function main(Data)
   -- Set up the parameters to be used with sending an email
   local smtpparams={
      header = {To = 'sales@interfaceware.com'; 
                From = 'testuser@mailserver.com'; 
                Date = 'Thu, 23 Aug 2001 21:27:04 -0400';
                Subject = 'Test Subject';},
      username = 'user',
      password = 'password',
      server = 'smtp://domain.mailserver.com:25',
      -- note that the "to" param is actually what is used to send the email, 
      -- the entries in header are only used for display. 
      -- For instance, to do Bcc, add the address in the  'to' parameter but 
      -- omit it from the header.
      to = {'sales@interfaceware.com','admin@interfaceware.com'},
      from = 'Test User <testuser@mailserver.com>',
      body = 'This is the test body of the email',
      use_ssl = 'try'
   } 

  net.smtp.send(smtpparams)
end

One of the great things about the Translator is how easy it is to extend the functionality of Iguana. This is an example of writing a module in Iguana to monitor the queue count for a channel. This shows the usage of a queuemon module to check that the count of messages on a queue has not exceeded the given threshold.

If the queue count exceeds the threshold the script will log “ALERT:” followed by a description of the problem. That makes it very easy to detect this condition using a standard notification rule.

There are two examples given of calling this function. If no arguments are given then the script defaults to the current channel name and will raise an alert if the channel count exceeds 100.

These defaults can be overridden which is what the second example shows:

Source Code

You can load the code into the Translator from this project zip file MonitorQueueSize-FromTranslator, or copy and paste from below.

main module:

require 'queuemon'

function main()
   -- Using default parameters
   queuemon.checkQueue()

   -- Setting the channel name and count explicitly
   queuemon.checkQueue{channel = '<your channel name>', count = 10000}   
end

queuemon module:

require 'iguanaconfig'

queuemon = {}

local function CheckChannel(Chan, Count, Name)
   if Chan.Name:nodeValue() == Name then
      local QC = tonumber(Chan.MessagesQueued:nodeValue())
      if QC > Count then
         iguana.logDebug('ALERT:\n Channel '..Name..' has '..QC..' messages queued.') 
         return true
      end   
   end
end

function queuemon.checkQueue(Param)
   -- We default to a queue count of 100
   if not Param then Param = {} end
   if not Param.count then Param.count = 100 end
   if not Param.channel then Param.channel= iguana.channelName() end

   local url = ''
   local webConfig = iguanaconfig.config().iguana_config.web_config
   -- use http or https for API query based on Iguana settings
   if webConfig.use_https:S() == 'true' then
      url = 'https://localhost:'
   else
      url = 'http://localhost:'    
   end
   url = url ..
   webConfig.port..'/status.html'
   iguana.logDebug(tostring(url))
   trace(url)

   -- We need a user login here - using *admin* for demo only  (as it usually works)
   -- Best to use a user with minimal permissions.
   local S = net.http.get{url=url, 
      parameters={UserName='admin',Password='password', Format='xml'}, 
      live=true}
   trace(S)
   S = xml.parse{data=S}

   for i = 1, S.IguanaStatus:childCount('Channel') do
      local Chan = S.IguanaStatus:child("Channel", i)
      local QC = CheckChannel(Chan, Param.count, Param.channel)
      if QC then return QC end
   end
   return
end

iguanaconfig module (used by the queuemon module):

-- This module does a lazy load of the Iguana Configuration file - it only loads the file once
iguanaconfig={}

-- relative path (from working directory) to the config file
-- you can substitute with the *absolute* path if you have problems
local CONFIG_FILE = 'IguanaConfigurationRepo/IguanaConfiguration.xml'

-- We open the configuration file once at compile time
local F = io.open(CONFIG_FILE, 'r')
local C = F:read('*a')
F:close() -- best practice to close (open filehandle can prevent Iguana updating config file on Win machines)

function iguanaconfig.config(A)
   return xml.parse{data=C}
end

The iguanaconfig module just loads the IguanaConfiguration.xml file and returns it as a XML document. It’s extremely useful for all sorts of things.

In this case we use it to pull back the port number that the Iguana instance is listening on.

This module uses the web monitoring URL to pull back the XML summary and parses it to find the queue counts for the channel. In this case we are only selecting one channel to check the queue count but there is no reason we could not check all the channels or even parse a group of channels and only check the queue counts on that channel group.

If you would like to see this script extended in that manner please contact support at support@interfaceware.com.