Blog Posts from October 2009 (page 1 of 2)

The SOA Manifesto – Pointlessness Manifested

You know what the Agile Manifesto doesn’t have? Video of a “very formal ceremony” announcing said manifesto. Instead, we just have artistically rendered picture of what sure looks like Martin Fowler pointing at a white board while some of the other original signatories look on. Sure, it’s a cool picture, but wouldn’t it have been much cooler if they had captured that moment on video instead? Especially if it was video of them all standing around looking vaguely uncomfortable while photographers took their picture and someone gravely read the manifesto to give it artificially inflated importance.

I only watched ten seconds of the SOA Manifesto announcement video before I realized there’s nothing to see here, move along, just a bunch of navel gazing from the usual SOA suspects.

Seriously, if you having a big announcement about how cool, earth shattering, significant or, hell, even interesting your manifesto is, then it’s not any of those things. It’s a waste of my time.

Then I noticed that my previous manager and personal friend John deVadoss is one of the signatories. I have metric tons of respect for John, so I gave the SOA Manifesto a second chance.

It lost me at the second sentence.

Service orientation is a paradigm that frames what you do. Service-oriented architecture (SOA) is a type of architecture that results from applying service orientation. We have been applying service orientation to help organizations consistently deliver sustainable business value, with increased agility and cost effectiveness, in line with changing business needs.

Are you frakking kidding me? “Service-oriented architecture (SOA) is a type of architecture that results from applying service orientation.” Who the hell came up with that? I didn’t realize the International SOA Symposium had a Department of Redundancy Department.

When you define SOA in terms of SO, then you can’t possibly score well on the practicality quotient.

The rest of the manifesto isn’t much better. What made the Agile manifesto great IMO was that it ran counter to “common” beliefs like “changing requirements late in the process is bad” and “shipping software cycles should take years”. Sure, we all realize how right those Agile manifesto guys were now, but at the time it was the next best thing to heresy for many organizations. Those guys were agents of change. And I mean real change, not “this will help me sell books” change.

SOA manifesto on the other hand is basically repackaged common sense. Stuff like “Recognize that SOA ultimately demands change on many levels” and “The scope of SOA adoption can vary. Keep efforts manageable and within meaningful boundaries” Any help figuring out what that change is or what the scope should be? Nope. Thanks for the advice guys, but I had your so called “Guiding Principles” figured out long ago.

But hey, I’m sure the manifesto will help Thomas Erl et. al. sell more SOA books. So, I guess from that perspective it’s mission accomplished.

IronPython 2.0.3 and 2.6 RC2

It has been a very busy week for the IronPython team. Just under a week ago, we shipped a CTP for .NET Framework 4.0. Since then, we’ve shipped two – yes, two! – more versions of IronPython. Three releases in one week! If we could keep up that pace, we’d be shipping like 27 more releases of IronPython by the end of the year!

FYI, we’re not going to keep up the pace of shipping three releases a week for the next two months. We may be a little crazy on the IronPython team, but we’re not THAT crazy!

Actually, all three of these releases represent fairly small changes in the IronPython source tree. The .NET 4.0 beta was a CTP, so it’s basically whatever we had in our main trunk when they forked .NET Framework for the beta.

IronPython 2.0.3 is a minor point release in the 2.0 branch (duh). In addition to backporting some fixes from 2.6, we had to fix an CLR breaking change in partial trust on Windows 7. If you’re using IronPython 2.0.x in partial trust on Windows 7 you MUST upgrade to 2.0.3 (or 2.6 when it’s released). Sorry about that – but it was out of our hands.

IronPython 2.6 RC2 is – as you would expect – a minor update over the first release candidate. There was a memory leak discovered in the hosting APIs which forced us to do a second release candidate. Since we had to fix that, we took in a few of other fixes including some standard library changes (we left out json by accident in RC1 and Michael Foord got logging updated to work better with IronPython so we took the latest version of it). As per the release notes, we expect this to be the final RC and will re-ship it as RTM in about a month. Please start using this latest release and let us know if you find anything.

Joining Windows

Big news in DevHawk land: I’ll be taking on a new role in the Windows division after I come back from TechEd Europe (plus a week vacation visiting my bro-in-law in Germany after TechEd).

You guys have heard of Windows, right? They just released a new version recently you might be aware of…Actually, I hear it was your idea!

Seriously, I am stoked to be joining the Windows team. I can’t say much about the new job beyond a) it’s in Windows Client (as opposed to Windows Server) and b) I’m working on a team that’s focused on the Windows developer experience. The Windows team is deep in what you might call “building on teh awesome that is Windows 7” but that they simply call “planning”, so sorry if specifics are kinda sparse. I’ll be back working for Mahesh Prakriya, who originally hired me into my current role on the IronPython team. Someday I might tell you the Mahesh PyCon Lego Story, but for now I’ll just say I was great working for Mahesh the first time and I think this time is going to be even better.

Working on Windows…focused on developer experience…for Mahesh – It’s like the perfect storm of work geekdom for me.

Of course, starting a new job means my time on the IronPython team is coming to an end. As excited as I am about this new opportunity in the Windows division, I’m a little sad to be leaving Developer Division and the IronPython team. I’ve joked with audiences that I care about Python because Microsoft pays me to care about Python, but that’s not completely true. Python is a fantastic language and IronPython’s combination of Python + .NET is hard to beat in my opinion. IronPython has made significant progress while I’ve been here the last eighteen months – two major releases (well, 2.6 is almost done), redisting the Python standard library, Visual Studio 2010 compat – but there’s still much for IronPython to accomplish. And of course, leaving behind such great teammates like Dino, Dave, Jim and Jimmy is ALWAYS hard.

The Windows team is somewhat tighter lipped than the totally transparent approach we use in IronPython. Not to worry, my evangelism skills were part of the reason I got the job so you’ll be hearing plenty from me soon enough. However, my posting here will be kinda sparse until I get my bearings over there. Until then, I’m sure that you will be absolutely fascinated by non-work-related-but-still-sometimes-geeky minutia I post on Twitter.

IronPython and IronRuby CTPs for .NET 4.0 Beta 2

In case you’ve been hiding under a rock (or maybe just aren’t tracking developments in the .NET community outside of IronPython), Microsoft released Visual Studio 2010 beta 2 this week. Of course for me personally, the most important feature in Visual Studio 2010 is C# 4.0 new dynamic type (also available in Visual Basic, but since VB already supported some level of late binding it’s not exactly “new” to VB).

For those of you who want to experiment with this cool new feature, may I present IronPython 2.6 CTP for .NET 4.0 Beta 2. If you can’t think of any cool things to try with this new feature, the VB team blog has some scenarios to get your started.

Also available: IronRuby CTP for .NET 4.0 Beta 2 if you’re more into gemstones than snakes.

These are preview releases, which means they’ve gone thru basic testing. If you find any bugs, PLEASE report them via the usual channel. I wrote in my Post 2.6 Roadmap post, “we are committed to shipping the RTM of our .NET 4.0 version the day that Visual Studio 2010 is publicly available” but that means shaking out the bugs between now and then. We need your help so we’re ready to go by Visual Studio 2010 launch – March 22, 2010 as per Soma’s blog.

BTW, Alcides Fonseca suggested we call this release “IronPython 2.6 N4” since it’s designed to run on .NET Framework 4.0. I like that. What do you think?

Hybrid App Debugging – The Debug Window

In my last installment, I added support for a separate debug window on a separate thread from the main window thread. That way, I can pause the execution of the main window while the debug window stays responsive to user input. Now, let’s add some functionality to the debug window. I’m going to start by showing the source code of the python file being executed.

private void OnTraceback(TraceBackFrame frame, string result, object payload)
    FunctionCode code = (FunctionCode)frame.f_code;
    if (_curCode == null || _curCode.co_filename != code.co_filename)
        foreach (var line in System.IO.File.ReadAllLines(code.co_filename))
            _source.Inlines.Add(new Run(line + "rn"));

The TraceBackFrame instance has a property f_code that represents the FunctionCode object being executed in this frame. We have to explicitly cast to FunctionCode type because currently we’re exposing all properties that hang off TraceBackFrame as object type. Since Python is a dynamic language, we’re going to use reflection against the instance itself anyway so it doesn’t really matter what the return type is. However, I’ve asked Dino to change the TraceBackFrame type to use explicit types in order to make it easier to use SetTrace from statically typed languages like C#. Look for that in RC2.

After we cast the code object so it can be used from C#, we check to see if the currently loaded file matches the file currently loaded into the UI. I’ve ranted recently about the limitations of WPF’s TextBox but I didn’t want to get hung up syntax highlighting for this sample so I just went ahead and used the RichTextBox. In the DebugWindow Loaded event handler, I create _source as a WPF Paragraph and then wrap it in a FlowDocument and use it as the RichTextBox’s Document. I set the FlowDocument to be extremely wide, so as to avoid word wrapping. Then when I need to load a new source file, I clear _source of it’s current contents and add a single line run for every line of code in the file. This convention becomes useful later when I go to highlight the current line of code.

Once I load the current file, I save the current frame, code, result and payload in instance fields and then switch on result to determine what to do next. Currently, I’m just highlighting the relevant line of code and setting a TextBlock control in the menu bar.

private void TracebackCall()
    dbgStatus.Text = string.Format("Call {0}", _curCode.co_name);
        Brushes.LightGreen, Brushes.Black);

private void TracebackReturn()
    dbgStatus.Text = string.Format("Return {0}", _curCode.co_name);
        Brushes.LightPink, Brushes.Black);

private void TracebackLine()
    dbgStatus.Text = string.Format("Line {0}", _curFrame.f_lineno);
        Brushes.Yellow, Brushes.Black);

In Visual Studio, we typically highlight the current line of code in yellow. However, that doesn’t work as great in a language like Python that delineates code blocks with whitespace. In ipydbg, I indicated function return with three carets. But I didn’t want to be modifying the text in the RichTextBox here so instead I used different colors for the different traceback event types: light green for call, light pink for return and yellow for line. The frame object contains the current line number, which I use for call and line, while the code object has the first line of the current code object, which I use for return. HighlightLine highlights the line in question with the colors provided and also scrolls that line into view if it isn’t already visible.

So now when a traceback is handled, it shows the text for the file being executed and highlights the appropriate line, based on the type of traceback event that happened. Now all we need is to have some way be able to continue execution. In the code, you’ll see I’ve defined a series of RoutedUICommands for common debugger commands. I’ve got the StepIn command wired up in the DebugWindow XAML to a menu item and the “S” keystroke. All that remains is to define StepInExecuted.

private void StepInExecuted(object sender, ExecutedRoutedEventArgs e)
    dbgStatus.Text = "Running";

    foreach (var i in _source.Inlines)
        i.Background = rtbSource.Background;
        i.Foreground = rtbSource.Foreground;


This function does three basic things: changes the dbgStatus text, resets all the text in the RichTextBox back to the default coloring, and sets the _dbgContinue AutoResetEvent which signals the main window thread that’s been blocked in OnTracebackReceived to continue.

With this post, I’m about even with the code that’s up on GitHub. That code has a few other capabilities – notably it will stop tracing if you close the debug window and it supports StepOut command which disables traceback for the current scope by returning null in OnTracebackReceived. But I haven’t implemented things like:

  • Set Next Statement
  • Viewing and changing variables
  • Debugger REPL
  • Breakpoint Management

Any suggestions on which of those would you like to see next?