graphs once every day, also using schedulers.
好像可以玩看看...