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 Client 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.

• The DiameterLuaAgent is tied to the diameter action key.
• The DIAMETER-C-SENT message is written to the debug trace log, but not available to the Lua script.

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"/>
          </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.

Invoking DiameterLuaAgent

A Lua Script can access the DiameterLuaAgent diameter action with code such as the following:

    local n2svcd = require "n2.n2svcd"
    local diameter_client_api = require "n2.n2svcd.diameter_client"

    local handler = function (soap_args)

        local result = diameter_client_api.request ('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
    end

    return n2svcd.handler (handler)

This is standard Lua-style library usage. The n2/n2svcd/diameter_client.lua library is loaded with require "n2.n2svcd.diameter_client". Then methods are invoked on the returned library object.

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

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

The request method accepts an request object parameter with the following attributes.

The request method returns a Diameter response object with the following attributes.

Note that the decoded .avps array will contains 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.

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.