# Manage Application-Defined Metadata Propagation

ESS adds support for [application-defined metadata/properties](https://docs.inrupt.com/ess/2.3/administration/application-defined-metadata) ; specifically, ESS adds support for [baggage HTTP header](https://www.w3.org/TR/baggage/) . These application-defined properties can be included in audit messages and log messages as well as returned as response headers. ESS further expands on this support by providing configuration to add non-baggage request headers to the baggage for propagation within its system.

{% hint style="info" %}
The client requests do not need to include a baggage header. If clients send only non-baggage request headers for application-defined properties (as determined by ESS configuration), ESS creates a baggage for propagation within its system. However, if a baggage request header exists, ESS adds the non-baggage requests headers (if any, as determined by ESS configuration) to the baggage, and propagates the enhanced baggage.
{% endhint %}

As part of its support for application-defined metadata propagation, ESS provides the following configurations to customize the propagation:

{% tabs %}
{% tab title="Allow Configurations" %}

| <p><strong><code>INRUPT\_REQUEST\_METADATA\_PROPAGATOR\_HEADER\_ALLOW</code></strong><br>Adds specified non-baggage request headers to the baggage for propagation (unless also specified in the corresponding <strong><code>\*\_DENY</code></strong> configuration); i.e., support propagation of non-baggage headers as application-defined properties. This configuration is case-<strong>insensitive</strong>.</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| <p><br><strong><code>INRUPT\_REQUEST\_METADATA\_REFLECTOR\_HEADER\_ALLOW</code></strong><br>Determines which propagated properties can be returned as<br>response headers (unless also specified in the<br>corresponding <strong><code>\*\_DENY</code></strong> configuration). This<br>configuration is case-<strong>sensitive</strong> to the entries in<br>the propagated baggage.</p><div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><p><strong>Tip</strong></p><ul><li>To return a propagated property that was added to the baggage via <strong><code>INRUPT\_REQUEST\_METADATA\_PROPAGATOR\_HEADER\_ALLOW</code></strong>, ensure that the cases of these properties match.</li><li>When returning application-properties as response headers, you may need to update <strong><code>QUARKUS\_HTTP\_CORS\_EXPOSED\_HEADERS</code></strong> to extend the list of <a href="https://developer.mozilla.org/en-US/docs/Glossary/CORS-safelisted_response_header">CORS-safelisted response headers</a></li></ul></div> |
| <p><br><strong><code>INRUPT\_LOGGING\_REQUEST\_METADATA\_ALLOW</code></strong><br>Determines which propagated properties can be included<br>in associated <a href="../../../../administration/logging#log-app-defined-metadata">log messages</a> (unless also specified in<br>the corresponding <strong><code>\*\_DENY</code></strong> configuration). This<br>configuration is case-<strong>sensitive</strong> to the propagated<br>baggage entries.</p><div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><p>To include a propagated property that was added to the baggage via <strong><code>INRUPT\_REQUEST\_METADATA\_PROPAGATOR\_HEADER\_ALLOW</code></strong>, ensure that the cases of these properties match.</p></div>                                                                                                                                                                                                                                                                                           |
| <p><strong><code>INRUPT\_AUDIT\_PRODUCER\_REQUEST\_METADATA\_ALLOW</code></strong><br>Determines which propagated properties can be included<br>in associated <a href="../../../../services/service-auditing#event-message-instrument-app-defined-metadata">audit events</a><br>(unless also specified in the corresponding <strong><code>\*\_DENY</code></strong><br>configuration). This configuration is<br>case-<strong>sensitive</strong> to the propagated baggage entries.</p><div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><p><strong>Tip</strong><br>To include a propagated property that was added to the baggage via <strong><code>INRUPT\_REQUEST\_METADATA\_PROPAGATOR\_HEADER\_ALLOW</code></strong>, ensure that the cases of these properties match.</p></div>                                                                                                                                                                                                                                       |
| {% endtab %}                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |

{% tab title="Deny Configurations" %}

| <p><strong><code>INRUPT\_REQUEST\_METADATA\_PROPAGATOR\_HEADER\_DENY</code></strong><br>Excludes specified non-baggage request headers from being<br>added to the baggage.<br>This configuration is case-<strong>insensitive</strong>.</p>                                                                                                                                                                                                                                                                                                                                                                 |
| ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| <p><br><strong><code>INRUPT\_REQUEST\_METADATA\_REFLECTOR\_HEADER\_DENY</code></strong><br>Excludes propagated properties from returning as<br>response headers. This configuration is case-<strong>sensitive</strong><br>to the entries in the propagated baggage.</p><div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><p><strong>Tip</strong><br>To exclude a propagated property that was added to the baggage via <strong><code>INRUPT\_REQUEST\_METADATA\_PROPAGATOR\_HEADER\_ALLOW</code></strong>, ensure that the cases of these properties match.</p></div>     |
| <p><strong><code>INRUPT\_LOGGING\_REQUEST\_METADATA\_DENY</code></strong><br>Excludes propagated properties from being included in<br>associated log messages. This configuration is<br>case-<strong>sensitive</strong> to the propagated<br>baggage entries.</p><div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><p><strong>Tip</strong><br>To exclude a propagated property that was added to the baggage via <strong><code>INRUPT\_REQUEST\_METADATA\_PROPAGATOR\_HEADER\_ALLOW</code></strong> , ensure that the cases of these properties match.</p></div>          |
| <p><strong><code>INRUPT\_AUDIT\_PRODUCER\_REQUEST\_METADATA\_DENY</code></strong><br>Determines which propagated properties are included in<br>associated audit events. This configuration is<br>case-<strong>sensitive</strong> to the propagated<br>baggage entries.</p><div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><p><strong>Tip</strong><br>To exclude a propagated property that was added to the baggage via <strong><code>INRUPT\_REQUEST\_METADATA\_PROPAGATOR\_HEADER\_ALLOW</code></strong> , ensure that the cases of these properties match.</p></div> |
| {% endtab %}                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |

{% tab title="Miscellaneous" %}
**`INRUPT_REQUEST_METADATA_PROPAGATOR_HEADER_OVERRIDES`**\
Determines, in cases of a property being defined both\
as a header and as a baggage entry, whether to keep\
the entry or update/override it with the header value.\
The default is to keep the baggage entry as is. See [Duplicate Property Definition](https://docs.inrupt.com/ess/administration/application-defined-metadata#duplicate-property-definition) for more\
information.
{% endtab %}
{% endtabs %}

## Example Customization

The following example configuration updates:

* **`INRUPT_REQUEST_METADATA_PROPAGATOR_HEADER_ALLOW`** to include the client request **`x-correlation-id`** , **`x-request-id`** , and **`my-client-version`** headers as baggage entries.
* **`INRUPT_LOGGING_REQUEST_METADATA_ALLOW`** to include the propagated **`x-correlation-id`** , **`x-request-id`** , and **`my-client-version`** in the associated log messages.
* **`INRUPT_AUDIT_PRODUCER_REQUEST_METADATA_ALLOW`** to include the propagated **`x-correlation-id`** , **`x-request-id`** , and **`my-client-version`** in the associated audit events.
* **`INRUPT_LOGGING_REQUEST_METADATA_ALLOW`** to return the propagated **`x-correlation-id`** and **`x-request-id`** as response headers (and not **`my-client-version`**).

{% hint style="info" %}
**Tip** **`INRUPT_LOGGING_REQUEST_METADATA_ALLOW`** , **`INRUPT_AUDIT_PRODUCER_REQUEST_METADATA_ALLOW`** , and **`INRUPT_REQUEST_METADATA_REFLECTOR_HEADER_ALLOW`** are case- **sensitive** to the entries in the propagated baggage. If the propagated baggage includes properties from **`INRUPT_REQUEST_METADATA_PROPAGATOR_HEADER_ALLOW`** configuration, ensure that the cases of those properties match.
{% endhint %}

1. Go to your ESS installation directory:

   ```sh
   cd ${HOME}/ess
   ```
2. Modify the **`kustomization.yaml`** (i.e., step 3 of the [Applying Your Customizations](https://docs.inrupt.com/ess/2.3/installation/customize-configurations/..#applying-your-customizations) procedure).\
   Specifically, add the highlighted content to the **`kustomization.yaml`** file under the **`patches`** key:

{% hint style="info" %}
**Tip** If **`patches`** list does not exist in **`kustomization.yaml`** , add the key **`patches`** as well.
{% endhint %}

```yaml
# kustomization.yaml in your ESS installation directory
# ...  Preceding content omitted for brevity 
# ...
patches:
  - target:
      kind: Deployment
      labelSelector: quarkus=true
    patch: |-
      - op: add
        path: /spec/template/spec/containers/0/env/-
        value:
          #Adds the following request headers to the `baggage` for propagation
          name: INRUPT_REQUEST_METADATA_PROPAGATOR_HEADER_ALLOW
          value:"x-correlation-id,x-request-id,my-client-version"
      - op: add
        path: /spec/template/spec/containers/0/env/-
        value:
          #Return the following propagated properties as response headers
          name: INRUPT_REQUEST_METADATA_REFLECTOR_HEADER_ALLOW
          value: "x-correlation-id,x-request-id"
      - op: add
        path: /spec/template/spec/containers/0/env/-
        value:
          #Include the following propagated properties in log messages
          name: INRUPT_LOGGING_REQUEST_METADATA_ALLOW
          value: "x-correlation-id,x-request-id,my-client-version,"
      - op: add
        path: /spec/template/spec/containers/0/env/-
        value:
          #Include the following propagated properties in audit events
          name: INRUPT_AUDIT_PRODUCER_REQUEST_METADATA_ALLOW
          value: "x-correlation-id,x-request-id,my-client-version"

```

{% hint style="info" %}
**Tip** When returning application-defined properties as response headers, you may need to update **`QUARKUS_HTTP_CORS_EXPOSED_HEADERS`** to extend the list of [CORS-safelisted response headers](https://developer.mozilla.org/en-US/docs/Glossary/CORS-safelisted_response_header) .
{% endhint %}

3. Continue with the rest of the [Applying Your Customizations](https://docs.inrupt.com/ess/2.3/installation/customize-configurations/..#applying-your-customizations) procedure.