infra/modules/apim/policies/api_policy_chargeback.xml

<policies>
    <inbound>
        <base/>
        <set-header name="X-Consumer" exists-action="override">
            <value>@( context.Subscription.Name )</value>
        </set-header>
        <set-backend-service backend-id="proxy-backend" />
    </inbound>
    <backend>
        <base/>
    </backend>
    <outbound>
        <base/>
        <!-- Dumping tracelogs for troubleshooting status 500 errors  -->
        <set-header name="X-OperationName" exists-action="override">
            <value>@( context.Operation.Name )</value>
        </set-header>
        <set-header name="X-OperationMethod" exists-action="override">
            <value>@( context.Operation.Method )</value>
        </set-header>
        <set-header name="X-OperationUrl" exists-action="override">
            <value>@( context.Operation.UrlTemplate )</value>
        </set-header>
        <set-header name="X-ApiName" exists-action="override">
            <value>@( context.Api.Name )</value>
        </set-header>
        <set-header name="X-ApiPath" exists-action="override">
            <value>@( context.Api.Path )</value>
        </set-header>
    </outbound>
    <on-error>
        <base/>
        <!-- Dumping tracelogs for troubleshooting status 500 errors  -->
        <set-header name="X-OperationName" exists-action="override">
            <value>@( context.Operation.Name )</value>
        </set-header>
        <set-header name="X-OperationMethod" exists-action="override">
            <value>@( context.Operation.Method )</value>
        </set-header>
        <set-header name="X-OperationUrl" exists-action="override">
            <value>@( context.Operation.UrlTemplate )</value>
        </set-header>
        <set-header name="X-ApiName" exists-action="override">
            <value>@( context.Api.Name )</value>
        </set-header>
        <set-header name="X-ApiPath" exists-action="override">
            <value>@( context.Api.Path )</value>
        </set-header>
        <set-header name="X-LastErrorMessage" exists-action="override">
            <value>@( context.LastError.Message )</value>
        </set-header>
    </on-error>
</policies>