---
layout: docs
page_title: Property override configuration reference
description: Learn how to configure the property-override plugin, which is a builtin Consul plugin that allows you to set and remove Envoy proxy properties.
---

# Property override configuration reference

This topic describes how to configure the `property-override` extension so that you can set and remove individual properties on the Envoy resources Consul generates. Refer to [Configure Envoy proxy properties](/consul/docs/envoy-extension/property-override) for usage information.

## Configuration model

The following list outlines the field hierarchy, data types, and requirements for the `property-override` configuration. Place the configuration inside the `EnvoyExtension.Arguments` field in the proxy defaults or service defaults configuration entry. Refer the following documentation for additional information:

- [`EnvoyExtensions` in proxy defaults](/consul/docs/reference/config-entry/proxy-defaults#envoyextensions)
- [`EnvoyExtensions` in service defaults](/consul/docs/reference/config-entry/service-defaults#envoyextensions)

Click on a property name to view additional details, including default values.
  
- [`ProxyType`](#proxytype): string | `connect-proxy`
- [`Debug`](#debug): bool | `false` 
- [`Patches`](#patches): list | required
   - [`ResourceFilter`](#patches-resourcefilter): map         
      - [`ResourceType`](#patches-resourcefilter-resourcetype): string | required
      - [`TrafficDirection`](#patches-resourcefilter-trafficdirection): string | required
      - [`Services`](#patches-resourcefilter-services): list
         - [`Name`](#patches-resourcefilter-services-name): string
         - [`Namespace`](#patches-resourcefilter-services-namespace): string | `default` | <EnterpriseAlert inline/>
         - [`Partition`](#patches-resourcefilter-services-partition): string | `default` | <EnterpriseAlert inline/>
   - [`Op`](#patches-op): string | required
   - [`Path`](#patches-path): string | required
   - [`Value`](#patches-value): map, number, boolean, or string

## Complete configuration

When each field is defined, a `property-override` configuration has the following form:


```hcl
ProxyType = "connect-proxy"
Debug = false
Patches = [
  {
    ResourceFilter = {
      ResourceType = "<type of resource>"
      TrafficDirection = "<inbound or outbound>"
      Services = [
        {
          Name = "<name of service to filter for>"
          Namespace = "<Consul namespace containing the service>"
          Partition = "<Consul partition containing the service>"
        }
      ]
    }
    Op = "<add or remove>"
    Path = "</path/to/field>"
    Value = "<values or map of field-values>"
  }
]
```       

## Specification

This section provides details about the fields you can configure for the `property-override` extension.

### `ProxyType`

Specifies the type of Envoy proxy that the extension applies to. The only supported value is `connect-proxy`.

#### Values

- Default: `connect-proxy`
- Data type: String 

### `Debug`

Enables full debug mode. When `Debug` is set to `true`, all possible fields for the given `ResourceType` and first unmatched segment of `Path` are returned on error. When set to `false`, the error message only includes the first ten possible fields. 

#### Values

- Default: `false`
- Data type: Boolean

### `Patches[]`

Specifies a list of one or more JSON Patches that map to the Envoy proxy configurations you want to modify. Refer to [IETF RFC 6902](https://datatracker.ietf.org/doc/html/rfc6902/) for information about the JSON Patch specification. 

#### Values

- Default: None
- The `Patches` parameter is a list of configurations in JSON Patch format. Each patch can contain the following fields:
   - [`ResourceFilter`](#patches-resourcefilter)
   - [`Op`](#patches-op)
   - [`Path`](#patches-path)
   - [`Value`](#patches-value)


### `Patches[].ResourceFilter{}`

Specifies the filter for targeting specific Envoy resources. The `ResourceFilter` configuration is not part of the JSON Patch specification. 

#### Values

- Default: None
- This field is required.
- Data type: Map

The following table describes how to configure a `ResourceFilter`:

| Parameter | Description | Type |
| ---       | ---         | ---  |
| `ProxyType` | Specifies the proxy type that the extension applies to. The only supported value is `connect-proxy`. | String |
| `ResourceType` | Specifies the Envoy resource type that the extension applies to. You can specify one of the following values for each `ResourceFilter`: <ul><li>`cluster`</li><li>`cluster-load-assignment`</li><li>`route`</li><li>`listener`</li></ul> | String |
| `TrafficDirection` | Specifies the type of traffic that the extension applies to relative to the current proxy. You can specify one of the following values for each `ResourceFilter`: <ul><li>`inbound`: Targets resources for the proxy's inbound traffic.</li> <li>`outbound`: Targets resources for the proxy's upstream services.</li></ul> | String |
| `Services` | Specifies a list of services to target. Each member of the list has the following fields:<ul><li>`Name`: Specifies the service associated with the traffic.</li><li>`Namespace`: Specifies the Consul Enterprise namespace the service is in.</li><li>`Partition`: Specifies the Consul Enterprise admin partition the service is in.</li> </ul>If `TrafficDirection` is set to `outbound`, upstream services in this field correspond to local Envoy resources that Consul patches at runtime. <p>Do not configure the `Services` field if `TrafficDirection` is set to `inbound`.</p> If this field is not set, Envoy targets all applicable resources. When patching outbound listeners, the patch includes the outbound transparent proxy listener only if `Services` is unset and if the local service is in transparent proxy mode. | List of maps |

### `Patches[].Op`

Specifies the JSON Patch operation to perform when the `ResourceFilter` matches a local Envoy proxy configuration. You can specify one of the following values for each patch:

- `add`: Replaces a property or message specified by [`Path`](#patches-path) with the given value. The JSON Patch `add` operation does not merge objects. To emulate merges, you must configure discrete `add` operations for each changed field. Consul returns an error if the target field does not exist in the corresponding schema.
- `remove`: Unsets the value of the field specified by [`Path`](#patches-path). If the field is not set, no changes are made. Consul returns an error if the target field does not exist in the corresponding schema.

#### Values

- Default: None
- This field is required.
- Data type is one of the following string values:
   - `add`
   - `remove`

### `Patches[].Path`

Specifies where the extension performs the associated operation on the specified resource type. Refer to [`ResourceType`](#patches-resourcefilter) for information about specifying a resource type to target. Refer to [`Op`](#patches-op) for information about setting an operation to perform on the resources. 

The `Path` field does not support addressing array elements or protobuf map field entries. Refer to [Constructing paths](/consul/docs/connect/proxies/envoy-extensions/usage/property-override#constructing-paths) for information about how to construct paths. 

When setting fields, the extension sets any unset intermediate fields to their default values. A single operation on a nested field can set multiple intermediate fields. Because Consul sets the intermediate fields to their default values, you may need to configure subsequent patches to satisfy Envoy or Consul validation. 

#### Values

- Default: None
- This field is required.
- Data type: String

### `Patches[].Value{}`

Defines a value to set at the specified [path](#patches-path) if the [operation](#patches-op) is set to `add`. You can specify either a scalar or enum value, an array of scalar or enum values (for repeated fields), or define a map that contains string keys and values corresponding to scalar or enum child fields. Single and repeated scalar and enum values are supported. Refer to the [example configurations](#examples) for additional guidance and to the [Envoy API documentation](https://www.envoyproxy.io/docs/envoy/latest/api-v3/api) for additional information about Envoy proxy interfaces.

If Envoy specifies a wrapper as the target field type, the extension automatically coerces simple values to the wrapped type when patching. For example, the value `32768` is allowed when targeting a cluster's `per_connection_buffer_limit_bytes`, which is a `UInt32Value` field. Refer to the [protobuf documentation](https://github.com/protocolbuffers/protobuf/blob/main/src/google/protobuf/wrappers.proto) for additional information about wrappers.

#### Values

- Default: None
- This field is required if [`Op`](#patches-op) is set to `add`, otherwise you must omit the field.
- This field takes one of the following data types:
   - scalar
   - enum
   - map 

## Examples

The following examples demonstrate patterns that you may be able to model your configurations on.

### Enable `respect_dns_ttl` in a cluster

In the following example, the `add` operation patches the outbound cluster corresponding to the `other-svc` upstream service to enable `respect_dns_ttl`. The `Path` specifies the [Cluster `/respect_dns_ttl`](https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/cluster/v3/cluster.proto#envoy-v3-api-field-config-cluster-v3-cluster-respect-dns-ttl) top-level field and `Value` specifies a value of `true`:

```hcl
Kind = "service-defaults"
Name = "my-svc"
Protocol = "http"
EnvoyExtensions = [
  {
    Name = "builtin/property-override",
    Arguments = {
      ProxyType = "connect-proxy",
      Patches = [
        {
          ResourceFilter = {
            ResourceType = "cluster"
            TrafficDirection = "outbound"
            Service = {
              Name = "other-svc"
            }
          }
          Op = "add"
          Path =  "/respect_dns_ttl"
          Value = true
        }
      ]
    }
  }
]
```

### Update multiple values in a message field

In the following example, both `ResourceFilter` blocks target the cluster corresponding to the `other-svc` upstream service and modify [Cluster `/outlier_detection`](https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/cluster/v3/outlier_detection.proto) properties:

```hcl
Kind = "service-defaults"
Name = "my-svc"
Protocol = "http"
EnvoyExtensions = [
  {
    Name = "builtin/property-override",
    Arguments = {
      ProxyType = "connect-proxy",
      Patches = [
        {
          ResourceFilter = {
            ResourceType = "cluster"
            TrafficDirection = "outbound"
            Services = [{
              Name = "other-svc"
            }]
          }
          Op = "add"
          Path = "/outlier_detection/max_ejection_time/seconds"
          Value = 120
        },
        {
          ResourceFilter = {
            ResourceType = "cluster"
            TrafficDirection = "outbound"
            Services = [{
              Name = "other-svc"
            }]
          }
          Op = "add"
          Path = "/outlier_detection/max_ejection_time_jitter/seconds"
          Value = 1
        }
      ]
    }
  }
]
```

The use of `/seconds` in these examples corresponds to the same field in the [google.protobuf.Duration](https://github.com/protocolbuffers/protobuf/blob/main/src/google/protobuf/duration.proto) proto definition, since the extension does not support JSON serialized string forms of common protobuf types (e.g. `120s`).

-> **Note:** Using separate patches per field preserves any existing configuration of other fields in `outlier_detection` that may be directly set by Consul, such as [`enforcing_consecutive_5xx`](https://developer.hashicorp.com/consul/docs/connect/proxies/envoy#enforcing_consecutive_5xx).

### Replace a message field

In the following example, a `ResourceFilter` targets the cluster corresponding to the `other-svc` upstream service and _replaces_ the entire map of properties located at `/outlier_detection`, including explicitly set `enforcing_success_rate` and `success_rate_minimum_hosts` properties:

```hcl
Kind = "service-defaults"
Name = "my-svc"
Protocol = "http"
EnvoyExtensions = [
  {
    Name = "builtin/property-override"
    Arguments = {
      ProxyType = "connect-proxy"
      Patches = [
        {
          ResourceFilter = {
            ResourceType = "cluster"
            TrafficDirection = "outbound"
            Services = [{
              Name = "other-svc"
            }]
          }
          Op = "add"
          Path =  "/outlier_detection"
          Value = {
            "enforcing_success_rate" = 80
            "success_rate_minimum_hosts" = 2
          }
        }
      ]
    }
  }
]
```

Unlike the previous example, other `/outlier_detection` values set by Consul will _not_ be retained unless they match Envoy's defaults, because the entire value of `/outlier_detection` will be replaced.
