{
  "name": "derive_overwrites_an_existing_value",
  "description": "derive is a set, not an insert-if-absent.",
  "rules": [
    {
      "match": [],
      "actions": [
        {
          "action": "derive",
          "field": "attributes.env",
          "value": "dev"
        }
      ]
    }
  ],
  "inputs": [
    {
      "timestamp_unix_nano": 1000,
      "host": "h1",
      "service": "s1",
      "severity": "SEVERITY_INFO",
      "message": "a",
      "attributes": {
        "env": "prod"
      }
    }
  ],
  "expect": [
    {
      "timestamp_unix_nano": 1000,
      "host": "h1",
      "service": "s1",
      "severity": "SEVERITY_INFO",
      "message": "a",
      "attributes": {
        "env": "dev"
      }
    }
  ]
}