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  • prevent IE Mobile from scaling web pages automatically

    - by Adam
    I have not been able to get IE mobile to stop automatically resizing my site design. I am using three stylesheets with media queries to display the site differently on different device screens. I've included the meta tag so it shows the mobile stylesheet on IE mobile but it keeps setting the viewport at 320X480 instead of using the actual size of 480X800. How can I force it to display at the actual screen size instead of scaling for a smaller resolution?

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  • Setting custom SQL in django admin

    - by eugene y
    I'm trying to set up a proxy model in django admin. It will represent a subset of the original model. The code from models.py: class MyManager(models.Manager): def get_query_set(self): return super(MyManager, self).get_query_set().filter(some_column='value') class MyModel(OrigModel): objects = MyManager() class Meta: proxy = True Now instead of filter() I need to use a complex SELECT statement with JOINS. What's the proper way to inject it wholly to the custom manager?

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  • Redirect to login page automatically after some time

    - by ASD
    How can we redirect to login page automatically after some time? I have a requirement to redirect to login page if the current page is idle for 10 minutes in Java/JSP. I tried to use <meta http-equiv="refresh" content="120;url=./login.html"> tag. This works only when I click on any link but not automatically after 2 mins(120secs). Can anyone tell me how to redirect to login page automatically?

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  • IE showing "decimal" instead of "comma"

    - by John Stewart
    I am having an issue with a slider (implemented using Prototype) and IE7. Upon the slider value change I update a with the value such as "420,000". Now on all browsers other than IE7 this is display correctly. But on IE7 it is displayed as "420.000" .. my question is how did the "," become "." the page has UTF-8 meta tag. Any help?

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  • Data from two tables without repeating data from the first?

    - by Aran
    I have two tables. Users table and Users Meta Table I am looking for a way to get all the information out of both tables with one query. But without repeating the information from Users table. This is all information relating to the users id number as well. So for example user_id = 1. Is there a way to query the database and collect all the information I from both tables without repeating the information from the first?

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  • Django menu item sorting

    - by doktorno
    Hi i've got MenuItem model : MenuItem(models.Model) name=models.CharField(max_length=50) url = models.URLField() position = models.IntegerField() Class Meta: ordering =['position'] then i'm retriving it by MenuItem.objects.all() My question is how can i make any user friendly interface in admin panel to allow sorting MenuItems - for example list with + and - buttons to move MenuItem up and down ....

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  • How do I search the MediaStore for a specific directory instead of entire external storage?

    - by Nick Lopez
    In my app I have an option that allows users to browse for audio files on their phone to add to the app. I am having trouble however with creating a faster way of processing the query code. Currently it searches the entire external storage and causes the phone to prompt a force close/wait warning. I would like to take the code I have posted below and make it more efficient by either searching in a specific folder on the phone or by streamlining the process to make the file search quicker. I am not sure how to do this however. Thanks! public class BrowseActivity extends DashboardActivity implements OnClickListener, OnItemClickListener { private List<Sound> soundsInDevice = new ArrayList<Sound>(); private List<Sound> checkedList; private ListView browsedList; private BrowserSoundAdapter adapter; private long categoryId; private Category category; private String currentCategoryName; private String description; // private Category newCategory ; private Button doneButton; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_browse); checkedList = new ArrayList<Sound>(); browsedList = (ListView) findViewById(android.R.id.list); doneButton = (Button) findViewById(R.id.doneButton); soundsInDevice = getMediaSounds(); if (soundsInDevice.size() > 0) { adapter = new BrowserSoundAdapter(this, R.id.browseSoundName, soundsInDevice); } else { Toast.makeText(getApplicationContext(), getString(R.string.no_sounds_available), Toast.LENGTH_SHORT) .show(); } browsedList.setAdapter(adapter); browsedList.setOnItemClickListener(this); doneButton.setOnClickListener(this); } private List<Sound> getMediaSounds() { List<Sound> mediaSoundList = new ArrayList<Sound>(); ContentResolver cr = getContentResolver(); String[] projection = {MediaStore.Audio.Media._ID, MediaStore.Audio.Media.DISPLAY_NAME, MediaStore.Audio.Media.TITLE, MediaStore.Audio.Media.DATA, MediaStore.Audio.Media.DURATION}; final Uri uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; Log.v("MediaStore.Audio.Media.EXTERNAL_CONTENT_URI", "" + uri); final Cursor cursor = cr.query(uri, projection, null, null, null); int n = cursor.getCount(); Log.v("count", "" + n); if (cursor.moveToFirst()) { do { String soundName = cursor .getString(cursor .getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME)); Log.v("soundName", "" + soundName); String title = cursor .getString(cursor .getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE)); Log.v("title", "" + title); String path = cursor.getString(cursor .getColumnIndexOrThrow(MediaStore.Audio.Media.DATA)); Log.v("path", "" + path); Sound browsedSound = new Sound(title, path, false, false, false, false, 0); Log.v("browsedSound", "" + browsedSound); mediaSoundList.add(browsedSound); Log.v("mediaSoundList", "" + mediaSoundList.toString()); } while (cursor.moveToNext()); } return mediaSoundList; } public class BrowserSoundAdapter extends ArrayAdapter<Sound> { public BrowserSoundAdapter(Context context, int textViewResourceId, List<Sound> objects) { super(context, textViewResourceId, objects); } @Override public View getView(final int position, View convertView, ViewGroup parent) { ViewHolder viewHolder; View view = convertView; LayoutInflater inflater = getLayoutInflater(); if (view == null) { view = inflater.inflate(R.layout.list_item_browse, null); viewHolder = new ViewHolder(); viewHolder.soundNameTextView = (TextView) view .findViewById(R.id.browseSoundName); viewHolder.pathTextView = (TextView) view .findViewById(R.id.browseSoundPath); viewHolder.checkToAddSound = (CheckBox) view .findViewById(R.id.browse_checkbox); view.setTag(viewHolder); } else { viewHolder = (ViewHolder) view.getTag(); } final Sound sound = soundsInDevice.get(position); if (sound.isCheckedState()) { viewHolder.checkToAddSound.setChecked(true); } else { viewHolder.checkToAddSound.setChecked(false); } viewHolder.soundNameTextView.setText(sound.getName()); viewHolder.pathTextView.setText(sound.getUri()); viewHolder.checkToAddSound .setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { CheckBox cb = (CheckBox) v .findViewById(R.id.browse_checkbox); boolean checked = cb.isChecked(); boolean newValue = checked; updateView(position, newValue); doneButtonStatus(checkedList.size()); } }); return view; } } // Adapter view holder class private class ViewHolder { private TextView soundNameTextView; private TextView pathTextView; private CheckBox checkToAddSound; } // done button On Click @Override public void onClick(View view) { boolean status = getIntent().getBooleanExtra("FromAddCat", false); Log.v("for add category","enters in if"); if(status){ Log.v("for add category","enters in if1"); currentCategoryName = getIntent().getStringExtra("categoryName"); description = getIntent().getStringExtra("description"); boolean existCategory = SQLiteHelper.getCategoryStatus(currentCategoryName); if (!existCategory) { category = new Category(currentCategoryName, description, false); category.insert(); category.update(); Log.v("for add category","enters in if2"); } }else{ categoryId = getIntent().getLongExtra("categoryId",-1); category = SQLiteHelper.getCategory(categoryId); } for (Sound checkedsound : checkedList) { checkedsound.setCheckedState(false); checkedsound.insert(); category.getSounds().add(checkedsound); final Intent intent = new Intent(this, CategoriesActivity.class); finish(); startActivity(intent); } } @Override public void onItemClick(AdapterView<?> arg0, View view, int position, long arg3) { boolean checked = true; boolean newValue = false; CheckBox cb = (CheckBox) view.findViewById(R.id.browse_checkbox); if (cb.isChecked()) { cb.setChecked(!checked); newValue = !checked; } else { cb.setChecked(checked); newValue = checked; } updateView(position, newValue); doneButtonStatus(checkedList.size()); } private void doneButtonStatus(int size) { if (size > 0) { doneButton.setEnabled(true); doneButton.setBackgroundResource(R.drawable.done_button_drawable); } else { doneButton.setEnabled(false); doneButton.setBackgroundResource(R.drawable.done_btn_disabled); } } private void updateView(int index, boolean newValue) { System.out.println(newValue); Sound sound = soundsInDevice.get(index); if (newValue == true) { checkedList.add(sound); sound.setCheckedState(newValue); } else { checkedList.remove(sound); sound.setCheckedState(newValue); } } }

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  • PHP TTF/OTF Reader

    - by Abs
    Hello all, Is anyone aware of a font reader class where I can pass in a font file (ttf or otf) and I can find out the font name, the model, artist etc. The meta data really. Thanks all for any help

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  • Should I create a new extension for an xml file?

    - by macleojw
    I'm working with a data model stored in XML files. I want to create some metadata for the model and store it alongside, but would like to be able to distinguish between the two. The data model is imported into some software from time to time and we don't want it to try to import the meta data files. To get round this, I've been thinking of creating a new extension for the metadata xml files (say .mdml). Is this good practice?

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  • Disabling the "save password" prompt in web browsers

    - by torrtruk
    hi guys. How do I disable the save password prompt in web browsers whenever I'm submitting a form. I've seen a few bank sites where this doesn't come up. Are they doing it through JS or there any http headers or HTML meta tags available to achieve this? I'm trying to do this for a mobile application. Please pour your ideas.

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  • How do I set prifix to django contrib tables names?

    - by Software Enthusiastic
    HI One of my requirement is to have prefix on all the tables of the django based project (Because db is hosted on shared server). I have used db_table Meta option to set the prefix for the tables which I have created. Now my query is how do I set the prefix for tables provided by django.contrib. Instead of auth_group django should create prefix_auth_group.... How do I do that? Thank you very much...

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  • sqlalchemy natural sorting

    - by teggy
    Currently, i am querying with this code: meta.Session.query(Label).order_by(Label.name).all() and it returns me objects sorted by Label.name in this manner ['1','7','1a','5c']. Is there a way i can have the objects returned in the order with their Label.name sorted like this ['1','1a','5c','7'] Thanks!

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  • How to tell if JSON object is empty in jQuery

    - by GrantU
    I have the following JSON: { "meta": { "limit": 20, "next": null, "offset": 0, "previous": null, "total_count": 0 }, "objects": [] } I'm interested in objects: I want to know if objects is empty and show an alert: something like this: success: function (data) { $.each(data.objects, function () { if data.objects == None alert(0) else :alert(1) });

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  • recaptcha problem please help me

    - by moustafa
    please see the following code // redirect to success page if ($success){ header( 'Location: ../Scripts/_lib/phpmailer-fe.php'); } else{ print "<meta http-equiv="refresh" content="0;URL=error.html">"; } its not working

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  • Haskell mutability in compiled state?

    - by pile of junk
    I do not know much about Haskell, but from what I have read about the mutability of computations (e.g: functions returning functions, complex monads and functions, etc.) it seems like you can do a lot of meta-programming, even at runtime. How can Haskell, if everything like functions and monads are so complex, compile to machine code and retain all this?

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  • A way of doing real-world test-driven development (and some thoughts about it)

    - by Thomas Weller
    Lately, I exchanged some arguments with Derick Bailey about some details of the red-green-refactor cycle of the Test-driven development process. In short, the issue revolved around the fact that it’s not enough to have a test red or green, but it’s also important to have it red or green for the right reasons. While for me, it’s sufficient to initially have a NotImplementedException in place, Derick argues that this is not totally correct (see these two posts: Red/Green/Refactor, For The Right Reasons and Red For The Right Reason: Fail By Assertion, Not By Anything Else). And he’s right. But on the other hand, I had no idea how his insights could have any practical consequence for my own individual interpretation of the red-green-refactor cycle (which is not really red-green-refactor, at least not in its pure sense, see the rest of this article). This made me think deeply for some days now. In the end I found out that the ‘right reason’ changes in my understanding depending on what development phase I’m in. To make this clear (at least I hope it becomes clear…) I started to describe my way of working in some detail, and then something strange happened: The scope of the article slightly shifted from focusing ‘only’ on the ‘right reason’ issue to something more general, which you might describe as something like  'Doing real-world TDD in .NET , with massive use of third-party add-ins’. This is because I feel that there is a more general statement about Test-driven development to make:  It’s high time to speak about the ‘How’ of TDD, not always only the ‘Why’. Much has been said about this, and me myself also contributed to that (see here: TDD is not about testing, it's about how we develop software). But always justifying what you do is very unsatisfying in the long run, it is inherently defensive, and it costs time and effort that could be used for better and more important things. And frankly: I’m somewhat sick and tired of repeating time and again that the test-driven way of software development is highly preferable for many reasons - I don’t want to spent my time exclusively on stating the obvious… So, again, let’s say it clearly: TDD is programming, and programming is TDD. Other ways of programming (code-first, sometimes called cowboy-coding) are exceptional and need justification. – I know that there are many people out there who will disagree with this radical statement, and I also know that it’s not a description of the real world but more of a mission statement or something. But nevertheless I’m absolutely sure that in some years this statement will be nothing but a platitude. Side note: Some parts of this post read as if I were paid by Jetbrains (the manufacturer of the ReSharper add-in – R#), but I swear I’m not. Rather I think that Visual Studio is just not production-complete without it, and I wouldn’t even consider to do professional work without having this add-in installed... The three parts of a software component Before I go into some details, I first should describe my understanding of what belongs to a software component (assembly, type, or method) during the production process (i.e. the coding phase). Roughly, I come up with the three parts shown below:   First, we need to have some initial sort of requirement. This can be a multi-page formal document, a vague idea in some programmer’s brain of what might be needed, or anything in between. In either way, there has to be some sort of requirement, be it explicit or not. – At the C# micro-level, the best way that I found to formulate that is to define interfaces for just about everything, even for internal classes, and to provide them with exhaustive xml comments. The next step then is to re-formulate these requirements in an executable form. This is specific to the respective programming language. - For C#/.NET, the Gallio framework (which includes MbUnit) in conjunction with the ReSharper add-in for Visual Studio is my toolset of choice. The third part then finally is the production code itself. It’s development is entirely driven by the requirements and their executable formulation. This is the delivery, the two other parts are ‘only’ there to make its production possible, to give it a decent quality and reliability, and to significantly reduce related costs down the maintenance timeline. So while the first two parts are not really relevant for the customer, they are very important for the developer. The customer (or in Scrum terms: the Product Owner) is not interested at all in how  the product is developed, he is only interested in the fact that it is developed as cost-effective as possible, and that it meets his functional and non-functional requirements. The rest is solely a matter of the developer’s craftsmanship, and this is what I want to talk about during the remainder of this article… An example To demonstrate my way of doing real-world TDD, I decided to show the development of a (very) simple Calculator component. The example is deliberately trivial and silly, as examples always are. I am totally aware of the fact that real life is never that simple, but I only want to show some development principles here… The requirement As already said above, I start with writing down some words on the initial requirement, and I normally use interfaces for that, even for internal classes - the typical question “intf or not” doesn’t even come to mind. I need them for my usual workflow and using them automatically produces high componentized and testable code anyway. To think about their usage in every single situation would slow down the production process unnecessarily. So this is what I begin with: namespace Calculator {     /// <summary>     /// Defines a very simple calculator component for demo purposes.     /// </summary>     public interface ICalculator     {         /// <summary>         /// Gets the result of the last successful operation.         /// </summary>         /// <value>The last result.</value>         /// <remarks>         /// Will be <see langword="null" /> before the first successful operation.         /// </remarks>         double? LastResult { get; }       } // interface ICalculator   } // namespace Calculator So, I’m not beginning with a test, but with a sort of code declaration - and still I insist on being 100% test-driven. There are three important things here: Starting this way gives me a method signature, which allows to use IntelliSense and AutoCompletion and thus eliminates the danger of typos - one of the most regular, annoying, time-consuming, and therefore expensive sources of error in the development process. In my understanding, the interface definition as a whole is more of a readable requirement document and technical documentation than anything else. So this is at least as much about documentation than about coding. The documentation must completely describe the behavior of the documented element. I normally use an IoC container or some sort of self-written provider-like model in my architecture. In either case, I need my components defined via service interfaces anyway. - I will use the LinFu IoC framework here, for no other reason as that is is very simple to use. The ‘Red’ (pt. 1)   First I create a folder for the project’s third-party libraries and put the LinFu.Core dll there. Then I set up a test project (via a Gallio project template), and add references to the Calculator project and the LinFu dll. Finally I’m ready to write the first test, which will look like the following: namespace Calculator.Test {     [TestFixture]     public class CalculatorTest     {         private readonly ServiceContainer container = new ServiceContainer();           [Test]         public void CalculatorLastResultIsInitiallyNull()         {             ICalculator calculator = container.GetService<ICalculator>();               Assert.IsNull(calculator.LastResult);         }       } // class CalculatorTest   } // namespace Calculator.Test       This is basically the executable formulation of what the interface definition states (part of). Side note: There’s one principle of TDD that is just plain wrong in my eyes: I’m talking about the Red is 'does not compile' thing. How could a compiler error ever be interpreted as a valid test outcome? I never understood that, it just makes no sense to me. (Or, in Derick’s terms: this reason is as wrong as a reason ever could be…) A compiler error tells me: Your code is incorrect, but nothing more.  Instead, the ‘Red’ part of the red-green-refactor cycle has a clearly defined meaning to me: It means that the test works as intended and fails only if its assumptions are not met for some reason. Back to our Calculator. When I execute the above test with R#, the Gallio plugin will give me this output: So this tells me that the test is red for the wrong reason: There’s no implementation that the IoC-container could load, of course. So let’s fix that. With R#, this is very easy: First, create an ICalculator - derived type:        Next, implement the interface members: And finally, move the new class to its own file: So far my ‘work’ was six mouse clicks long, the only thing that’s left to do manually here, is to add the Ioc-specific wiring-declaration and also to make the respective class non-public, which I regularly do to force my components to communicate exclusively via interfaces: This is what my Calculator class looks like as of now: using System; using LinFu.IoC.Configuration;   namespace Calculator {     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         public double? LastResult         {             get             {                 throw new NotImplementedException();             }         }     } } Back to the test fixture, we have to put our IoC container to work: [TestFixture] public class CalculatorTest {     #region Fields       private readonly ServiceContainer container = new ServiceContainer();       #endregion // Fields       #region Setup/TearDown       [FixtureSetUp]     public void FixtureSetUp()     {        container.LoadFrom(AppDomain.CurrentDomain.BaseDirectory, "Calculator.dll");     }       ... Because I have a R# live template defined for the setup/teardown method skeleton as well, the only manual coding here again is the IoC-specific stuff: two lines, not more… The ‘Red’ (pt. 2) Now, the execution of the above test gives the following result: This time, the test outcome tells me that the method under test is called. And this is the point, where Derick and I seem to have somewhat different views on the subject: Of course, the test still is worthless regarding the red/green outcome (or: it’s still red for the wrong reasons, in that it gives a false negative). But as far as I am concerned, I’m not really interested in the test outcome at this point of the red-green-refactor cycle. Rather, I only want to assert that my test actually calls the right method. If that’s the case, I will happily go on to the ‘Green’ part… The ‘Green’ Making the test green is quite trivial. Just make LastResult an automatic property:     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         public double? LastResult { get; private set; }     }         One more round… Now on to something slightly more demanding (cough…). Let’s state that our Calculator exposes an Add() method:         ...   /// <summary>         /// Adds the specified operands.         /// </summary>         /// <param name="operand1">The operand1.</param>         /// <param name="operand2">The operand2.</param>         /// <returns>The result of the additon.</returns>         /// <exception cref="ArgumentException">         /// Argument <paramref name="operand1"/> is &lt; 0.<br/>         /// -- or --<br/>         /// Argument <paramref name="operand2"/> is &lt; 0.         /// </exception>         double Add(double operand1, double operand2);       } // interface ICalculator A remark: I sometimes hear the complaint that xml comment stuff like the above is hard to read. That’s certainly true, but irrelevant to me, because I read xml code comments with the CR_Documentor tool window. And using that, it looks like this:   Apart from that, I’m heavily using xml code comments (see e.g. here for a detailed guide) because there is the possibility of automating help generation with nightly CI builds (using MS Sandcastle and the Sandcastle Help File Builder), and then publishing the results to some intranet location.  This way, a team always has first class, up-to-date technical documentation at hand about the current codebase. (And, also very important for speeding up things and avoiding typos: You have IntelliSense/AutoCompletion and R# support, and the comments are subject to compiler checking…).     Back to our Calculator again: Two more R# – clicks implement the Add() skeleton:         ...           public double Add(double operand1, double operand2)         {             throw new NotImplementedException();         }       } // class Calculator As we have stated in the interface definition (which actually serves as our requirement document!), the operands are not allowed to be negative. So let’s start implementing that. Here’s the test: [Test] [Row(-0.5, 2)] public void AddThrowsOnNegativeOperands(double operand1, double operand2) {     ICalculator calculator = container.GetService<ICalculator>();       Assert.Throws<ArgumentException>(() => calculator.Add(operand1, operand2)); } As you can see, I’m using a data-driven unit test method here, mainly for these two reasons: Because I know that I will have to do the same test for the second operand in a few seconds, I save myself from implementing another test method for this purpose. Rather, I only will have to add another Row attribute to the existing one. From the test report below, you can see that the argument values are explicitly printed out. This can be a valuable documentation feature even when everything is green: One can quickly review what values were tested exactly - the complete Gallio HTML-report (as it will be produced by the Continuous Integration runs) shows these values in a quite clear format (see below for an example). Back to our Calculator development again, this is what the test result tells us at the moment: So we’re red again, because there is not yet an implementation… Next we go on and implement the necessary parameter verification to become green again, and then we do the same thing for the second operand. To make a long story short, here’s the test and the method implementation at the end of the second cycle: // in CalculatorTest:   [Test] [Row(-0.5, 2)] [Row(295, -123)] public void AddThrowsOnNegativeOperands(double operand1, double operand2) {     ICalculator calculator = container.GetService<ICalculator>();       Assert.Throws<ArgumentException>(() => calculator.Add(operand1, operand2)); }   // in Calculator: public double Add(double operand1, double operand2) {     if (operand1 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand1");     }     if (operand2 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand2");     }     throw new NotImplementedException(); } So far, we have sheltered our method from unwanted input, and now we can safely operate on the parameters without further caring about their validity (this is my interpretation of the Fail Fast principle, which is regarded here in more detail). Now we can think about the method’s successful outcomes. First let’s write another test for that: [Test] [Row(1, 1, 2)] public void TestAdd(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Add(operand1, operand2);       Assert.AreEqual(expectedResult, result); } Again, I’m regularly using row based test methods for these kinds of unit tests. The above shown pattern proved to be extremely helpful for my development work, I call it the Defined-Input/Expected-Output test idiom: You define your input arguments together with the expected method result. There are two major benefits from that way of testing: In the course of refining a method, it’s very likely to come up with additional test cases. In our case, we might add tests for some edge cases like ‘one of the operands is zero’ or ‘the sum of the two operands causes an overflow’, or maybe there’s an external test protocol that has to be fulfilled (e.g. an ISO norm for medical software), and this results in the need of testing against additional values. In all these scenarios we only have to add another Row attribute to the test. Remember that the argument values are written to the test report, so as a side-effect this produces valuable documentation. (This can become especially important if the fulfillment of some sort of external requirements has to be proven). So your test method might look something like that in the end: [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 2)] [Row(0, 999999999, 999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, double.MaxValue)] [Row(4, double.MaxValue - 2.5, double.MaxValue)] public void TestAdd(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Add(operand1, operand2);       Assert.AreEqual(expectedResult, result); } And this will produce the following HTML report (with Gallio):   Not bad for the amount of work we invested in it, huh? - There might be scenarios where reports like that can be useful for demonstration purposes during a Scrum sprint review… The last requirement to fulfill is that the LastResult property is expected to store the result of the last operation. I don’t show this here, it’s trivial enough and brings nothing new… And finally: Refactor (for the right reasons) To demonstrate my way of going through the refactoring portion of the red-green-refactor cycle, I added another method to our Calculator component, namely Subtract(). Here’s the code (tests and production): // CalculatorTest.cs:   [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 0)] [Row(0, 999999999, -999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, -double.MaxValue)] [Row(4, double.MaxValue - 2.5, -double.MaxValue)] public void TestSubtract(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Subtract(operand1, operand2);       Assert.AreEqual(expectedResult, result); }   [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 0)] [Row(0, 999999999, -999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, -double.MaxValue)] [Row(4, double.MaxValue - 2.5, -double.MaxValue)] public void TestSubtractGivesExpectedLastResult(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       calculator.Subtract(operand1, operand2);       Assert.AreEqual(expectedResult, calculator.LastResult); }   ...   // ICalculator.cs: /// <summary> /// Subtracts the specified operands. /// </summary> /// <param name="operand1">The operand1.</param> /// <param name="operand2">The operand2.</param> /// <returns>The result of the subtraction.</returns> /// <exception cref="ArgumentException"> /// Argument <paramref name="operand1"/> is &lt; 0.<br/> /// -- or --<br/> /// Argument <paramref name="operand2"/> is &lt; 0. /// </exception> double Subtract(double operand1, double operand2);   ...   // Calculator.cs:   public double Subtract(double operand1, double operand2) {     if (operand1 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand1");     }       if (operand2 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand2");     }       return (this.LastResult = operand1 - operand2).Value; }   Obviously, the argument validation stuff that was produced during the red-green part of our cycle duplicates the code from the previous Add() method. So, to avoid code duplication and minimize the number of code lines of the production code, we do an Extract Method refactoring. One more time, this is only a matter of a few mouse clicks (and giving the new method a name) with R#: Having done that, our production code finally looks like that: using System; using LinFu.IoC.Configuration;   namespace Calculator {     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         #region ICalculator           public double? LastResult { get; private set; }           public double Add(double operand1, double operand2)         {             ThrowIfOneOperandIsInvalid(operand1, operand2);               return (this.LastResult = operand1 + operand2).Value;         }           public double Subtract(double operand1, double operand2)         {             ThrowIfOneOperandIsInvalid(operand1, operand2);               return (this.LastResult = operand1 - operand2).Value;         }           #endregion // ICalculator           #region Implementation (Helper)           private static void ThrowIfOneOperandIsInvalid(double operand1, double operand2)         {             if (operand1 < 0.0)             {                 throw new ArgumentException("Value must not be negative.", "operand1");             }               if (operand2 < 0.0)             {                 throw new ArgumentException("Value must not be negative.", "operand2");             }         }           #endregion // Implementation (Helper)       } // class Calculator   } // namespace Calculator But is the above worth the effort at all? It’s obviously trivial and not very impressive. All our tests were green (for the right reasons), and refactoring the code did not change anything. It’s not immediately clear how this refactoring work adds value to the project. Derick puts it like this: STOP! Hold on a second… before you go any further and before you even think about refactoring what you just wrote to make your test pass, you need to understand something: if your done with your requirements after making the test green, you are not required to refactor the code. I know… I’m speaking heresy, here. Toss me to the wolves, I’ve gone over to the dark side! Seriously, though… if your test is passing for the right reasons, and you do not need to write any test or any more code for you class at this point, what value does refactoring add? Derick immediately answers his own question: So why should you follow the refactor portion of red/green/refactor? When you have added code that makes the system less readable, less understandable, less expressive of the domain or concern’s intentions, less architecturally sound, less DRY, etc, then you should refactor it. I couldn’t state it more precise. From my personal perspective, I’d add the following: You have to keep in mind that real-world software systems are usually quite large and there are dozens or even hundreds of occasions where micro-refactorings like the above can be applied. It’s the sum of them all that counts. And to have a good overall quality of the system (e.g. in terms of the Code Duplication Percentage metric) you have to be pedantic on the individual, seemingly trivial cases. My job regularly requires the reading and understanding of ‘foreign’ code. So code quality/readability really makes a HUGE difference for me – sometimes it can be even the difference between project success and failure… Conclusions The above described development process emerged over the years, and there were mainly two things that guided its evolution (you might call it eternal principles, personal beliefs, or anything in between): Test-driven development is the normal, natural way of writing software, code-first is exceptional. So ‘doing TDD or not’ is not a question. And good, stable code can only reliably be produced by doing TDD (yes, I know: many will strongly disagree here again, but I’ve never seen high-quality code – and high-quality code is code that stood the test of time and causes low maintenance costs – that was produced code-first…) It’s the production code that pays our bills in the end. (Though I have seen customers these days who demand an acceptance test battery as part of the final delivery. Things seem to go into the right direction…). The test code serves ‘only’ to make the production code work. But it’s the number of delivered features which solely counts at the end of the day - no matter how much test code you wrote or how good it is. With these two things in mind, I tried to optimize my coding process for coding speed – or, in business terms: productivity - without sacrificing the principles of TDD (more than I’d do either way…).  As a result, I consider a ratio of about 3-5/1 for test code vs. production code as normal and desirable. In other words: roughly 60-80% of my code is test code (This might sound heavy, but that is mainly due to the fact that software development standards only begin to evolve. The entire software development profession is very young, historically seen; only at the very beginning, and there are no viable standards yet. If you think about software development as a kind of casting process, where the test code is the mold and the resulting production code is the final product, then the above ratio sounds no longer extraordinary…) Although the above might look like very much unnecessary work at first sight, it’s not. With the aid of the mentioned add-ins, doing all the above is a matter of minutes, sometimes seconds (while writing this post took hours and days…). The most important thing is to have the right tools at hand. Slow developer machines or the lack of a tool or something like that - for ‘saving’ a few 100 bucks -  is just not acceptable and a very bad decision in business terms (though I quite some times have seen and heard that…). Production of high-quality products needs the usage of high-quality tools. This is a platitude that every craftsman knows… The here described round-trip will take me about five to ten minutes in my real-world development practice. I guess it’s about 30% more time compared to developing the ‘traditional’ (code-first) way. But the so manufactured ‘product’ is of much higher quality and massively reduces maintenance costs, which is by far the single biggest cost factor, as I showed in this previous post: It's the maintenance, stupid! (or: Something is rotten in developerland.). In the end, this is a highly cost-effective way of software development… But on the other hand, there clearly is a trade-off here: coding speed vs. code quality/later maintenance costs. The here described development method might be a perfect fit for the overwhelming majority of software projects, but there certainly are some scenarios where it’s not - e.g. if time-to-market is crucial for a software project. So this is a business decision in the end. It’s just that you have to know what you’re doing and what consequences this might have… Some last words First, I’d like to thank Derick Bailey again. His two aforementioned posts (which I strongly recommend for reading) inspired me to think deeply about my own personal way of doing TDD and to clarify my thoughts about it. I wouldn’t have done that without this inspiration. I really enjoy that kind of discussions… I agree with him in all respects. But I don’t know (yet?) how to bring his insights into the described production process without slowing things down. The above described method proved to be very “good enough” in my practical experience. But of course, I’m open to suggestions here… My rationale for now is: If the test is initially red during the red-green-refactor cycle, the ‘right reason’ is: it actually calls the right method, but this method is not yet operational. Later on, when the cycle is finished and the tests become part of the regular, automated Continuous Integration process, ‘red’ certainly must occur for the ‘right reason’: in this phase, ‘red’ MUST mean nothing but an unfulfilled assertion - Fail By Assertion, Not By Anything Else!

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  • 256 Windows Azure Worker Roles, Windows Kinect and a 90's Text-Based Ray-Tracer

    - by Alan Smith
    For a couple of years I have been demoing a simple render farm hosted in Windows Azure using worker roles and the Azure Storage service. At the start of the presentation I deploy an Azure application that uses 16 worker roles to render a 1,500 frame 3D ray-traced animation. At the end of the presentation, when the animation was complete, I would play the animation delete the Azure deployment. The standing joke with the audience was that it was that it was a “$2 demo”, as the compute charges for running the 16 instances for an hour was $1.92, factor in the bandwidth charges and it’s a couple of dollars. The point of the demo is that it highlights one of the great benefits of cloud computing, you pay for what you use, and if you need massive compute power for a short period of time using Windows Azure can work out very cost effective. The “$2 demo” was great for presenting at user groups and conferences in that it could be deployed to Azure, used to render an animation, and then removed in a one hour session. I have always had the idea of doing something a bit more impressive with the demo, and scaling it from a “$2 demo” to a “$30 demo”. The challenge was to create a visually appealing animation in high definition format and keep the demo time down to one hour.  This article will take a run through how I achieved this. Ray Tracing Ray tracing, a technique for generating high quality photorealistic images, gained popularity in the 90’s with companies like Pixar creating feature length computer animations, and also the emergence of shareware text-based ray tracers that could run on a home PC. In order to render a ray traced image, the ray of light that would pass from the view point must be tracked until it intersects with an object. At the intersection, the color, reflectiveness, transparency, and refractive index of the object are used to calculate if the ray will be reflected or refracted. Each pixel may require thousands of calculations to determine what color it will be in the rendered image. Pin-Board Toys Having very little artistic talent and a basic understanding of maths I decided to focus on an animation that could be modeled fairly easily and would look visually impressive. I’ve always liked the pin-board desktop toys that become popular in the 80’s and when I was working as a 3D animator back in the 90’s I always had the idea of creating a 3D ray-traced animation of a pin-board, but never found the energy to do it. Even if I had a go at it, the render time to produce an animation that would look respectable on a 486 would have been measured in months. PolyRay Back in 1995 I landed my first real job, after spending three years being a beach-ski-climbing-paragliding-bum, and was employed to create 3D ray-traced animations for a CD-ROM that school kids would use to learn physics. I had got into the strange and wonderful world of text-based ray tracing, and was using a shareware ray-tracer called PolyRay. PolyRay takes a text file describing a scene as input and, after a few hours processing on a 486, produced a high quality ray-traced image. The following is an example of a basic PolyRay scene file. background Midnight_Blue   static define matte surface { ambient 0.1 diffuse 0.7 } define matte_white texture { matte { color white } } define matte_black texture { matte { color dark_slate_gray } } define position_cylindrical 3 define lookup_sawtooth 1 define light_wood <0.6, 0.24, 0.1> define median_wood <0.3, 0.12, 0.03> define dark_wood <0.05, 0.01, 0.005>     define wooden texture { noise surface { ambient 0.2  diffuse 0.7  specular white, 0.5 microfacet Reitz 10 position_fn position_cylindrical position_scale 1  lookup_fn lookup_sawtooth octaves 1 turbulence 1 color_map( [0.0, 0.2, light_wood, light_wood] [0.2, 0.3, light_wood, median_wood] [0.3, 0.4, median_wood, light_wood] [0.4, 0.7, light_wood, light_wood] [0.7, 0.8, light_wood, median_wood] [0.8, 0.9, median_wood, light_wood] [0.9, 1.0, light_wood, dark_wood]) } } define glass texture { surface { ambient 0 diffuse 0 specular 0.2 reflection white, 0.1 transmission white, 1, 1.5 }} define shiny surface { ambient 0.1 diffuse 0.6 specular white, 0.6 microfacet Phong 7  } define steely_blue texture { shiny { color black } } define chrome texture { surface { color white ambient 0.0 diffuse 0.2 specular 0.4 microfacet Phong 10 reflection 0.8 } }   viewpoint {     from <4.000, -1.000, 1.000> at <0.000, 0.000, 0.000> up <0, 1, 0> angle 60     resolution 640, 480 aspect 1.6 image_format 0 }       light <-10, 30, 20> light <-10, 30, -20>   object { disc <0, -2, 0>, <0, 1, 0>, 30 wooden }   object { sphere <0.000, 0.000, 0.000>, 1.00 chrome } object { cylinder <0.000, 0.000, 0.000>, <0.000, 0.000, -4.000>, 0.50 chrome }   After setting up the background and defining colors and textures, the viewpoint is specified. The “camera” is located at a point in 3D space, and it looks towards another point. The angle, image resolution, and aspect ratio are specified. Two lights are present in the image at defined coordinates. The three objects in the image are a wooden disc to represent a table top, and a sphere and cylinder that intersect to form a pin that will be used for the pin board toy in the final animation. When the image is rendered, the following image is produced. The pins are modeled with a chrome surface, so they reflect the environment around them. Note that the scale of the pin shaft is not correct, this will be fixed later. Modeling the Pin Board The frame of the pin-board is made up of three boxes, and six cylinders, the front box is modeled using a clear, slightly reflective solid, with the same refractive index of glass. The other shapes are modeled as metal. object { box <-5.5, -1.5, 1>, <5.5, 5.5, 1.2> glass } object { box <-5.5, -1.5, -0.04>, <5.5, 5.5, -0.09> steely_blue } object { box <-5.5, -1.5, -0.52>, <5.5, 5.5, -0.59> steely_blue } object { cylinder <-5.2, -1.2, 1.4>, <-5.2, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <5.2, -1.2, 1.4>, <5.2, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <-5.2, 5.2, 1.4>, <-5.2, 5.2, -0.74>, 0.2 steely_blue } object { cylinder <5.2, 5.2, 1.4>, <5.2, 5.2, -0.74>, 0.2 steely_blue } object { cylinder <0, -1.2, 1.4>, <0, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <0, 5.2, 1.4>, <0, 5.2, -0.74>, 0.2 steely_blue }   In order to create the matrix of pins that make up the pin board I used a basic console application with a few nested loops to create two intersecting matrixes of pins, which models the layout used in the pin boards. The resulting image is shown below. The pin board contains 11,481 pins, with the scene file containing 23,709 lines of code. For the complete animation 2,000 scene files will be created, which is over 47 million lines of code. Each pin in the pin-board will slide out a specific distance when an object is pressed into the back of the board. This is easily modeled by setting the Z coordinate of the pin to a specific value. In order to set all of the pins in the pin-board to the correct position, a bitmap image can be used. The position of the pin can be set based on the color of the pixel at the appropriate position in the image. When the Windows Azure logo is used to set the Z coordinate of the pins, the following image is generated. The challenge now was to make a cool animation. The Azure Logo is fine, but it is static. Using a normal video to animate the pins would not work; the colors in the video would not be the same as the depth of the objects from the camera. In order to simulate the pin board accurately a series of frames from a depth camera could be used. Windows Kinect The Kenect controllers for the X-Box 360 and Windows feature a depth camera. The Kinect SDK for Windows provides a programming interface for Kenect, providing easy access for .NET developers to the Kinect sensors. The Kinect Explorer provided with the Kinect SDK is a great starting point for exploring Kinect from a developers perspective. Both the X-Box 360 Kinect and the Windows Kinect will work with the Kinect SDK, the Windows Kinect is required for commercial applications, but the X-Box Kinect can be used for hobby projects. The Windows Kinect has the advantage of providing a mode to allow depth capture with objects closer to the camera, which makes for a more accurate depth image for setting the pin positions. Creating a Depth Field Animation The depth field animation used to set the positions of the pin in the pin board was created using a modified version of the Kinect Explorer sample application. In order to simulate the pin board accurately, a small section of the depth range from the depth sensor will be used. Any part of the object in front of the depth range will result in a white pixel; anything behind the depth range will be black. Within the depth range the pixels in the image will be set to RGB values from 0,0,0 to 255,255,255. A screen shot of the modified Kinect Explorer application is shown below. The Kinect Explorer sample application was modified to include slider controls that are used to set the depth range that forms the image from the depth stream. This allows the fine tuning of the depth image that is required for simulating the position of the pins in the pin board. The Kinect Explorer was also modified to record a series of images from the depth camera and save them as a sequence JPEG files that will be used to animate the pins in the animation the Start and Stop buttons are used to start and stop the image recording. En example of one of the depth images is shown below. Once a series of 2,000 depth images has been captured, the task of creating the animation can begin. Rendering a Test Frame In order to test the creation of frames and get an approximation of the time required to render each frame a test frame was rendered on-premise using PolyRay. The output of the rendering process is shown below. The test frame contained 23,629 primitive shapes, most of which are the spheres and cylinders that are used for the 11,800 or so pins in the pin board. The 1280x720 image contains 921,600 pixels, but as anti-aliasing was used the number of rays that were calculated was 4,235,777, with 3,478,754,073 object boundaries checked. The test frame of the pin board with the depth field image applied is shown below. The tracing time for the test frame was 4 minutes 27 seconds, which means rendering the2,000 frames in the animation would take over 148 hours, or a little over 6 days. Although this is much faster that an old 486, waiting almost a week to see the results of an animation would make it challenging for animators to create, view, and refine their animations. It would be much better if the animation could be rendered in less than one hour. Windows Azure Worker Roles The cost of creating an on-premise render farm to render animations increases in proportion to the number of servers. The table below shows the cost of servers for creating a render farm, assuming a cost of $500 per server. Number of Servers Cost 1 $500 16 $8,000 256 $128,000   As well as the cost of the servers, there would be additional costs for networking, racks etc. Hosting an environment of 256 servers on-premise would require a server room with cooling, and some pretty hefty power cabling. The Windows Azure compute services provide worker roles, which are ideal for performing processor intensive compute tasks. With the scalability available in Windows Azure a job that takes 256 hours to complete could be perfumed using different numbers of worker roles. The time and cost of using 1, 16 or 256 worker roles is shown below. Number of Worker Roles Render Time Cost 1 256 hours $30.72 16 16 hours $30.72 256 1 hour $30.72   Using worker roles in Windows Azure provides the same cost for the 256 hour job, irrespective of the number of worker roles used. Provided the compute task can be broken down into many small units, and the worker role compute power can be used effectively, it makes sense to scale the application so that the task is completed quickly, making the results available in a timely fashion. The task of rendering 2,000 frames in an animation is one that can easily be broken down into 2,000 individual pieces, which can be performed by a number of worker roles. Creating a Render Farm in Windows Azure The architecture of the render farm is shown in the following diagram. The render farm is a hybrid application with the following components: ·         On-Premise o   Windows Kinect – Used combined with the Kinect Explorer to create a stream of depth images. o   Animation Creator – This application uses the depth images from the Kinect sensor to create scene description files for PolyRay. These files are then uploaded to the jobs blob container, and job messages added to the jobs queue. o   Process Monitor – This application queries the role instance lifecycle table and displays statistics about the render farm environment and render process. o   Image Downloader – This application polls the image queue and downloads the rendered animation files once they are complete. ·         Windows Azure o   Azure Storage – Queues and blobs are used for the scene description files and completed frames. A table is used to store the statistics about the rendering environment.   The architecture of each worker role is shown below.   The worker role is configured to use local storage, which provides file storage on the worker role instance that can be use by the applications to render the image and transform the format of the image. The service definition for the worker role with the local storage configuration highlighted is shown below. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="CloudRay" >   <WorkerRole name="CloudRayWorkerRole" vmsize="Small">     <Imports>     </Imports>     <ConfigurationSettings>       <Setting name="DataConnectionString" />     </ConfigurationSettings>     <LocalResources>       <LocalStorage name="RayFolder" cleanOnRoleRecycle="true" />     </LocalResources>   </WorkerRole> </ServiceDefinition>     The two executable programs, PolyRay.exe and DTA.exe are included in the Azure project, with Copy Always set as the property. PolyRay will take the scene description file and render it to a Truevision TGA file. As the TGA format has not seen much use since the mid 90’s it is converted to a JPG image using Dave's Targa Animator, another shareware application from the 90’s. Each worker roll will use the following process to render the animation frames. 1.       The worker process polls the job queue, if a job is available the scene description file is downloaded from blob storage to local storage. 2.       PolyRay.exe is started in a process with the appropriate command line arguments to render the image as a TGA file. 3.       DTA.exe is started in a process with the appropriate command line arguments convert the TGA file to a JPG file. 4.       The JPG file is uploaded from local storage to the images blob container. 5.       A message is placed on the images queue to indicate a new image is available for download. 6.       The job message is deleted from the job queue. 7.       The role instance lifecycle table is updated with statistics on the number of frames rendered by the worker role instance, and the CPU time used. The code for this is shown below. public override void Run() {     // Set environment variables     string polyRayPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), PolyRayLocation);     string dtaPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), DTALocation);       LocalResource rayStorage = RoleEnvironment.GetLocalResource("RayFolder");     string localStorageRootPath = rayStorage.RootPath;       JobQueue jobQueue = new JobQueue("renderjobs");     JobQueue downloadQueue = new JobQueue("renderimagedownloadjobs");     CloudRayBlob sceneBlob = new CloudRayBlob("scenes");     CloudRayBlob imageBlob = new CloudRayBlob("images");     RoleLifecycleDataSource roleLifecycleDataSource = new RoleLifecycleDataSource();       Frames = 0;       while (true)     {         // Get the render job from the queue         CloudQueueMessage jobMsg = jobQueue.Get();           if (jobMsg != null)         {             // Get the file details             string sceneFile = jobMsg.AsString;             string tgaFile = sceneFile.Replace(".pi", ".tga");             string jpgFile = sceneFile.Replace(".pi", ".jpg");               string sceneFilePath = Path.Combine(localStorageRootPath, sceneFile);             string tgaFilePath = Path.Combine(localStorageRootPath, tgaFile);             string jpgFilePath = Path.Combine(localStorageRootPath, jpgFile);               // Copy the scene file to local storage             sceneBlob.DownloadFile(sceneFilePath);               // Run the ray tracer.             string polyrayArguments =                 string.Format("\"{0}\" -o \"{1}\" -a 2", sceneFilePath, tgaFilePath);             Process polyRayProcess = new Process();             polyRayProcess.StartInfo.FileName =                 Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), polyRayPath);             polyRayProcess.StartInfo.Arguments = polyrayArguments;             polyRayProcess.Start();             polyRayProcess.WaitForExit();               // Convert the image             string dtaArguments =                 string.Format(" {0} /FJ /P{1}", tgaFilePath, Path.GetDirectoryName (jpgFilePath));             Process dtaProcess = new Process();             dtaProcess.StartInfo.FileName =                 Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), dtaPath);             dtaProcess.StartInfo.Arguments = dtaArguments;             dtaProcess.Start();             dtaProcess.WaitForExit();               // Upload the image to blob storage             imageBlob.UploadFile(jpgFilePath);               // Add a download job.             downloadQueue.Add(jpgFile);               // Delete the render job message             jobQueue.Delete(jobMsg);               Frames++;         }         else         {             Thread.Sleep(1000);         }           // Log the worker role activity.         roleLifecycleDataSource.Alive             ("CloudRayWorker", RoleLifecycleDataSource.RoleLifecycleId, Frames);     } }     Monitoring Worker Role Instance Lifecycle In order to get more accurate statistics about the lifecycle of the worker role instances used to render the animation data was tracked in an Azure storage table. The following class was used to track the worker role lifecycles in Azure storage.   public class RoleLifecycle : TableServiceEntity {     public string ServerName { get; set; }     public string Status { get; set; }     public DateTime StartTime { get; set; }     public DateTime EndTime { get; set; }     public long SecondsRunning { get; set; }     public DateTime LastActiveTime { get; set; }     public int Frames { get; set; }     public string Comment { get; set; }       public RoleLifecycle()     {     }       public RoleLifecycle(string roleName)     {         PartitionKey = roleName;         RowKey = Utils.GetAscendingRowKey();         Status = "Started";         StartTime = DateTime.UtcNow;         LastActiveTime = StartTime;         EndTime = StartTime;         SecondsRunning = 0;         Frames = 0;     } }     A new instance of this class is created and added to the storage table when the role starts. It is then updated each time the worker renders a frame to record the total number of frames rendered and the total processing time. These statistics are used be the monitoring application to determine the effectiveness of use of resources in the render farm. Rendering the Animation The Azure solution was deployed to Windows Azure with the service configuration set to 16 worker role instances. This allows for the application to be tested in the cloud environment, and the performance of the application determined. When I demo the application at conferences and user groups I often start with 16 instances, and then scale up the application to the full 256 instances. The configuration to run 16 instances is shown below. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="CloudRay" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*">   <Role name="CloudRayWorkerRole">     <Instances count="16" />     <ConfigurationSettings>       <Setting name="DataConnectionString"         value="DefaultEndpointsProtocol=https;AccountName=cloudraydata;AccountKey=..." />     </ConfigurationSettings>   </Role> </ServiceConfiguration>     About six minutes after deploying the application the first worker roles become active and start to render the first frames of the animation. The CloudRay Monitor application displays an icon for each worker role instance, with a number indicating the number of frames that the worker role has rendered. The statistics on the left show the number of active worker roles and statistics about the render process. The render time is the time since the first worker role became active; the CPU time is the total amount of processing time used by all worker role instances to render the frames.   Five minutes after the first worker role became active the last of the 16 worker roles activated. By this time the first seven worker roles had each rendered one frame of the animation.   With 16 worker roles u and running it can be seen that one hour and 45 minutes CPU time has been used to render 32 frames with a render time of just under 10 minutes.     At this rate it would take over 10 hours to render the 2,000 frames of the full animation. In order to complete the animation in under an hour more processing power will be required. Scaling the render farm from 16 instances to 256 instances is easy using the new management portal. The slider is set to 256 instances, and the configuration saved. We do not need to re-deploy the application, and the 16 instances that are up and running will not be affected. Alternatively, the configuration file for the Azure service could be modified to specify 256 instances.   <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="CloudRay" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*">   <Role name="CloudRayWorkerRole">     <Instances count="256" />     <ConfigurationSettings>       <Setting name="DataConnectionString"         value="DefaultEndpointsProtocol=https;AccountName=cloudraydata;AccountKey=..." />     </ConfigurationSettings>   </Role> </ServiceConfiguration>     Six minutes after the new configuration has been applied 75 new worker roles have activated and are processing their first frames.   Five minutes later the full configuration of 256 worker roles is up and running. We can see that the average rate of frame rendering has increased from 3 to 12 frames per minute, and that over 17 hours of CPU time has been utilized in 23 minutes. In this test the time to provision 140 worker roles was about 11 minutes, which works out at about one every five seconds.   We are now half way through the rendering, with 1,000 frames complete. This has utilized just under three days of CPU time in a little over 35 minutes.   The animation is now complete, with 2,000 frames rendered in a little over 52 minutes. The CPU time used by the 256 worker roles is 6 days, 7 hours and 22 minutes with an average frame rate of 38 frames per minute. The rendering of the last 1,000 frames took 16 minutes 27 seconds, which works out at a rendering rate of 60 frames per minute. The frame counts in the server instances indicate that the use of a queue to distribute the workload has been very effective in distributing the load across the 256 worker role instances. The first 16 instances that were deployed first have rendered between 11 and 13 frames each, whilst the 240 instances that were added when the application was scaled have rendered between 6 and 9 frames each.   Completed Animation I’ve uploaded the completed animation to YouTube, a low resolution preview is shown below. Pin Board Animation Created using Windows Kinect and 256 Windows Azure Worker Roles   The animation can be viewed in 1280x720 resolution at the following link: http://www.youtube.com/watch?v=n5jy6bvSxWc Effective Use of Resources According to the CloudRay monitor statistics the animation took 6 days, 7 hours and 22 minutes CPU to render, this works out at 152 hours of compute time, rounded up to the nearest hour. As the usage for the worker role instances are billed for the full hour, it may have been possible to render the animation using fewer than 256 worker roles. When deciding the optimal usage of resources, the time required to provision and start the worker roles must also be considered. In the demo I started with 16 worker roles, and then scaled the application to 256 worker roles. It would have been more optimal to start the application with maybe 200 worker roles, and utilized the full hour that I was being billed for. This would, however, have prevented showing the ease of scalability of the application. The new management portal displays the CPU usage across the worker roles in the deployment. The average CPU usage across all instances is 93.27%, with over 99% used when all the instances are up and running. This shows that the worker role resources are being used very effectively. Grid Computing Scenarios Although I am using this scenario for a hobby project, there are many scenarios where a large amount of compute power is required for a short period of time. Windows Azure provides a great platform for developing these types of grid computing applications, and can work out very cost effective. ·         Windows Azure can provide massive compute power, on demand, in a matter of minutes. ·         The use of queues to manage the load balancing of jobs between role instances is a simple and effective solution. ·         Using a cloud-computing platform like Windows Azure allows proof-of-concept scenarios to be tested and evaluated on a very low budget. ·         No charges for inbound data transfer makes the uploading of large data sets to Windows Azure Storage services cost effective. (Transaction charges still apply.) Tips for using Windows Azure for Grid Computing Scenarios I found the implementation of a render farm using Windows Azure a fairly simple scenario to implement. I was impressed by ease of scalability that Azure provides, and by the short time that the application took to scale from 16 to 256 worker role instances. In this case it was around 13 minutes, in other tests it took between 10 and 20 minutes. The following tips may be useful when implementing a grid computing project in Windows Azure. ·         Using an Azure Storage queue to load-balance the units of work across multiple worker roles is simple and very effective. The design I have used in this scenario could easily scale to many thousands of worker role instances. ·         Windows Azure accounts are typically limited to 20 cores. If you need to use more than this, a call to support and a credit card check will be required. ·         Be aware of how the billing model works. You will be charged for worker role instances for the full clock our in which the instance is deployed. Schedule the workload to start just after the clock hour has started. ·         Monitor the utilization of the resources you are provisioning, ensure that you are not paying for worker roles that are idle. ·         If you are deploying third party applications to worker roles, you may well run into licensing issues. Purchasing software licenses on a per-processor basis when using hundreds of processors for a short time period would not be cost effective. ·         Third party software may also require installation onto the worker roles, which can be accomplished using start-up tasks. Bear in mind that adding a startup task and possible re-boot will add to the time required for the worker role instance to start and activate. An alternative may be to use a prepared VM and use VM roles. ·         Consider using the Windows Azure Autoscaling Application Block (WASABi) to autoscale the worker roles in your application. When using a large number of worker roles, the utilization must be carefully monitored, if the scaling algorithms are not optimal it could get very expensive!

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  • Apache doesn't run multiple requests

    - by Reinderien
    I'm currently running this simple Python CGI script to test rudimentary IPC: #!/usr/bin/python -u import cgi, errno, fcntl, os, os.path, sys, time print("""Content-Type: text/html; charset=utf-8 <!doctype html> <html lang="en"> <head> <meta charset="utf-8" /> <title>IPC test</title> </head> <body> """) ftempname = '/tmp/ipc-messages' master = not os.path.exists(ftempname) if master: fmode = 'w' else: fmode = 'r' print('<p>Opening file</p>') sys.stdout.flush() ftemp = open(ftempname, fmode) print('<p>File opened</p>') if master: print('<p>Operating as master</p>') sys.stdout.flush() for i in range(10): print('<p>' + str(i) + '</p>') sys.stdout.flush() time.sleep(1) ftemp.close() os.remove(ftempname) else: print('<p>Operating as a slave</p>') ftemp.close() print(""" </body> </html>""") The 'server-push' portion works; that is, for the first request, I do see piecewise updates. However, while the first request is being serviced, subsequent requests are not started, only to be started after the first request has finished. Any ideas on why, and how to fix it? Edit: I see the same non-concurrent behaviour with vanilla PHP, running this: <!doctype html> <html lang="en"> <!-- $Id: $--> <head> <meta charset="utf-8" /> <title>IPC test</title> </head> <body> <p> <?php function echofl($str) { echo $str . "</b>\n"; ob_flush(); flush(); } define('tempfn', '/tmp/emailsync'); if (file_exists(tempfn)) $perms = 'r+'; else $perms = 'w'; assert($fsync = fopen(tempfn, $perms)); assert(chmod(tempfn, 0600)); if (!flock($fsync, LOCK_EX | LOCK_NB, $wouldblock)) { assert($wouldblock); $master = false; } else $master = true; if ($master) { echofl('Running as master.'); assert(fwrite($fsync, 'content') != false); assert(sleep(5) == 0); assert(flock($fsync, LOCK_UN)); } else { echofl('Running as slave.'); echofl(fgets($fsync)); } assert(fclose($fsync)); echofl('Done.'); ?> </p> </body> </html>

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  • SSH connection times out

    - by mark
    Given: vm - a WinXPsp3 virtual machine hosted by a Win7sp1 physical machine alice is the user on vm srv - a Win2008R2sp1 server bob is the user on srv quake - a linux server mark is the user on quake Both vm and srv have the same new installation of cygwin (1.7.9) and openssh. Firewall service is disabled on vm (and its host) and on srv All the machines can be pinged from all the machines. ssh mark@quake works OK from both vm and srv. ssh bob@srv works OK from both quake and vm. ssh alice@vm works on the vm itself only, but it fails on the other two machines: alice@vm ~ $ ssh alice@vm alice@vm's password: Last login: Tue Oct 25 23:42:09 2011 from vm.shunra.net [mark@Quake ~]$ ssh -vvv alice@vm OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to vm [172.30.2.60] port 22. debug1: connect to address 172.30.2.60 port 22: Connection timed out ssh: connect to host vm port 22: Connection timed out bob@Srv ~ $ ssh -vvv alice@vm OpenSSH_5.9p1, OpenSSL 0.9.8r 8 Feb 2011 debug1: Reading configuration data /etc/ssh_config debug2: ssh_connect: needpriv 0 debug1: Connecting to vm [172.30.2.60] port 22. debug1: connect to address 172.30.2.60 port 22: Connection timed out ssh: connect to host vm port 22: Connection timed out I used ssh-host-config both on vm and srv to configure the ssh to run as a windows service. Besides that I did nothing else. Can anyone help me troubleshoot this issue? Thank you very much. EDIT The virtual machine software is VMWare Workstation 7.1.4. I think the problem is in its settings, but I have no idea where exactly. The Network Adapter is set to Bridged. EDIT2 All the machines are located in the company lab, I think all of them are on the same segment, but I may be wrong. Below is the ipconfig /all output for each machine (skipping the linux server). I have deleted the Tunnel adapters to keep the output minimal. If anyone thinks they matter, do tell so and I will post them as well. In addition ping output is given to show that DNS is correct. Something else, may be relevant, may be not. Doing psexec to srv works OK, whereas to vm failes with Access Denied. srv: C:\Windows\system32>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : srv Primary Dns Suffix . . . . . . . : shunra.net Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : shunra.net Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Broadcom BCM5709C NetXtreme II GigE (NDIS VBD Client) Physical Address. . . . . . . . . : E4-1F-13-6D-F3-00 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 172.30.6.9(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.248.0 Default Gateway . . . . . . . . . : 172.30.0.254 DNS Servers . . . . . . . . . . . : 172.30.1.1 172.30.1.2 NetBIOS over Tcpip. . . . . . . . : Enabled C:\Windows\system32>ping vm Pinging vm.shunra.net [172.30.2.60] with 32 bytes of data: Reply from 172.30.2.60: bytes=32 time=1ms TTL=128 Reply from 172.30.2.60: bytes=32 time=4ms TTL=128 Reply from 172.30.2.60: bytes=32 time<1ms TTL=128 Reply from 172.30.2.60: bytes=32 time<1ms TTL=128 Ping statistics for 172.30.2.60: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 4ms, Average = 1ms C:\Windows\system32> vm: C:\>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : vm Primary Dns Suffix . . . . . . . : shunra.net Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : shunra.net shunranet Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : shunranet Description . . . . . . . . . . . : VMware Accelerated AMD PCNet Adapter Physical Address. . . . . . . . . : 00-0C-29-8F-A0-0B Dhcp Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IP Address. . . . . . . . . . . . : 172.30.2.60 Subnet Mask . . . . . . . . . . . : 255.255.248.0 Default Gateway . . . . . . . . . : 172.30.0.254 DHCP Server . . . . . . . . . . . : 172.30.1.1 DNS Servers . . . . . . . . . . . : 172.30.1.1 172.30.1.2 Lease Obtained. . . . . . . . . . : Tuesday, October 25, 2011 18:16:34 Lease Expires . . . . . . . . . . : Wednesday, November 02, 2011 18:16:34 C:\>ping srv Pinging srv.shunra.net [172.30.6.9] with 32 bytes of data: Reply from 172.30.6.9: bytes=32 time=1ms TTL=128 Reply from 172.30.6.9: bytes=32 time<1ms TTL=128 Reply from 172.30.6.9: bytes=32 time<1ms TTL=128 Reply from 172.30.6.9: bytes=32 time<1ms TTL=128 Ping statistics for 172.30.6.9: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 1ms, Average = 0ms C:\> vm-host (the host machine of the vm): C:\>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : vm-host Primary Dns Suffix . . . . . . . : shunra.net Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : shunra.net Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Realtek RTL8168D/8111D Family PCI-E Gigabit Ethernet NIC (NDIS 6.20) Physical Address. . . . . . . . . : 6C-F0-49-E7-E9-30 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::f59d:7f6e:1510:6f%10(Preferred) IPv4 Address. . . . . . . . . . . : 172.30.6.7(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.248.0 Default Gateway . . . . . . . . . : 172.30.0.254 DHCPv6 IAID . . . . . . . . . . . : 242020425 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-13-CC-39-80-6C-F0-49-E7-E9-30 DNS Servers . . . . . . . . . . . : 172.30.1.1 194.90.1.5 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter VMware Network Adapter VMnet1: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet1 Physical Address. . . . . . . . . : 00-50-56-C0-00-01 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::cd92:38c0:9a6d:c008%16(Preferred) Autoconfiguration IPv4 Address. . : 169.254.192.8(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.0.0 Default Gateway . . . . . . . . . : DHCPv6 IAID . . . . . . . . . . . : 352342102 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-13-CC-39-80-6C-F0-49-E7-E9-30 DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1 fec0:0:0:ffff::2%1 fec0:0:0:ffff::3%1 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter VMware Network Adapter VMnet8: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet8 Physical Address. . . . . . . . . : 00-50-56-C0-00-08 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::edb9:b78c:a504:593b%17(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.5.1(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : DHCPv6 IAID . . . . . . . . . . . : 369119318 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-13-CC-39-80-6C-F0-49-E7-E9-30 DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1 fec0:0:0:ffff::2%1 fec0:0:0:ffff::3%1 NetBIOS over Tcpip. . . . . . . . : Enabled C:\>ping srv Pinging srv.shunra.net [172.30.6.9] with 32 bytes of data: Reply from 172.30.6.9: bytes=32 time<1ms TTL=128 Reply from 172.30.6.9: bytes=32 time<1ms TTL=128 Reply from 172.30.6.9: bytes=32 time<1ms TTL=128 Reply from 172.30.6.9: bytes=32 time<1ms TTL=128 Ping statistics for 172.30.6.9: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms C:\>ping vm Pinging vm.shunra.net [172.30.2.60] with 32 bytes of data: Reply from 172.30.2.60: bytes=32 time<1ms TTL=128 Reply from 172.30.2.60: bytes=32 time<1ms TTL=128 Reply from 172.30.2.60: bytes=32 time<1ms TTL=128 Reply from 172.30.2.60: bytes=32 time<1ms TTL=128 Ping statistics for 172.30.2.60: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms C:\> EDIT3 I have just checked - the vm-host is able to ssh to the vm machine! I still do not know how to leverage this discovery to solve the problem.

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