--- title: Denier overview: Adapter that always returns a precondition denial. location: https://istio.io/docs/reference/config/adapters/denier.html layout: protoc-gen-docs number_of_entries: 2 ---

The `denier` adapter is designed to always return a denial to precondition checks. You can specify the exact error to return for these denials.

## Params

Configuration format for the Denier adapter.

Field | Type | Description
--- | --- | ---
`status` | `google.rpc.Status` | The error to return when denying a request.
`validDuration` | `google.protobuf.Duration` | The duration for which the denial is valid.
`validUseCount` | `int32` | The number of times the denial may be used.

## google.rpc.Status

The `Status` type defines a logical error model that is suitable for different programming environments, including REST APIs and RPC APIs. It is used by gRPC. The error model is designed to be:

- Simple to use and understand for most users
- Flexible enough to meet unexpected needs

### Overview

The `Status` message contains three pieces of data: error code, error message, and error details. The error code should be an enum value of google.rpc.Code, but it may accept additional error codes if needed. The error message should be a developer-facing English message that helps developers understand and resolve the error. If a localized user-facing error message is needed, put the localized message in the error details or localize it in the client. The optional error details may contain arbitrary information about the error. There is a predefined set of error detail types in the package `google.rpc` that can be used for common error conditions.

### Language mapping

The `Status` message is the logical representation of the error model, but it is not necessarily the actual wire format. When the `Status` message is exposed in different client libraries and different wire protocols, it can be mapped differently. For example, it will likely be mapped to some exceptions in Java, but more likely mapped to some error codes in C.

### Other uses

The error model and the `Status` message can be used in a variety of environments, either with or without APIs, to provide a consistent developer experience across different environments.

Example uses of this error model include:

- Partial errors. If a service needs to return partial errors to the client, it may embed the `Status` in the normal response to indicate the partial errors.

- Workflow errors. A typical workflow has multiple steps. Each step may have a `Status` message for error reporting.

- Batch operations. If a client uses batch request and batch response, the `Status` message should be used directly inside batch response, one for each error sub-response.

- Asynchronous operations. If an API call embeds asynchronous operation results in its response, the status of those operations should be represented directly using the `Status` message.

- Logging. If some API errors are stored in logs, the message `Status` could be used directly after any stripping needed for security/privacy reasons.

Field | Type | Description
--- | --- | ---
`code` | `int32` | The status code, which should be an enum value of google.rpc.Code.
`message` | `string` | A developer-facing error message, which should be in English. Any user-facing error message should be localized and sent in the google.rpc.Status.details field, or localized by the client.
`details` | `google.protobuf.Any[]` | A list of messages that carry the error details. There is a common set of message types for APIs to use.