start.json

{
  "daemon": true,
  "run": [{
    "method": "shell.run",
    "params": {
      "venv": "env",
      "message": "python app.py",
      "on": [{
        "event": "/http://[0-9.:]+/",
        "done": true
      }]
    }
  }, {
    "method": "local.set",
    "params": {
      "url": "{{input.event[0]}}"
    }
  }]
}