Error Tolerance

Tirith supports error tolerance to handle missing or invalid keys in the input JSON.

Handling Missing Keys

If a key referenced in an evaluator is missing, the evaluation typically fails. However, setting error_tolerance allows evaluators to be skipped instead of failing.

If we modify the previous policy to include error_tolerance, missing keys won’t cause a failure:

policy.json

{
  // ...
  "id": "can_post",
  "provider_args": {
    "operation_type": "get_value",
    "key_path": "verb"
  },
  "condition": {
    "type": "Equals",
    "value": "POST",
    "error_tolerance": 2
  }
  // ...
}

This ensures that if verb is missing, the evaluation is skipped rather than failing.