Contact Us 1-800-596-4880
  1. Homepage
  2. Mule Gateway
  3. Policies in Mule 3
  4. Custom Policies

  5. Configuration and Definition File Reference

Configuration and Definition File Reference

Find a complete technical reference for the configuration (XML) and definition (YAML) file for creating a custom policy.

Policy Configuration XML File

The policy configuration is an XML file that implements the actual execution of the policy. The configuration achieves this by leveraging the elements in a flow when creating a Mule Runtime application. All of the elements usable in Mule Runtime can be used in a custom policy.

The policy configuration defines the actual processes that carry out the implementation of the policy. Structured like a Mule app, you wrap content in the following tags:

<policy>
</policy>

The opening <policy> tag includes references to all of the Mule XSD files used in the policy. Some of the Mule elements you can add require adding the corresponding XSD reference too.

You add properties id and policyName to the <policy> element parameters to gather data about the API for analytics.

By default, when you create a custom policy, you have access to the following default configuration properties that you can reference in the configuration XML file:

Property Description

policyId

A unique ID for the current policy

endpointUri

The full URI for the inbound endpoint of the API

apiId

Unique ID number for the API

apiVersionId

Unique ID number for the API version

apiName

Name of the API

isRamlEndpoint

Boolean that determines if the endpoint is linked to a RAML definition file

isWsdlEndpoint

Boolean that determines if the endpoint is linked to a WSDL definition file

isHttpEndpoint

Boolean that determines if the endpoint follows the HTTP protocol

In addition to these default properties, you can specify new ones in the policy definition YAML file and reference them in the policy configuration XML file.

Policy Tag Properties

The policy tag properties are important parts of a custom policy XML configuration:

  • order property in the <policy> tag

  • order property in the <before></before>and <after></after>

These properties determine the order of execution of policies.

The requiresContracts property is critical for client validation.

The Custom Policy Properties Reference contains more information about these properties.

In the configuration XML of a custom policy, you can access the default set of properties for a policy definition and properties defined in the Policy Template YAML file. To reference a property, type its name enclosed in two curly brackets as follows:

{{propertyName}}

This topic covers the order and requiresContracts properties.

Order Property in Policy Tag

You can set the order of execution of a policy using the order property, however, setting the order of policy execution in a message processor takes precedence over setting the order of execution in the policy tag. Set the order to an integer greater than 2 because the order values 0 - 2 are reserved for CORS, Throttling, and Rate Limit policies, respectively. These policies must execute before others. The following example shows how to set the order property in the <policy> tag:

<?xml version="1.0" encoding="UTF-8"?>
<policy id="7777"
        policyName="A"
        order="3"
        xmlns="http://www.mulesoft.org/schema/mule/policy"
        xmlns:mule="http://www.mulesoft.org/schema/mule/core"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:api-platform-gw="http://www.mulesoft.org/schema/mule/api-platform-gw"
        xsi:schemaLocation="http://www.mulesoft.org/schema/mule/policy http://www.mulesoft.org/schema/mule/policy/current/mule-policy.xsd
              http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
              http://www.mulesoft.org/schema/mule/api-platform-gw http://www.mulesoft.org/schema/mule/api-platform-gw/current/mule-api-platform-gw.xsd">

    <before>
         <mule:logger level="INFO" message="POLICY A" />
    </before>

    <pointcut>
        <api-platform-gw:api-pointcut apiName="Leagues API" apiVersion="1.0.0"/>
    </pointcut>
</policy>

Order Property in Before or After Tags

Alternatively, you can set the order of execution of policies in the <before></before>and <after></after> tags. Setting the order `property in the `before and after tags takes precedence over any order setting in the policy tag. Set order to an integer greater than 2. For example:

<?xml version="1.0" encoding="UTF-8"?>
<policy id="2"
       ...

    <before order="4">
       <mule:set-payload value=" before cust2 "/>
       <mule:logger level="INFO" message="#[payload]" />
    </before>

    <before order="3">
       <mule:set-payload value=" before cust2.1 "/>
       <mule:logger level="INFO" message="#[payload]" />
    </before>

requiresContracts in Policy Tag

The following versions support a requiresContracts property in the policy tag of the configuration XML:

  • The Mule Gateway Runtime 2.2.0 or later

  • Mule Runtime 3.8 or later

In earlier versions, you do not need this property because Mule Gateway Runtime caches client credentials by default.

Important: Enabling the requiresContracts property is vital for client validation. In the event Anypoint Platform goes down, a policy can continue to validate clients. Validation checks occur in-memory, which is naturally more performant than checks that involve an HTTP request over a network.

Custom policies that validate client IDs are often variations of MuleSoft-provided policies that authenticate clients, such as Client ID Enforcement or SLA-based policies.

In a custom policy that validates client IDs, include requiresContracts and set this boolean property to true as shown in the following example snippet.

<?xml version="1.0" encoding="UTF-8"?>
<policy id="{{policyId}}"
        policyName="Custom Client Id Enforcement"
        online="true"
        requiresContracts="true"
        xmlns="http://www.mulesoft.org/schema/mule/policy"/>
...

API client identity and authentication credentials are downloaded to Mule Gateway Runtime or Mule Runtime and stored. Validation occurs within the Runtime, eliminating the need for an outbound HTTP Request to do the validation.

Downloading and retrieving client information takes place in the background and occurs every 15 seconds by default. You can configure the polling frequency using the anypoint.platform.poll_clients_freq property. Configure this property on the CloubHub properties tab or the wrapper.conf file in your <MULE_HOME>/conf folder.

Policy Definition YAML File

The policy definition file defines the high level properties of the policy, the configurable parameters, labels, and tips that are visible as a UI when implementing the policy.

The following example shows the IP Allowlist policy definition YAML file:

id: ip-whitelist
name: IP Allowlist
description: Limits all service calls to a defined set of IP addresses.
category: Security
standalone: true
requiresConnectivity: false
resourceLevelSupported: true
providedCharacteristics:
  - IP filtered
requiredCharacteristics: []
configuration:
  - propertyName: ipExpression
    name: IP expression
    description: |
      Mule Expression for extracting the IP address from this API request.
      for example, #[message.inboundProperties['http.headers']['X-Forwarded-For']]
    type: expression
    defaultValue:
    optional: true
    sensitive: false
    allowMultiple: false
  - propertyName: ips
    name: Allowlist
    description: Limited list of IP addresses allowed API access
    type: ipaddress
    optional: false
    sensitive: false
    allowMultiple: true

New properties you define have values based on what you want users to configure when they apply a policy. The IP Allowlist policy example requires values for the ipExpression and ips properties. The Policy Configuration XML file references these properties. Users are prompted to assign values to them.

The following policy definition values are related to the new policy:

Parameter Description

name

string - Policy name

description

string - A description that displays in the policy details when applying it

category

string - Category of the policy

standalone

boolean - True if the policy can work on its own or false if the policy can be applied only as part of another policy.

providedCharacteristics

array - A list of optional characteristics that are fulfilled by applying this policy.

requiresConnectivity

boolean - A legacy internal parameter. The functionality is not implemented.

resourceLevelSupported

boolean - True means the user can apply the policy to specific API resources; False means the policy applies to all API resources. (Mule 3.8.1 and later)

requiredCharacteristics

array - A list of required characteristics that are fulfilled before this policy can be applied. Required characteristics can be fulfilled by applying other policies that provide these. This allows dependencies between policies. Any string input is valid as a characteristic name as long as at least one other policy provides this characteristic, these are case sensitive.

configuration

array - A set of configurable properties associated with your policy, details on the parameters for each property below.

ramlSnippet

string - A security scheme described in the RAML 0.08 specification.

ramlV1Snippet

string - A security scheme described in the RAML 1.0 specification.

providedCharacterics Parameter

Typically, you set providedCharacteristics to avoid clashes between policies that cannot be applied at the same time. For example, only one OAuth 2.0 policy can be applied at a time. Use the OAuth 2.0 protected to specify only one OAuth 2.0 policy.

The list of existing characteristics is:

  • Client ID required

  • CORS enabled

  • Baseline Rate Limiting

  • SLA Rate Limiting

  • Requires authentication

  • IP filtered

  • JSON threat protected

  • Security manager

  • OAuth 2.0 protected

  • OAuth 2.0 provider

  • XML threat protected

This list is unlimited: any string input is valid as a characteristic name. The list items are case sensitive.

configuration Parameter

The configuration parameter lists a set of properties. Each can contain the following parameters:

Parameter Description

propertyName

string - Property name for internal reference.

name

string - Property name to display in configuration window.

description

string - Property description to display in configuration window.

type

string - Data type: string, boolean, int, ipaddress, expression (in MEL), keyvalues, rateLimits. If type = int, define minimumValue and maximumValue.

optional

boolean - True if assigning a value for it is optional.

sensitive

boolean - True if the information contained by this field is sensitive (typically used for passwords and tokens). When policy information is requested from the server, these sensitive fields are filtered out.

allowMultiple

boolean - True if multiple values can be assigned.

minimumValue

int - Only for values of type int and required.

maximumValue

int - Only for values of type int and required.

defaultValue

Only for properties of type int, boolean, string and expression.

propertyName Syntax

The following snippets show how to define propertyName parameters of the following types:

  • Integer

  • Boolean

  • String

  • Map

Integer

If type = int, you must define minimumValue and maximumValue.

configuration:
 - propertyName: aint
   name: Test Int single between 5 and 10
   description: Some Description
   type: int
   minimumValue: 5
   maximumValue: 10
   optional: true
   sensitive: false
   allowMultiple: false

Boolean

configuration:
 - propertyName: aboolean
   name: Test Boolean single
   description: Some Description
   type: boolean
   optional: true
   sensitive: false
   allowMultiple: false
   defaultValue: false

String

configuration:
 - propertyName: astring
   name: Test String single
   description: Some Description
   type: string
   optional: true
   sensitive: false
   allowMultiple: false

Map

configuration:
 - propertyName: amap
   name: Test Key/Value Map
   description: Some Description
   type: keyvalues
   optional: true
   sensitive: false
   allowMultiple: true

ramlSnippet and ramlV1Snippet Parameters

In the YAML of the custom policy, you can include the ramlSnippet and ramlV1Snippet parameters. When you add the custom policy to Anypoint Platform, links for the RAML .80 or RAML 1 snippets show up in the Applied Policies list.

The following snippet shows ramlSnippet and ramlV1Snippet parameters in a snippet of the YAML file of the MuleSoft-provided, Throttling-SLA based policy:

id: test
name: test
description: Rosario Central
...
configuration:
  - propertyName: omar
    name: arnaldo
...
  - propertyName: rosario
    name: central
...
ramlSnippet: |
  traits:
  - client-id-required:
      queryParameters:
        client_id:
          type: string
        client_secret:
          type: string
  ...
  /products:
  get:
    is: [client-id-required]
    description: Gets a list of all the inventory products.
ramlV1Snippet: |
  traits:
  client-id-required:
    queryParameters:
      client_id:
        type: string
      client_secret:
        type: string
  ...
  /products:
  get:
    is: [client-id-required]
    description: Gets a list of all the inventory products.

See Also