Archive for August, 2011

Employing Scrum

August 29, 2011

In this post, it’s my intention to bring some clarity to the following question.

Why does a business decide to employ Scrum as the chosen framework that their development team/s use for managing the business’s projects / work items?


A team that sets out to run by the Scrum framework, should

  • Do so with the intention that Scrum is just a path way to building a more efficient team.
  • Expect that in a years time, the process’s they are using,
    should be different to those that they started using when they first started working with Scrum.

What I mean by this is, textbook Scrum is a great starting point,
but you shouldn’t expect to be doing things the same way in say, a years time.

Teams enter the scrum playing field with the Kaizen philosophy of aiming for continual improvement.
Not just in terms of product output, but also on a personal level.
Who wants to buy into a methodology that only provides benefit to the business they work for?

The team should

  • Learn it’s strengths and weaknesses.
  • Celebrate and acknowledge success.
  • Continually improve on areas that require improvement.

Scrum is designed to facilitate these principles.

Many of the Scrum procedures focus on the five foundational elements of Kaizen.

  1. Teamwork
  2. Personal discipline
  3. Improved morale
  4. Quality circles
  5. Suggestions for improvement

Out of the above elements
The following three key factors arise.

  1. Elimination of waste and inefficiency.
  2. The Kaizen five-S framework for good housekeeping.
    1. tidiness
    2. orderliness
    3. cleanliness
    4. standardized clean-up
    5. discipline
  3. Standardization.


User Story

An item of work to be completed in a Sprint.
Often a good idea to aim at creating User Stories that can be completed within a week by one or two members.
Some written by the team often with the help of Stakeholders, Product Owner.
Some written by a developer which formulates the User Story based on understanding of the Stakeholders requirements.
Written from the perspective of the end user,
or who will get the benefit of the completed work item.
The three components of the User Story are,
Actor, Action, Achievement, as in the following form.
As an <Actor> I want to <Action> so that <Achievement>

For example

As the User of the new system, I want to be able to submit a new support ticket,
so that I can record the clients concern in sufficient detail.


Tasks are created in the Sprint Planning meeting,
once the User Stories have been pulled onto the Task Board.
Each User Story is broken down into tasks by the team, and then given a time estimate.
Each task shouldn’t take more than a day for one person, preferably no more than 5 hours.
Both functional and non-functional requirements should be considered.
A typical set of tasks may include the following

  • Test Conditions (or just a design session for the story)
  • Test Suite
  • Unit Tests
  • A set of development tasks
  • Acceptance Tests
  • Integration Tests
  • Code Review
  • Documentation (wiki, barely sufficient)
  • End user documentation

Release Burn down Chart

On large projects,
where most/all of the User Stories have been defined prior to start of Sprints,
a manager can also maintain a Release Burn down.
This shows the amount of work left before product release.
The Release Burn down usually covers multiple / many iterations (sprints).

Sprint Burn down Chart

Shows quantitatively, the remaining work left on the Sprint Backlog.
This is updated after each daily Standup.

Product Backlog

The collection of User Stories waiting to be pulled into a Sprint.
Created before Sprints start, and maintained while Sprints are running.
Each user story is given a Story Point value, based on gut feel of how much work is involved in the User Story.

Sprint Backlog

The User Stories that have been pulled onto the Task Board by the Scrum Master, at the Product Owners request, at Sprint Planning.
The Sprint Backlog is owned by the team.
Workers pull tasks from Todo column into In Progress through to Complete.
Each worker aiming to have as few tasks In Progress at any one time.

Definition of Done

This is a team statement that defines what it means for every User Story to be completed.
If a User Story is done,
it forms part of the Potentially Shippable product that each sprint must deliver.
A list of done criteria.
An example could be

  •         Code Complete
  •         Unit tests written and executed
  •         Integration tested
  •         Performance tested
  •         Documented (just enough)



Those that have a direct interest in the project (customers, vendors)
Directly affected by the projects outcome.
Only directly involved in the process during the Sprint Review meetings

Product Owner

Represents the Stakeholders, and what they want.
Is accountable for ensuring that the team delivers value to the business.
Often a member of the development team,
but shouldn’t be combined with the role of Scrum Master.


Responsible for setting up the team,
scheduling and actioning Scrum Master concerns (team blockers).

Scrum Master

It’s the Scrum Masters responsibility to make sure the team delivers what it signed up to deliver.
Acts as a buffer between the rest of the team members and any distracting influences.
Remove impediments, and liaises with Manager.
Enforces rules,
and keeps team members working to Scrum guidelines
Keeps team focused on task board and what they have to deliver.
Facilitator, Servant Leader.


The body of individuals that form a multi functional unit,
responsible for delivering the Potentially shippable body of work defined by the Sprint Backlog each Sprint.
Typically made up of 7 plus or minus 2 cross-functional workers.
Roles included: BA’s, Testers, Technical Writers, Engineers.
The Scrum Team in Scrum terminology are known as ‘Pigs’,
whilst everyone else are known as ‘Chickens‘.
See Pigs and Chickens for the story.


Sprint Planning

First section

Product Owner and Team communicate and decide on which User Stories from the Product Backlog will be pulled into the Sprint Backlog.
Often Planning Poker is used to make sure the Team still agrees with the Story Point values attached to each User Story.

Second section

Attended by the Team, which defines the Tasks and attach time values to them.
Time values are then added up to create the total expected hours for the Sprint.
The Team,
then records all the hours available from all of the Team members minus contingency time.
If the total expected hours are greater than the available hours,
the Team lias and decide whether or not to pull a User Story from the Sprint Backlog back to the Product Backlog.
The Product Owner will then be consulted on which User Story to remove.


Usually time boxed to 15 minutes.
Performed every morning, same place, same time.
Everyone is welcome,
but only Team, Scrum Master and Product owner are usually allowed to speak.
Make sure the Task Board is updated prior to meeting commencing.
While talking to the Task Board, each Team member specifies the following

  • What they have done since last Standup
  • What they intend to do today
  • What they see as blockers, or hindering them in achieving goals

Scrum Master address’s any blockers and provides direction to alleviate.
Larger organisations have a Standup of Standups to discuss overlapping concerns.

Sprint Review

Held on the last day of the Sprint.
Review work that was completed and not completed.
Delegate completed sections of work to Team members to demo to Stakeholders.

Show And Tell

Each member demo’s the work they were assigned to demo to the Stakeholders.
This provides insight into how the team is progressing.
Assists with buy-in.
There should be no surprises here,
because the Stakeholders were included in creating User Stories,
and the Product Owner has worked closely with them.

Sprint Retrospective

Reflect on finished sprint.
What went well, what didn’t go so well.
How we can improve the process.
Produce action plans for points raised and assign to a Team member to facilitate for the next Sprint.
Between 30 to 60 minutes in duration.


Planning Poker

Applies Story Points to the User Stories.
Each team member holds a card up with a number,
representing how much work they think is involved in completing the User Story.
The DoD must be defined,
and often the member knowing the most about the User Story will provide a brief detailed explanation of what they think is involved.
Often performed when initial Product Backlog is created, and also as part of the Sprint Planning meeting.
This aids the Product Owner in prioritisation and planning ahead.


A set length period of time in a series,
in which a collection of User Stories,
that the team has committed themselves to completing are embarked upon.
This period of time usually ranges from one week to four weeks and is performed consecutively.
A successful Sprint is defined by having all of it’s User Stories complete according to the DoD.


Text book Scrum, has for many business’s, what often seem like wasteful procedures.
Often what you find, once you’ve started with Scrum,
is that quite a few of these procedures are in fact very helpful,
and provide real benefits to both business and all those involved in the framework.

Teams enter the Scrum playing field with the express intention of improvement.
We have the luxury of learning from other teams mistakes and improvements,
as Scrum is not a new idea.
As Agile methodologies are fairly well defined,
and offer considerable flexibility to allow and promote change,
in the environments they are employed in.

Function Declarations vs Function Expressions

August 17, 2011

This short post is in reaction to this post
on JavaScript Function Declarations and Function Expressions.
My concern was with the littering of the global object.

Subject to hoisting

  • function statements or function declarations
  • variable declarations, but not their assignment expressions

Function Statement
sometimes just a pseudonym for a Function Declaration
in Mozilla a Function Statement is an extension of Function Declaration
allowing the Function Declaration syntax to be used anywhere a statement
——is allowed.

Don’t forget; when a function is not the property of an object, it’s invoked as a function.
The this of the function is bound to the global object.
∴ foo and also bar are bound to the global object.
This is not good.
As Douglas Crockford puts it (and rightfully so), we’re clobbering the global variables.
I think a better way to do this, would be like the following code examples.

A few words on access first

All members of an object are public
You can add public members in the constructor, by using the
this keyword (which by the way, provides “privileged” access).
If you want to add private members, you can use a constructor Function.
You are actually adding the member to the function.
Private members are only accessible via the objects privileged members.
Privileged members are able to access private members,
and are themselves accessible to public members and outside.

Have a look at Angus Croll’s post to provide some context.

Question 1

function Foo(){
   function bar() {      //private
      return 3;
   this.barMeth = bar(); //privileged
   function bar() {      //private
      return 8;
var myFoo = new Foo();

Question 2

function Foo(){
   var bar = function bar() { //private
      return 3;
   this.barMeth = bar();      //privileged
   var bar = function bar() { //private
      return 8;
var myFoo = new Foo();

Question 3

var myFoo = new Foo();
function Foo(){
   var bar = function bar() { //private
      return 3;
   this.barMeth = bar();      //privileged
   var bar = function bar() { //private
      return 8;

Question 4

function Foo(){
   this.barMeth = bar();          //privileged
   var bar = function bar() {     //private
      return 3;
   var barMeth = function bar() { //private
      return 8;
var myFoo = new Foo();

Or worse, but still not clobbering the global object…

var myApp = {};

myApp.fooTest = {
   foo: function (){
      function foo(){
         function bar() {
            return 3;
         return bar();
         function bar() {
            return 8;

Quick walk through, of my UPS library

August 4, 2011

Part three of a three part series

On setting up a UPS solution, to enable clean shutdown of vital network components.

In this post, we’ll be reviewing the library that performs the shutting down of our servers.

When I started on the library PowerOffUPSGuests.dll,
my thoughts were, if I’m going to do this, I wanted it to be extensible.
Able to shutdown pretty much any machines, requiring a clean shutdown due to power failure.
What I’ve done is left points to be easily extended in the future, when new requirements present themselves.

Source Code

The PowerOffUPSGuests repository is on bitbucket

I’m assuming you know how to use Mercurial and have it installed on your dev machine.
If you’re not familiar with Mercurial (hg) There’s a little here to get your feet wet.
Besides that, there is plenty of very good documentation on the net.
For starters, you’ll need to create a directory that you want to have as your repository.
For example, I use C:\Scripts.
Set this directory as a repository.
Then from within the directory,
issue an hg pull
Then update your working directory to the tip of the local repository.

You’ll need a BinaryMist.PowerOffUPSGuests.dll.config in your <repository>\UPS\PowerOffUPSGuests\PowerOffUPSGuests\
which should look something like the following.
At this stage I’ve only been shutting down an ESXi host.
Replace the value at line 22 with the user that has privileges to perform shutdown on the server.
Replace the value at line 23 with the absolute path to the password file you’re about to generate.
Line 28 is the class name of the ServerController.
Line 34 denotes whether or not the Initiator will perform the shutdowns synchronously or asynchronously
The Server[n] and ServerPort[n] values that are commented out, are used when you want to intercept the messages being sent to/from the target server.
This is useful for examination and to help build the appropriate messages that the target server expects.

<?xml version="1.0"?>
      <!--As aditional target servers are added to the queue to be shutdown
         Keep the same nameing convention used below
         Just increment the suffix number for each target servers key.
         The first target suffix must start at 0.
         Additional target suffix's must be sequential.

      <!--Target servers to be shutdown-->

      <!--add key="ServerUser0" value="YourUser"/>
      <add key="ServerUserPwFile0" value="Absolute directory that your password file resides\FileServerPw"/-->
      <!--add key="Server0" value=""/--><!--localhost used for interception-->
      <!--add key="Server0" value="YourFileServerName"/-->
      <!--add key="ServerPort0" value="8080"/--><!--port used for interception-->
      <!--add key="ServerPort0" value="443"/-->
      <!--add key="Controller0" value="FreeNASController"/-->

      <add key="ServerUser0" value="YourUser"/>
      <add key="ServerUserPwFile0" value="Absolute directory that your password file resides\VMHostPw"/>
      <!--add key="Server1" value=""/--><!--localhost used for interception-->
      <add key="Server0" value="YourVSphereHostName"/>
      <!--add key="ServerPort1" value="8080"/--><!--port used for interception-->
      <add key="ServerPort0" value="443"/>
      <add key="Controller0" value="VMServerController"/>

      <!--Assembly settings-->

      <add key="LogFilePath" value="Some absolute path\Log.txt"/>
      <add key="CredentialEntropy" value="A set of comma seperated digits"/><!--"4,2,7,9,1" for example-->
      <add key="Synchronicity" value="Synchronous"/> <!--Check other values in Initiator.Synchronicity-->
      <add key="IgnoreSslErrors" value="true"/>
      <add key="Debug" value="true"/>

<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup></configuration>

Build the solution

You’ll now need to navigate to <repository>\UPS\PowerOffUPSGuests\
and run the file PowerOffUPSGuests.sln.
You should now notice a couple of binaries in <repository>\UPS\
along with the libraries config file.
As I mentioned in part two, the PCNS will execute <repository>\UPS\PowerOff.bat which will run PowerOffUPSGuests.ps1.
Which will inturn kick off the BinaryMist.PowerOffUPSGuests.dll which does the work.

Generate the encrypted password file

Just run the BinaryMist.PasswordFileCreator.exe.
This will provide the required user prompts to capture the password for the vSphere host you’re intending to shutdown.
Or if you would like to extend the project and create a specialized ServerController for your needs.
You can use the BinaryMist.PasswordFileCreator to capture any credentials and save to file.

The code that performs the capture and encryption looks like the following:

        static void Main() {

        /// <summary>
        /// Provides interactive capture for the insertion of an encrypted password,
        /// based on the ServerUserPwFile0 specified in the BinaryMist.PowerOffUPSGuests.dll.config file.
        /// </summary>
        public static void CreatePasswordFile() {

            bool validPath;
            string path = null;
            string RetryMessage = "Please try again.";

            Console.WriteLine("You must create the password file running under" + Initiator.NewLine + "the same account that will run BinaryMist.PowerOffUPSGuests.");

            do {
                    "From the BinaryMist.PowerOffUPSGuests.dll.config file." + Initiator.NewLine +
                    "Please specify the ServerUserPwFile[n] value" + Initiator.NewLine +
                    "for the encrypted Password to be stored to." + Initiator.NewLine +
                    "This must be a valid path" + Initiator.NewLine

                try {
                    validPath = true;
                    path = Path.GetFullPath(Console.ReadLine());

                    if (!
                            path, StringComparer.CurrentCultureIgnoreCase
                    ) {
                        Console.WriteLine("The value that was entered" + Initiator.NewLine +
                            "was not one of the specified values for ServerUserPwFile[n]");
                        Console.WriteLine(RetryMessage + Initiator.NewLine);
                        validPath = false;
                } catch (Exception) {
                    Console.WriteLine(Initiator.NewLine + "An invalid path was entered." + Initiator.NewLine + RetryMessage + Initiator.NewLine);
                    validPath = false;
            } while (validPath == false);

                + "The password you are about to enter"
                + Initiator.NewLine
                + "will be encrypted to file \"{0}\""
                , path

            byte[] encryptedBytes = ProtectedData.Protect(
                new ASCIIEncoding().GetBytes(pWord),
            File.WriteAllBytes(path, encryptedBytes);

                + Initiator.NewLine
                + string.Format(
                    "The password you just entered has been encrypted"
                    + Initiator.NewLine
                    + "and saved to {0}"
                    , path
            Console.WriteLine(Initiator.NewLine + "Press any key to exit");


        private static string pWord {
            get {
                bool passWordsMatch = false;
                bool firstAttempt = true;
                string passWord = null;
                while (!passWordsMatch) {

                    if (!firstAttempt)
                        Console.WriteLine(Initiator.NewLine + "The passwords did not match." + Initiator.NewLine);

                    Console.WriteLine(Initiator.NewLine + "Please enter the password..." + Initiator.NewLine);
                    string passWordFirstAttempt = GetPWordFromUser();
                    Console.WriteLine(Initiator.NewLine + Initiator.NewLine + "Please confirm by entering the password once again..." + Initiator.NewLine);
                    string passWordSecondAttempt = GetPWordFromUser();

                    if (string.Compare(passWordFirstAttempt, passWordSecondAttempt) == 0) {
                        passWordsMatch = true;
                        passWord = passWordFirstAttempt;
                    firstAttempt = false;
                Console.WriteLine(Initiator.NewLine + Initiator.NewLine + "Success, the passwords match." + Initiator.NewLine);
                return passWord;


        private static string GetPWordFromUser() {
            string passWord = string.Empty;
            ConsoleKeyInfo info = Console.ReadKey(true);
            while (info.Key != ConsoleKey.Enter) {
                if (info.Key != ConsoleKey.Backspace) {
                    if (info.KeyChar < 0x20 || info.KeyChar > 0x7E) {
                        info = Console.ReadKey(true);
                    passWord += info.KeyChar;
                    info = Console.ReadKey(true);
                } else if (info.Key == ConsoleKey.Backspace) {
                    if (!string.IsNullOrEmpty(passWord)) {
                        passWord = passWord.Substring
                            (0, passWord.Length - 1);
                        Console.SetCursorPosition(Console.CursorLeft - 1, Console.CursorTop);
                        Console.Write(' ');
                        Console.SetCursorPosition(Console.CursorLeft - 1, Console.CursorTop);
                    info = Console.ReadKey(true);
            return passWord;

Once you’ve created the password file, you’re pretty much ready to start testing.
If you’ve followed the directions covered in the first two parts of this series, you should be good to go.
Part one.
Part two.

We’ll quickly go through some of the more interesting parts of the code…

The ConfigReader

The constructor loads the _settings IDictionary by calling the ReadConfig function.
.net libraries don’t usually contain an assembly config file.
This is how we get around it.
We read the name of the assemblies config file (see line 70).
We then load the configuration into an XmlDocument.
Create and populate the XmlNodeList.
Return the populated IDictionary.

    /// <summary>
    /// Reads the libraries configuration into memory.
    /// Provides convienient readonly access of the configuration from a single instance.
    /// </summary>
    public class ConfigReader {

        #region singleton initialization
        private static readonly Lazy<ConfigReader> _instance = new Lazy<ConfigReader>(() => new ConfigReader());

        /// <summary>
        /// constructor that sets the value of our "_settings" variable
        /// </summary>
        private ConfigReader() {
            _settings = ReadConfig(Assembly.GetCallingAssembly());

        /// <summary>
        /// The first time Read is called must be from within this assembly,
        /// in order to create the instance of this class for the containing assembly.
        /// </summary>
        public static ConfigReader Read {
            get {
                return _instance.Value;

        /// <summary>
        /// settings to be used throughout the class
        /// </summary>
        private IDictionary _settings;
        /// <summary>
        /// constant name for the node name we're looking for
        /// </summary>
        private const string NodeName = "assemblySettings";

        /// <summary>
        /// class Indexer.
        /// Provides the value of the specified key in the config file.
        /// If the key doesn't exist, an empty string is returned.
        /// </summary>
        public string this[string key] {
            get {
                string settingValue = null;

                if (_settings != null) {
                    settingValue = _settings[key] as string;

                return settingValue ?? string.Empty;

        public IDictionary<string, string> AllKeyVals {
            get {
                IDictionary<string, string> settings = new Dictionary<string, string>();
                foreach(DictionaryEntry item in _settings) {
                    settings.Add((string)item.Key, (string)item.Value);
                return settings;

        /// <summary>
        /// Open and parse the config file for the provided assembly
        /// </summary>
        /// <param name="assembly">The assembly that has a config file.</param>
        /// <returns></returns>
        private static IDictionary ReadConfig(Assembly assembly) {
            try {
                string cfgFile = assembly.CodeBase + ".config";

                XmlDocument doc = new XmlDocument();
                doc.Load(new XmlTextReader(cfgFile));
                XmlNodeList nodes = doc.GetElementsByTagName(NodeName);

                foreach (XmlNode node in nodes) {
                    if (node.LocalName == NodeName) {
                        DictionarySectionHandler handler = new DictionarySectionHandler();
                        return (IDictionary)handler.Create(null, null, node);
            } catch (Exception e) {

            return (null);

        #region Config related settings

        /// <summary>
        /// Readonly value, specifying whether debug is set to true in the assemblySettings of the BinaryMist.PowerOffUPSGuests.dll.config file.
        /// </summary>
        public bool Debug {
            get {
                if (_debug != null)
                    return _debug == true ? true : false;
                _debug = Read["Debug"] == "true" ? true : false;
                return _debug == true ? true : false;
        private bool? _debug;



The Initiator

private void ShutdownSynchronously(Queue<ServerController> serverControllers) {
    foreach (ServerController serverController in serverControllers) {

private void ShutdownAsynchronously(Queue<ServerController> serverControllers) {
    Action[] shutdownActions = new Action[serverControllers.Count];
    ServerController[] serverControllerArray = serverControllers.ToArray();

    for (int i = 0; i < serverControllerArray.Length; i++) {
        shutdownActions[i] = serverControllerArray[i].Shutdown;

    try {
        // No exception is expected in this example, but if one is still thrown from a task,
        // it will be wrapped in AggregateException and propagated to the main thread. See MSDN example
    catch (AggregateException e) {
        Logger.Instance.Log(string.Format("An action has thrown an exception. THIS WAS UNEXPECTED.\n{0}", e.InnerException));
        throw new Exception();

public string InitShutdownOfServers() {
    Queue<ServerController> serverControllers = new Queue<ServerController>();

    try {
        foreach (ServerAdminDetails serverAdminDetail in ServerAdminDetails.QueuedDetails) {

            Type t = Type.GetType(GetType().Namespace + "." + serverAdminDetail.ServerControllerType);
            serverControllers.Enqueue(Activator.CreateInstance(t, serverAdminDetail) as ServerController);
    } catch(Exception e) {
        Logger.Instance.Log("Exception occured while enqueueing the server controllers. Details follow:" +
            NewLine +

    bool ignoreCase = true;
    Synchronicity synchronicity = (Synchronicity)Enum.Parse(typeof (Synchronicity), ConfigReader.Read["Synchronicity"], ignoreCase);

    if(synchronicity == Synchronicity.Synchronous)

    return "InitShutdownOfServers successfully executed.";

In order to place the ServerController‘s on the serverController‘s Queue (line 33)… via the iterator provided by the Queue of ServerAdminDetails returned from
the static QueuedDetails property of ServerAdminDetails,
We must first instantiate the single instance of ServerAdminDetails,
which is what line 30 does.

In order for ServerAdminDetails to be constructed, the static _queue member (which is a Lazy of Queue of ServerAdminDetails) must be initialized first.
In order for the _queue member to be initialized with a Queue of ServerAdminDetails, the static QueueServersForShutdown procedure must be called.

This is where we pull out the values from the BinaryMist.PowerOffUPSGuests.dll.config shown above with the help of the ConfigReader.
As you can see, we iterate through the config file, building up the Queue of ServerAdminDetails  until we’ve read all the appropriate values.
Each pass through the loop instantiates a new ServerAdminDetails (non singleton because of inside class scope) with the values we pulled from the config file.

The ServerAdminDetails

    /// <summary>
    /// Provides the administration details of the servers listed in the BinaryMist.PowerOffUPSGuests.dll.config file.
    /// </summary>
    public class ServerAdminDetails {

        #region singleton initialization
        private static readonly Lazy<Queue<ServerAdminDetails>> _queue = new Lazy<Queue<ServerAdminDetails>>(QueueServersForShutdown);

        private ServerAdminDetails(string serverController, string serverName, string serverPort, string userName, byte[] serverCredential) {
            ServerControllerType = serverController;
            ServerName = serverName;
            ServerPort = serverPort;
            UserName = userName;
            Password = serverCredential;

        /// <summary>
        /// Provides the process wide single instance queue of each servers admin details.
        /// </summary>
        public static Queue<ServerAdminDetails> QueuedDetails {
            get {
                return _queue.Value;

        private static Queue<ServerAdminDetails> ServersQueuedForShutdown { get; set; }

        private static byte[] GetMyCredential(string pWFileName) {
            try {
                return File.ReadAllBytes(pWFileName);
            } catch(Exception e) {
            string error = string.Format(
                "Error occured while instantiating a ServerAdminDetails instance for queueing. Specificaly while reading bytes from the following file: {0}{1}Exception details follow.{1}{2}",
                throw new Exception(error);

        private static Queue<ServerAdminDetails> QueueServersForShutdown() {

            ServersQueuedForShutdown = new Queue<ServerAdminDetails>();

            const int firstServerIndex = 0;
            int serverCount = firstServerIndex;
            string empty = string.Empty;

                string controller = ConfigReader.Read["Controller" + serverCount];
                string server = ConfigReader.Read["Server" + serverCount];
                string serverPort = ConfigReader.Read["ServerPort" + serverCount];
                string serverUser = ConfigReader.Read["ServerUser" + serverCount];
                string serverUserPwFile = ConfigReader.Read["ServerUserPwFile" + serverCount];

                if (controller == empty || server == empty || serverPort == empty || serverUser == empty || serverUserPwFile == empty)

                    new ServerAdminDetails(

                Logger.Instance.Log (
                    string.Format (
                        "Server admin details of Controller: {0}, Server: {1}, ServerPort: {2}, ServerUser: {3}, ServerUserPwFile: {4} added to queued element number {5}.",

            } while (true);
            return ServersQueuedForShutdown;

        /// <summary>
        /// Retreives the entropy found in the BinaryMist.PowerOffUPSGuests.dll.config file, used to encrypt all the passwords.
        /// </summary>
        /// <returns>byte[]</returns>
        public static byte[] CredentialEntropy() {
            string[] numbers = ConfigReader.Read["CredentialEntropy"].Split(',');
            byte[] entropy = new byte[numbers.Length];
            for (int i = 0; i < numbers.Length; i++) {
                entropy[i] = Byte.Parse(numbers[i]);
            return entropy;

        /// <summary>
        /// The name of the ServerController child type.
        /// </summary>
        internal string ServerControllerType { get; private set; }

        /// <summary>
        /// The name of the server
        /// </summary>
        internal string ServerName { get; private set; }

        /// <summary>
        /// The port of the server
        /// </summary>
        internal string ServerPort { get; private set; }

        /// <summary>
        /// The user name for the server
        /// </summary>
        internal string UserName { get; private set; }

        /// <summary>
        /// The password for the user
        /// </summary>
        internal byte[] Password { get; private set; }

Back to line 33 of the Initiator.
Now that we can access each ServerAdminDetails within the Queue of ServerAdminDetails via the Queue iterator provided by ServerAdminDetails.QueuedDetails.
We can create the ServerController child types using the late bound Activator.CreateInstance method, based on the ServerAdminDetails.ServerControllerType.
A reference to each ServerController child instance is added to the serverControllers queue.
The Shutdown procedure for each ServerController child is then called.

The ServerController

Notice the constructor which has been called by the child’s constructor, calls back to the child’s AssembleRequests procedure before completing.

    /// <summary>
    /// Controls the process of shutting down the associated server.
    /// </summary>
    /// <remarks>
    /// An instance of this class is created indirectly via the more specific concrete creators for each server that requires shutdown.
    /// Plays the part of the Creator, in the Factory Method pattern.
    /// </remarks>
    internal abstract class ServerController {

        protected static readonly string NewLine = Initiator.NewLine;

        protected enum RequestMethod {

        /// <summary>
        /// Constructor for the <see cref="ServerController"/> class.
        /// Called via the more specific children to initialize the less specific members.
        /// </summary>
        /// <param name="serverAdminDetails">
        /// The details required to create the messages that need to be sent to the server in order to perform the shutdown.</param>
        public ServerController(ServerAdminDetails serverAdminDetails) {
            ServerAdminDetails = serverAdminDetails;
            RequestAssembler = new RequestAssembler();
            SoapEnvelopes = new Queue<XmlDocument>();

        protected ServerAdminDetails ServerAdminDetails { get; set; }

        protected RequestAssembler RequestAssembler { get; set; }

        /// <summary>
        /// Reference a <see cref="System.Collections.Generic.Queue{System.Xml.XmlDocument}">queue</see> of soap envelopes.
        /// used by the children of this class to send to the server.
        /// </summary>
        public Queue<XmlDocument> SoapEnvelopes { get; protected set; }

        /// <summary>
        /// Initial preparation of messages that will be sent to the server to perform shutdown.
        /// </summary>
        /// <remarks>Factory method.</remarks>
        public abstract void AssembleRequests();

        /// <summary>
        /// Completes the compilation of the sequence of messages that need to be sent to the server in order to perform the shutdown.
        /// Sends the messages.
        /// </summary>
        public abstract void Shutdown();

        protected void NotifyOfShutdown() {
                    "{0}.Shutdown on server: {1} has now been executed.",

        protected bool SimplePing() {
            string serverName = ServerAdminDetails.ServerName;
            Logger.Instance.Log(string.Format("Performing Ping test on server: {0}", serverName));
            Ping pingSender = new Ping();
            int pingRetry = 3;
            PingReply reply = null;
            for (int i = 0; i < pingRetry; i++) {
                try {
                    //may take a couple of tries, as may time out due to arp delay
                    Logger.Instance.Log(string.Format("Initiating Ping number {0} of {1} on server: {2}. ", i + 1, pingRetry, serverName));
                    reply = pingSender.Send(serverName);

                    if (reply.Status == IPStatus.Success) break;

                } catch (Exception e) {

            bool optionsAvailable = reply.Options != null;
            string noOptions = "No Options available";

                "Reply status for server: " + serverName + " was " + reply.Status + ". " + NewLine +
                "Address: " + reply.Address.ToString() + ". " + NewLine +
                "RoundTrip time: " + reply.RoundtripTime + ". " + NewLine +
                "Time to live: " + ((optionsAvailable) ? reply.Options.Ttl.ToString() : noOptions) + ". " + NewLine +
                "Don't fragment: " + ((optionsAvailable) ? reply.Options.DontFragment.ToString() : noOptions) + ". " + NewLine +
                "Buffer size: " + reply.Buffer.Length + ". "

            return reply.Status == IPStatus.Success;

The ServerController children

The AssembleRequests constructs as much of the SOAP envelopes as it can,
without knowing all the information that the target server will provide to be able to complete the messages before being sent.
The RequestAssembler‘s CreateSoapEnvelope does the assembly of the SOAP envelope.
You’ll notice that the RequestAssembler‘s CreateLoginSoapEnvelope takes an extra argument.
The ServerAdminDetails is passed so that the target server’s credentials can be included in the SOAP envelope.
The SOAP envelopes are then queued ready for dispatch.

Now when line 02 or 11 of the Initiator is executed,
line 143 of the VMServerController will be called. That’s Shutdown.
Then we dequeue, send request, and process the response in DequeueSendRequestProcessResponse.
Passing in an optional parameter of Action of HttpWebResponse (the lambda).
From DequeueSendRequestProcessResponse,
we dequeue each SOAP envelope and call CreateWebRequest,
which in-turn, palms the work it knows about to the less specific RequestAssembler‘s CreateWebRequest as a lambda.
Now in DequeueSendRequestProcessResponse, when we get our initialized HttpWebRequest back,
We pass both the SOAP envelope and the HttpWebRequest to the RequestAssembler‘s InsertSoapEnvelopeIntoWebRequest‘s procedure to do the honors.

    /// <summary>
    /// Controls the process of shutting down the associated vSphere server.
    /// </summary>
    /// <remarks>
    /// Plays the part of the Concrete Creator, in the Factory Method pattern.
    /// </remarks>
    internal class VMServerController : ServerController {

        private static string _operationIDEndTag = "</operationID>";
        private static string _operationIDTags = "<operationID>" + _operationIDEndTag;
        private uint _operationIDaVal = 0xAC1CF80C;
        private uint _operationIDbVal = 0x00000000;
        private const int EstimatedHeaderSize = 45;

        private enum RequestType {
            Hello, HandShake, Login, Shutdown

        private string _host;
        private string _uRL;
        private readonly string _action = @"""urn:internalvim25/4.1""";
        private readonly string _userAgent = @"VMware VI Client/4.0.0";
        private KeyValuePair<string, string> _cookie;

        public VMServerController(ServerAdminDetails serverAdminDetails) : base(serverAdminDetails) {


        /// <summary>
        /// Loads the <see cref="ServerController.SoapEnvelopes">SoapEnvelopes</see> with the sequence of messages
        /// that need to be sent to the server in order to perform the shutdown.
        /// </summary>
        /// <remarks>
        /// Factory method implementation
        /// </remarks>
        public override void AssembleRequests() {
            _host = "https://" + ServerAdminDetails.ServerName + ":" +ServerAdminDetails.ServerPort;
            _uRL = "/sdk";

        private string InitialHeaderContent() {
            StringBuilder headerContent = new StringBuilder(_operationIDTags, EstimatedHeaderSize);
            headerContent.Insert(headerContent.ToString().IndexOf(_operationIDEndTag), _operationIDaVal.ToString("X8") + "-" + (++_operationIDbVal).ToString("X8"));
            return headerContent.ToString();

        private XmlDocument CreateHelloEnvelope() {
            string bodyContent = @"
    <RetrieveServiceContent xmlns=""urn:internalvim25"">
      <_this xsi:type=""ManagedObjectReference"" type=""ServiceInstance"" serverGuid="""">ServiceInstance</_this>
            return RequestAssembler.CreateSoapEnvelope(InitialHeaderContent(), bodyContent);

        private XmlDocument CreateHandshakeEnvelope() {
            string bodyContent = @"
    <RetrieveInternalContent xmlns=""urn:internalvim25"">
      <_this xsi:type=""ManagedObjectReference"" type=""ServiceInstance"" serverGuid="""">ServiceInstance</_this>
            return RequestAssembler.CreateSoapEnvelope(InitialHeaderContent(), bodyContent);

        private XmlDocument CreateLoginEnvelope() {
            string bodyContent = @"
    <Login xmlns=""urn:internalvim25"">
      <_this xsi:type=""ManagedObjectReference"" type=""SessionManager"" serverGuid="""">ha-sessionmgr</_this>
            try {
                // As VMware insist on putting credentials in the SOAP body what else can we do?
                return RequestAssembler.CreateLoginSoapEnvelope(InitialHeaderContent(), bodyContent, ServerAdminDetails);
            } catch(InvalidCredentialException e) {
                string error = string.Format(
                    "Error occured during a call to CreateLoginSoapEnvelope, for server: {0}.{1}Exception details follow.{1}{2}",
                throw new Exception(error);

        private XmlDocument CreateShutdownEnvelope() {
            string bodyContent = @"
    <ShutdownHost_Task xmlns=""urn:internalvim25"">
      <_this xsi:type=""ManagedObjectReference"" type=""HostSystem"" serverGuid="""">ha-host</_this>
            return RequestAssembler.CreateSoapEnvelope(InitialHeaderContent(), bodyContent);

        private HttpWebRequest CreateWebRequest(string uRL, KeyValuePair<string, string> cookie) {
            return RequestAssembler.CreateWebRequest(
                    request.Method = RequestMethod.Post.ToString();
                    request.UserAgent = _userAgent;
                    request.ContentType = "text/xml; charset=\"utf-8\"";
                    request.Headers.Add("SOAPAction", _action);
                    request.Accept = "text/xml";
                    request.KeepAlive = true;

                    if (!string.IsNullOrEmpty(cookie.Key))
                        request.Headers.Add("Cookie", cookie.Key + "=" + cookie.Value);

        private void DequeueSendRequestProcessResponse(RequestType requestType, KeyValuePair<string, string> cookie, Action<HttpWebResponse> additionalResponseProcessing = null) {
            Logger.Instance.Log(string.Format("Will now attempt sending {0} message to server: {1}", requestType, ServerAdminDetails.ServerName));
            XmlDocument soapEnvelope = SoapEnvelopes.Dequeue();
            HttpWebRequest httpWebRequest = CreateWebRequest(_host + _uRL, cookie);
            RequestAssembler.InsertSoapEnvelopeIntoWebRequest(soapEnvelope, httpWebRequest);

            string soapResult;
            using (HttpWebResponse response = (HttpWebResponse)httpWebRequest.GetResponse())
            using (Stream responseStream = response.GetResponseStream())
            using (StreamReader streamReader = new StreamReader(responseStream)) {
                //pull out the bits we need for the next request.

                if (additionalResponseProcessing != null) {

                soapResult = streamReader.ReadToEnd();

        /// <summary>
        /// Perform the shutdown of the server specified in the <see cref="ServerAdminDetails">server admin details</see>.
        /// </summary>
        public override void Shutdown() {

            bool serverOnline = SimplePing();
                    ? string.Format("Initiating sending of {0} to server: {1}", RequestType.Hello, ServerAdminDetails.ServerName)
                    : string.Format("Could not reach server: {0}. Aborting shutdown of server: {0}", ServerAdminDetails.ServerName)

            ServicePointManager.ServerCertificateValidationCallback += ValidateRemoteCertificate;

            KeyValuePair<string, string> emptyCookie = new KeyValuePair<string, string>();
                (response)=> {
                    string[] setCookieElementsResponse = response.Headers["Set-Cookie"].Split(new[] { "\"" }, StringSplitOptions.RemoveEmptyEntries);
                    _cookie = new KeyValuePair<string, string>(setCookieElementsResponse[0].TrimEnd('='), "\"" + setCookieElementsResponse[1] + "\"");
            DequeueSendRequestProcessResponse(RequestType.HandShake, _cookie);
            DequeueSendRequestProcessResponse(RequestType.Login, _cookie);
            DequeueSendRequestProcessResponse(RequestType.Shutdown, _cookie);

        private static string RemoteCertificateDetails(X509Certificate certificate) {
            return string.Format(
                "Details of the certificate provided by the remote party are as follows:" + NewLine +
                "Subject: {0}" + NewLine +
                "Issuer: {1}",

The RequestAssembler

    /// <summary>
    /// Provides ancillary operations for <see cref="ServerController">server controllers</see>
    /// that assist in the creation of the requests intended for dispatch to the servers requiring shutdown.
    /// </summary>
    internal class RequestAssembler {

        private static string _soapEnvelope = @"<soap:Envelope xmlns:xsd='' xmlns:xsi='' xmlns:soap=''>

        /// <summary>
        /// Produces a SOAP envelope in XML form with the server admins user credentials
        /// </summary>
        /// <param name="headerContent">Content targeted for between the header tags.</param>
        /// <param name="bodyContent">Content targeted for between the body tags.</param>
        /// <param name="serverAdminDetails">The <see cref="ServerAdminDetails"/> instance used to access the user name and password.</param>
        /// <returns>The SOAP envelope.</returns>
        public XmlDocument CreateLoginSoapEnvelope(string headerContent, string bodyContent, ServerAdminDetails serverAdminDetails) {

            string failMessage = "The credentials were not correctly set. Username: {0} Password byte count: {1}";
            if (string.IsNullOrEmpty(serverAdminDetails.UserName) || serverAdminDetails.Password.Length < 1)
                throw new InvalidCredentialException(string.Format(failMessage, serverAdminDetails.UserName, serverAdminDetails.Password.Length));

            StringBuilder bodyContentBuilder= new StringBuilder(bodyContent, bodyContent.Length + 10);


            return CreateSoapEnvelope(headerContent, bodyContentBuilder.ToString());

        private string decryptedCredential(ServerAdminDetails serverAdminDetails) {
            try {
                return new ASCIIEncoding().GetString(
            } catch(CryptographicException e) {

                // Retrieve the exception that caused the current
                // CryptographicException exception.
                Exception innerException = e.InnerException;
                string innerExceptionMessage = "";
                if (innerException != null) {
                    innerExceptionMessage = innerException.ToString();

                // Retrieve the message that describes the exception.
                string message = e.Message;

                // Retrieve the name of the application that caused the exception.
                string exceptionSource = e.Source;

                // Retrieve the call stack at the time the exception occured.
                string stackTrace = e.StackTrace;

                // Retrieve the method that threw the exception.
                System.Reflection.MethodBase targetSite = e.TargetSite;
                string siteName = targetSite.Name;

                // Retrieve the entire exception as a single string.
                string entireException = e.ToString();

                // Get the root exception that caused the current
                // CryptographicException exception.
                Exception baseException = e.GetBaseException();
                string baseExceptionMessage = "";
                if (baseException != null) {
                    baseExceptionMessage = baseException.Message;

                    "Caught an unexpected exception:" + Initiator.NewLine
                    + entireException + Initiator.NewLine
                    + Initiator.NewLine
                    + "Properties of the exception are as follows:" + Initiator.NewLine
                    + "Message: " + message + Initiator.NewLine
                    + "Source: " + exceptionSource + Initiator.NewLine
                    + "Stack trace: " + stackTrace + Initiator.NewLine
                    + "Target site's name: " + siteName + Initiator.NewLine
                    + "Base exception message: " + baseExceptionMessage + Initiator.NewLine
                    + "Inner exception message: " + innerExceptionMessage + Initiator.NewLine

        /// <summary>
        /// Produces a SOAP envelope in XML form.
        /// </summary>
        /// <param name="headerContent">Content targeted for between the header tags.</param>
        /// <param name="bodyContent">Content targeted for between the body tags.</param>
        /// <returns><see cref="System.Xml.XmlDocument">The SOAP envelope</see>.</returns>
        public XmlDocument CreateSoapEnvelope(string headerContent, string bodyContent) {

            StringBuilder sb = new StringBuilder(_soapEnvelope);

            try {
                sb.Insert(sb.ToString().IndexOf(Initiator.NewLine + "    " + "</soap:Header>"), headerContent);
                sb.Insert(sb.ToString().IndexOf(Initiator.NewLine + "    " + "</soap:Body>"), bodyContent);
            } catch(Exception e) {

            XmlDocument soapEnvelopeXml = new XmlDocument();

            return soapEnvelopeXml;

        /// <summary>
        /// Creates a web request based on the url passed in.
        /// </summary>
        /// <param name="url">The target URL of the server that will be shutdown.</param>
        /// <param name="additionalWebRequestManipulation">delegate of type
        /// <see cref="System.Action{HttpWebRequest}">Action{HttpWebRequest}</see>.
        /// This is used to take additional tasking defined in the calling procedure.
        /// This procedure creates the web request,
        /// and passes it into this parameter for the additional initialization work to be performed on the web request.
        /// </param>
        /// <returns>
        /// An initialized <see cref="System.Net.HttpWebRequest">web request</see>,
        /// ready to have a <see cref="System.Xml.XmlDocument">soap envelope</see> inserted.</returns>
        public HttpWebRequest CreateWebRequest(string url, Action<HttpWebRequest> additionalWebRequestManipulation = null) {
            HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(url);

            if(additionalWebRequestManipulation != null) {
            return webRequest;

        /// <summary>
        /// Insert the <see cref="System.Xml.XmlDocument">soap envelope</see> into the <see cref="System.Net.HttpWebRequest">web request</see>.
        /// </summary>
        /// <param name="soapEnvelopeXml">
        /// The <see cref="System.Xml.XmlDocument">soap envelope</see> to be inserted into the
        /// <see cref="System.Net.HttpWebRequest">web request</see>.
        /// </param>
        /// <param name="webRequest">The <see cref="System.Net.HttpWebRequest">web request</see> that the
        /// <see cref="System.Xml.XmlDocument"/>soap envelope</see> is inserted into.
        /// </param>
        public void InsertSoapEnvelopeIntoWebRequest(XmlDocument soapEnvelopeXml, HttpWebRequest webRequest) {
            using (Stream stream = webRequest.GetRequestStream()) {

        private static void InsertByteArrayIntoWebRequest(byte[] postData, HttpWebRequest webRequest) {
            using (Stream stream = webRequest.GetRequestStream()) {
                stream.Write(postData, 0, postData.Length);
            webRequest.ContentLength = postData.Length;

        /// <summary>
        /// Inserts the credentials from the <see cref="ServerAdminDetails">server admmin details</see> into the
        /// <see cref="System.Net.HttpWebRequest">web request</see> supplied.
        /// </summary>
        /// <param name="serverAdminDetails">
        /// The <see cref="ServerAdminDetails">server admin details</see>
        /// containing the information for the server that the request will be sent to.
        /// </param>
        /// <param name="webRequest">
        /// The <see cref="System.Net.HttpWebRequest">web request</see> that will have the server administration credentials inserted.
        /// </param>
        public void InsertCredentialsIntoWebRequest(ServerAdminDetails serverAdminDetails, HttpWebRequest webRequest) {
                new ASCIIEncoding().GetBytes("username=" + serverAdminDetails.UserName + "&password=" + decryptedCredential(serverAdminDetails)),

Let me know if any of this is unclear, and requires additional explanation.

Once again, the full source code can be found here.