Diameter Lua Agent

Introduction

The DiameterLuaAgent is an asynchronous helper for Lua scripts running within the LogicApp. It is used for sending out Diameter client requests.

• The Diameter Agent may be used by any Lua script, regardless of which Service initiated that script.

The DiameterLuaAgent communicates with one or more instances of the DiameterApp which can be used to communicate with one or more external Diameter servers.

The DiameterLuaAgent communicates with the DiameterApp using the DIAMETER-C-… messages.

Diameter Agent API methods are accessed via the “n2.n2svcd.diameter_agent” module:

local diameter_api = require "n2.n2svcd.diameter_agent"

Configuring DiameterLuaAgent

The DiameterLuaAgent is configured within a LogicApp.

    <?xml version="1.0" encoding="utf-8"?>
    <n2svcd>
      ...
      <applications>
        ...
        <application name="Logic" module="LogicApp">
          <include>
            <lib>../apps/logic/lib</lib>
          </include>
          <parameters>
            ...
            <parameter name="default_diameter_app_name" value="DIAMETER-CLIENT"/>
            <parameter name="diameter_app_name_sms" value="DIAMETER-CLIENT-SMS"/>
          </parameters>
          <config>
            <services>
              ...
            </services>
            <agents>
              <agent module="DiameterApp::DiameterLuaAgent" libs="../apps/diameter/lib"/>
            </agents>
          </config>
        </application>
        ...
      </application>
      ...
    </n2svcd>

Under normal installation, following agent attributes apply:

In addition, the DiameterLuaAgent must be configured with the name of the DiameterApp with which it will communicate. This is configured within the parameters of the containing LogicApp.

The DiameterLuaAgent API

All methods may raise a Lua Error in the case of exception, including:

• Invalid input parameters supplied by Lua script.
• Unexpected results structure returned from DiameterApp.
• Processing error occurred at DiameterApp.
• Timeout occurred at DiameterApp.

.request_response [Asynchronous]

The request_response method sends a Diameter request, and returns the response. The following parameters are accepted.

The request_response method returns a Diameter response object with the following fields.

Example (Diameter Client Request):

local n2svcd = require "n2.n2svcd"
local diameter_api = require "n2.n2svcd.diameter_agent"

local soap_args = ...

local result = diameter_api.request_response ('sms', 'Credit-Control-Request', {
    { name = "Service-Context-Id", value = "sms@huawei.com" },
    { name = "CC-Request-Type", value = 1 },
    { name = "CC-Request-Number", value = 1 },
    { name = "Rating-Group", value = 900 },
    { name = "Requested-Action", value = 0 },
    { name = "Requested-Service-Unit",
        value = { { name = "CC-Service-Specific-Units", value = 1 } },
        vendor_specific = 0
    },
    { name = "Service-Identifier", value = 200 },
    { name = "Subscription-Id",
        value = {
            { name = "Subscription-Id-Data", value = "64220635462" },
            { name = "Subscription-Id-Type", value = 0 }
        }
    },
    { name = "Custom-1", value = 789 }
}, true)

soap_response = {}
soap_response['status'] = 'ok'

return soap_response

The above example shows a LogicApp script invoked by a SoapLuaService.

Note that the decoded .avps array will contain all fields, i.e. the [].name and [].code and [].type and [].mandatory, etc. will all be present.

The only exception will be when decoding AVPs which are not part of the core fields defined within N2::DIAMETER::Codec and are not defined as custom AVPs in the configuration for DiameterApp. In these cases, the [].name and [].type AVP attributes will not be present, and the [].value will be the raw undecoded bytes of the AVP value without any interpretation.

.get_first_instance_of_avp [Synchronous]

The get_first_instance_of_avp method searches an array of AVPs, returning the first AVP with name matching a specified name. The following parameters are accepted.

If a matching AVP is found, the get_first_instance_of_avp method returns an avp object with the following fields.

.get_first_value_of_avp [Synchronous]

The get_first_value_of_avp method searches an array of AVPs, returning the value of the first AVP with name matching a specified name. The following parameters are accepted.

If a matching AVP is found, the get_first_value_of_avp method returns that AVP’s value. For AVPs of type Grouped this will be an ARRAY of AVPs. For all other AVPs this is a SCALAR of the appropriate type.

.get_all_instances_of_avp [Synchronous]

The get_all_instances_of_avp method searches an array of AVPs, returning all AVPs with name matching a specified name. The following parameters are accepted.

If at least one matching AVP is found, the get_all_instances_of_avp method returns an array of AVPs as per get_first_instance_of_avp. Otherwise an empty array is returned.

Built-In N2::Diameter::Codec Commands

The following list of Command names is built-in to the N2::Diameter::Codec encoding and decoding library. Commands not in this list may be referenced by numeric code, although they will not have support for setting special flags, or for changing the Diameter Application ID.

Built-In N2::Diameter::Codec AVPs

The following list of AVPs is built-in to the N2::Diameter::Codec encoding and decoding library. Additional custom AVPs may be added as necessary on a per-site basis by using configuration in the DiameterApp.