sn.printf.net

Since I started working as a programmer, I’ve always taken notes in meetings, and jotted things down during the day to remember, but these were all usually on an A4 notepad, which I’ve always used as a daily scratch pad, and until recently I have never kept a proper journal which I could refer back to at a later time.

A colleague of mine with whom I have been working on a project together, has for a long time kept a development journal, or diary, of things that have happened in his work day. Examples are:

• Meeting notes, who was present, salient points of what was said and what was agreed
• Design ideas, diagrams, pseudo code
• Technical notes on gotchas in the language and application
• Noteworthy events connected to the project

The event which got me interested in his note keeping was one day when the Produce Owner made a decision about the scope and importance of a particular feature. The colleague in question looked back over his notes and was able to prove that the PO had made a different decision about the same thing a few weeks before. When things like this happened a few more times, I really sat up and started to ask some questions.

“If it isn’t written down, it didn’t happen”, was the response.

If you write it down, you are more likely to remember it. There is a large body of evidence that suggests that the simple act of physically writing notes helps aid memory retention. There are a lot of articles and blogs about this subject, but I’d never paid it much attention. After all, I’d kept enough notes when at school and university, and I didn’t think I need to when I was working.

I could not have been more wrong.

So I started taking notes. I got an A4 lined hardback notebook and started writing stuff down.

And: It works.

So for example, I can tell you who made the decision in a meeting thirteen months ago which meant a feature in the application was developed in a particular way which now makes it upsettingly difficult to modify that part of the application. I can produce my design notes from six months ago where I planned the refactoring of some functionality, and the implications of said work, and which developers on the project I’d talked it through with to get some sanity checking that what I was proposing wasn’t stupid. I can tell you who brought cakes in on a particular day last month and who said which particular funny thing last week that is now part of the project slang.

What I’ve found is that if you write stuff down during the day, about what you are doing, it helps you remember (like the research says it will), and makes you think about what you have done already, and what you need to do in the future. This is all stuff that is required for a Scrum stand-up, if you have to do those. It also provides amunition for those of you who have to suffer through the dreaded annual performance appraisal; or, helps remind you what to list on the invoice when billing for the hours you’ve worked.

Lastly, it helps (me, anyway) remember what I was doing on my latest pet project that I haven’t touched for eight months. Which I should get back to.

As clever geeks we are sort of protected form the ‘big bad world’ by living in expenses cities and suburbs, working with other geeks and getting paid well.

In prison I guess that counts for nothing.

¯\_(ツ)_/¯ I guess!! 

Make a public connection private (source):

Set-NetConnectionProfile -InterfaceAlias <interface name> -NetworkCategory Private

Rename the adapter (source):

Get-NetAdapter -Name Ethernet | Rename-NetAdapter -NewName Renamed

I’m posting this so I can find it again next time I forget

For anyone keeping score, I haven’t updated my blog for over a year.

Insert excuses here

I know that I should do, Hanselman and Somnez both recommend it.

Anyway, I’ve come up with some goals for myself for the next year:

• Get on Hanselminutes
  • Failing that, any other developer focused podcast will do
• Blog more regularly
• Contribute more to open source
• Release an open source project of my own
• Become rich and famous

So we shall see what happens.

I like this talk a lot: what modularity is, what we use it for, how modularity happens in systems, and how we can use modularity to manage change.

Last night I found out i’d lost a friend, and if you’ll be patient with my words, I’d like to reflect a little.

Mathie was one of the older, weirder, geeks I met. I’d escaped my home town in the edge of nowhere, and it was my first time having a peer group of adults.

He’d helped everywhere. With the student run shell server, with the local IRC server everyone collected on, a known and friendly face on the circuit

Mathie was one of the many people behind Scottish Ruby Conference, responsible for bringing a lot of interesting people into Edinburgh, and into my life.

Why wasn’t this talk given at Scottish Ruby Conference

I fucked up

In front of everyone assembled at the fringe track, a collection of talks that didn’t quite make it, mathie answered honestly. It’s kinda how i’ll remember him: a bit of a fuckup.

A fuckup who, changed my life for the better.

Thanks mathie, I hope to pass on some of your kindness.

RIP, You fucking idiot.

This week I gave a short talk on a paper I love: End-to-End Arguments in System Design

The talk was recorded and uploaded (but not captioned), and you can watch it here: https://skillsmatter.com/skillscasts/8200-end-to-end-arguments-in-system-design-by-saltzer-reed-and-clark

(Writing this down so I can google it when I inevitably forget about it in the future)

Powershell supports Unicode in a custom prompt, but if it’s coming out garbled, then you probably forgot to save your profile.ps1 as UTF-8 WITH BOM.

This is UTF-8 (no BOM):

This is is UTF-8 w/ BOM:

Nice.

(BTW, the code for this custom prompt is here)

The principle of YAGNI should always apply, and I was recently reminded of that when I had to build a small application to give to a user for a small one off task. We’re talking a single screen application with a single button on it. Idiot proof.

So, File > New > Winforms application - doesn’t have to be anything fancy. Then I caught myself: My first instinct was to add StructureMap to it.

I thought to myself that it’s only going to have a few classes, I mean just because it’s a small winforms app doesn’t mean I’m going to shit up the code behind with business logic and data access, so why bother with the overhead of adding a IOC library?

It doesn’t mean I don’t have to use dependency injection. Mark Seemann calls this “Poor Man’s DI”.

    static class Program
    {
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            var service = new Service(new Database(), new Other());
            Application.Run(new Main(service));
        }
    }

It’s short and sweet, and there is no IOC container configuration to worry about. Because I don’t need to.

What about when….

Requirements change. “Can it just do this as well…?” More dependencies required, perhaps another form, maybe another service or two. I think I’d see how far I could push Poor Man’s DI before I brought in a proper IOC container to help manage things.

Configuring SignalR in ASP.NET MVC, using StructureMap as the IoC container is fairly straightforward, but not without some subtleties that caught me out.

For the purposes of this post, I’m going to assume that you are familiar with both SignalR and StructureMap, and that you know how to configure them in an ASP.NET MVC application. I will also assume that through some google-fu you have seen the Dependency Injection in SignalR guidance, and have worked through it and got to the “Using IoC Containers in SignalR” section.

I would assume, although I’ve not tested it, that much of this could also be applied to a self-hosted SignalR server.

Library versions used

This post is based on:

• Asp.Net MVC 5.2.3
• SignalR 2.2.0
• StructureMap 3.1.5.154
• StructureMap.MVC5 3.1.1.134

Follow the guidance up to the section on using Ninject, at which point we now want to configure StructureMap.

Replace the SignalR Dependency Resolver

The implementation is nearly identical, with some obvious StructureMap specific differences:

public class StructureMapSignalRDependencyResolver : DefaultDependencyResolver
{
    private readonly IContainer _container;
    
    public StructureMapSignalRDependencyResolver(IContainer container)
    {
   	    _container = container;
    }
    
    public override object GetService(Type serviceType)
    {
   	    return _container.TryGetInstance(serviceType) ?? base.GetService(serviceType);
    }
    
    public override IEnumerable<object> GetServices(Type serviceType)
    {
   	    var objects = _container.GetAllInstances(serviceType).Cast<object>();
   	    return objects.Concat(base.GetServices(serviceType));
    }
}

The behaviour is fairly similar. TryGetInstance will attempt to resolve the type, and if it doesn’t know about it, will return null, in which case we call the base resolver, which does.

Register this with StructureMap:

For<IDependencyResolver>().Singleton().Use<StructureMapSignalRDependencyResolver>();

In your Startup, where you configure SignalR, we need to use this new resolver implementation:

var resolver = DependencyResolver.Current.GetService<Microsoft.AspNet.SignalR.IDependencyResolver>();

var hubConfiguration = new HubConfiguration
{
    Resolver = resolver

/* other options as required */
};

Here, we are using the MVC DependencyResolver, which has already been replaced by StructureMap thanks to StructureMap.MVC5, to resolve an instance of the SignalR dependency resolver we’ve registered, which we then tell SignalR to use with a hub configuration object.

Now we just need to configure the StructureMap registry, and teach it how to resolve IHubConnectionContext<dynamic>:

For<IConnectionManager>().Use<ConnectionManager>();
For<IStockTicker>()
    .Singleton()
    .Use<StockTicker>()
    .Ctor<IHubConnectionContext<dynamic>>()
    .Is(ctx => ctx.GetInstance<IDependencyResolver>()
        .Resolve<IConnectionManager>()
        .GetHubContext<StockTickerHub>().Clients);

As in the guidance, we want the StockTicker instance to be a singleton, and we have specify how to resolve the IHubConnectionContext<dynamic> which the StockTicker requires. In the Is, I’m using the context to resolve the default SignalR connection manager we’ve registered. This isn’t in the guidance, but I couldn’t get it work without doing this.

If anyone has comments/improvements on this, I’d love to hear them.

Your app’s GUID doesn’t match the GUID in the store. You have to take the published app guid from your store listing info (ie the one in the url for your app) and update your project files with this GUID.

For WP8.0 (Silverlight): WMAppManifest.xml

For WP8.1/Universal Apps: Package.appxmanifest

I found the solution for WP8.0 here, and the solution also works for Universal Apps. The problem manifests itself as a mysterious exception when calling “CurrentApp.RequestProductPurchaseAsync” or “CurrentApp.LoadListingInformationAsync”. Very frustrating.

Lock’n'Roll, a Pidgin plugin for Windows designed to set an away status message when the PC is locked, has received its first update in three and a half years!

Daniel Laberge has forked the project and released a version 1.2 update which allows you to specify which status should be set when the workstation locks. Get it while it’s awesome (always)!

terVec3 lb = ti->points[1] - ti->points[0];
terVec3 lc = ti->points[2] - ti->points[0];
terVec2 lbt = ti->texCoords[1] - ti->texCoords[0];
terVec2 lct = ti->texCoords[2] - ti->texCoords[0];

// Generate local space for the triangle plane
terVec3 localX = lb.Normalize2();
terVec3 localZ = lb.Cross(lc).Normalize2();
terVec3 localY = localX.Cross(localZ).Normalize2();

// Determine X/Y vectors in local space
float plbx = lb.DotProduct(localX);
terVec2 plc = terVec2(lc.DotProduct(localX), lc.DotProduct(localY));

terVec2 tsvS, tsvT;

tsvS[0] = lbt[0] / plbx;
tsvS[1] = (lct[0] - tsvS[0]*plc[0]) / plc[1];
tsvT[0] = lbt[1] / plbx;
tsvT[1] = (lct[1] - tsvT[0]*plc[0]) / plc[1];

ti->svec = (localX*tsvS[0] + localY*tsvS[1]).Normalize2();
ti->tvec = (localX*tsvT[0] + localY*tsvT[1]).Normalize2();

#define SH_AMBIENT_FACTOR   (0.25f)
#define SH_LINEAR_FACTOR    (0.5f)
#define SH_QUADRATIC_FACTOR (0.3125f)

void LambertDiffuseToSHCoefs(const terVec3 &dir, float out[9])
{
  // Constant
  out[0] = 1.0f * SH_AMBIENT_FACTOR;

  // Linear
  out[1] = dir[1] * SH_LINEAR_FACTOR;
  out[2] = dir[2] * SH_LINEAR_FACTOR;
  out[3] = dir[0] * SH_LINEAR_FACTOR;

  // Quadratics
  out[4] = ( dir[0]*dir[1] ) * 3.0f*SH_QUADRATIC_FACTOR;
  out[5] = ( dir[1]*dir[2] ) * 3.0f*SH_QUADRATIC_FACTOR;
  out[6] = ( 1.5f*( dir[2]*dir[2] ) - 0.5f ) * SH_QUADRATIC_FACTOR;
  out[7] = ( dir[0]*dir[2] ) * 3.0f*SH_QUADRATIC_FACTOR;
  out[8] = 0.5f*( dir[0]*dir[0] - dir[1]*dir[1] ) * 3.0f*SH_QUADRATIC_FACTOR;
}


void RotateCoefsByMatrix(float outCoefs[9], const float pIn[9], const terMat3x3 &rMat)
{
  // DC
  outCoefs[0] = pIn[0];

  // Linear
  outCoefs[1] = rMat[1][0]*pIn[3] + rMat[1][1]*pIn[1] + rMat[1][2]*pIn[2];
  outCoefs[2] = rMat[2][0]*pIn[3] + rMat[2][1]*pIn[1] + rMat[2][2]*pIn[2];
  outCoefs[3] = rMat[0][0]*pIn[3] + rMat[0][1]*pIn[1] + rMat[0][2]*pIn[2];

  // Quadratics
  outCoefs[4] = (
        ( rMat[0][0]*rMat[1][1] + rMat[0][1]*rMat[1][0] ) * ( pIn[4] )
      + ( rMat[0][1]*rMat[1][2] + rMat[0][2]*rMat[1][1] ) * ( pIn[5] )
      + ( rMat[0][2]*rMat[1][0] + rMat[0][0]*rMat[1][2] ) * ( pIn[7] )
      + ( rMat[0][0]*rMat[1][0] ) * ( pIn[8] )
      + ( rMat[0][1]*rMat[1][1] ) * ( -pIn[8] )
      + ( rMat[0][2]*rMat[1][2] ) * ( 3.0f*pIn[6] )
      );

  outCoefs[5] =  (
         ( rMat[1][0]*rMat[2][1] + rMat[1][1]*rMat[2][0] ) * ( pIn[4] )
       + ( rMat[1][1]*rMat[2][2] + rMat[1][2]*rMat[2][1] ) * ( pIn[5] )
       + ( rMat[1][2]*rMat[2][0] + rMat[1][0]*rMat[2][2] ) * ( pIn[7] )
       + ( rMat[1][0]*rMat[2][0] ) * ( pIn[8] )
       + ( rMat[1][1]*rMat[2][1] ) * ( -pIn[8] )
       + ( rMat[1][2]*rMat[2][2] ) * ( 3.0f*pIn[6] )
       );

  outCoefs[6] = (
              ( rMat[2][1]*rMat[2][0] ) * ( pIn[4] )
       +      ( rMat[2][2]*rMat[2][1] ) * ( pIn[5] )
       +      ( rMat[2][0]*rMat[2][2] ) * ( pIn[7] )
       + 0.5f*( rMat[2][0]*rMat[2][0] ) * ( pIn[8])
       + 0.5f*( rMat[2][1]*rMat[2][1] ) * ( -pIn[8])
       + 1.5f*( rMat[2][2]*rMat[2][2] ) * ( pIn[6] )
       - 0.5f * ( pIn[6] )
          );

  outCoefs[7] =  (
         ( rMat[0][0]*rMat[2][1] + rMat[0][1]*rMat[2][0] ) * ( pIn[4] )
       + ( rMat[0][1]*rMat[2][2] + rMat[0][2]*rMat[2][1] ) * ( pIn[5] )
       + ( rMat[0][2]*rMat[2][0] + rMat[0][0]*rMat[2][2] ) * ( pIn[7] )
       + ( rMat[0][0]*rMat[2][0] ) * ( pIn[8] )
       + ( rMat[0][1]*rMat[2][1] ) * ( -pIn[8] )
       + ( rMat[0][2]*rMat[2][2] ) * ( 3.0f*pIn[6] )
       );

  outCoefs[8] = (
              ( rMat[0][1]*rMat[0][0] - rMat[1][1]*rMat[1][0] ) * ( pIn[4] )
        +     ( rMat[0][2]*rMat[0][1] - rMat[1][2]*rMat[1][1] ) * ( pIn[5] )
        +     ( rMat[0][0]*rMat[0][2] - rMat[1][0]*rMat[1][2] ) * ( pIn[7] )
        +0.5f*( rMat[0][0]*rMat[0][0] - rMat[1][0]*rMat[1][0] ) * ( pIn[8] )
        +0.5f*( rMat[0][1]*rMat[0][1] - rMat[1][1]*rMat[1][1] ) * ( -pIn[8] )
        +0.5f*( rMat[0][2]*rMat[0][2] - rMat[1][2]*rMat[1][2] ) * ( 3.0f*pIn[6] )
         );
}

float3 SampleSHQuadratic(float3 dir, float3 shVector[9])
{
  float3 ds1 = dir.xyz*dir.xyz;
  float3 ds2 = dir*dir.yzx;    // xy, zy, xz

  float3 v = shVector[0];

  v += dir.y * shVector[1];
  v += dir.z * shVector[2];
  v += dir.x * shVector[3];

  v += ds2.x * shVector[4];
  v += ds2.y * shVector[5];
  v += (ds1.z * 1.5 - 0.5) * shVector[6];
  v += ds2.z * shVector[7];
  v += (ds1.x - ds1.y) * 0.5 * shVector[8];

  return v;
}

void SHForDirection(const terVec3 &dir, float out[9])
{
  // Constant
  out[0] = 1.0f;

  // Linear
  out[1] = dir[1] * 3.0f;
  out[2] = dir[2] * 3.0f;
  out[3] = dir[0] * 3.0f;

  // Quadratics
  out[4] = ( dir[0]*dir[1] ) * 15.0f;
  out[5] = ( dir[1]*dir[2] ) * 15.0f;
  out[6] = ( 1.5f*( dir[2]*dir[2] ) - 0.5f ) * 5.0f;
  out[7] = ( dir[0]*dir[2] ) * 15.0f;
  out[8] = 0.5f*( dir[0]*dir[0] - dir[1]*dir[1] ) * 15.0f;
}

terVec3 RandomDirection(int (*randomFunc)(), int randMax)
{
   float u = (((float)randomFunc()) / (float)(randMax - 1))*2.0f - 1.0f;
   float n = sqrtf(1.0f - u*u);

   float theta = 2.0f * M_PI * (((float)randomFunc()) / (float)(randMax));

   return terVec3(n * cos(theta), n * sin(theta), u);
}

The Problem

For those using chef to automate your server infrastructure you probably find managing third-party cookbooks to be a pain. Ideally I want to make custom changes to a cookbook while still being able to track for upstream enhancements.

A few techniques I see being used are:

no tracking: Manually download an archive from github or opscode community and drop it in your cookbooks/ directory. Easy to make custom changes but you have no automated way to check for updates.

git submodules: This tracks upstream well, but unless you own the repo you can’t make changes.

fork it: Since pretty much all cookbooks reside on github, so you can fork a copy. This works, but now you might have dozens of different repos to manage. And checking for updates means going into each repo and manually merging in enhancements from the upstream.

knife vendor: Now we are getting somewhere. Chef’s knife command has functionality for dealing with third-party cookbooks. It looks something like this:

knife cookbook site vendor nginx

This downloads the nginx cookbook from the opscode community site, puts an unmodified copy in a chef-vendor-nginx git branch, and then puts a copy in your cookbooks/nginx dir in your master branch. When you run the install again it will download the updated version into the chef-vendor-nginx branch, and then merge that into master.

This is a good start, but it has a number of problems. First you are restricted to using what is available on the opscode community site. Second, although this seems like a git-centric model, knife is actually downloading a .tar.gz file. In fact if you visited the nginx cookbook page you would see it only offers an archive download, no way to inspect what this cookbook actually provides before installing.

There is a sea of great high-quality cookbooks on github. Since we all know and love git it would be great if we could get the previous functionality but using git repositories as a source instead.

A Solution

Enter knife-github-cookbooks. This gem enhances the knife command and lets us get the above functionality by pulling from github rather than downloading from opscode. To use it just install the gem and run:

knife cookbook github install cookbooks/nginx

By default it assumes a username/repo from github. So for each cookbook you install you will have a chef-vendor-cookbookname branch storing the upstream copy and a cookbooks/cookbook-name directory in your master branch to make local changes to.

If you want to check for upstream changes:

knife cookbook github compare nginx

That will launch a github compare view. You can even pass this command a different user who has forked the repo and see or merge in changes from that fork! Read more about it on the github page.

One thing to keep in mind is this gem doesn’t pull in required dependencies automatically, so you will have to make sure you download any requirements a cookbook might have. You can check what dependencies a cookbook requires by inspecting the metadata files.

Bonus Tip!

Opscode has a github repository full of recipes you probably want to use (opscode/cookbooks). Unfortunately using this repository would mean pulling in *all* of those cookbooks. That just clutters up your chef project with cookbooks you don’t need. Luckily there is https://github.com/cookbooks! This repository get updated daily and separates each opscode/cookbook cookbook into a separate git repository.

Now you can cherry-pick the cookbooks you want, and manage them with knife-github-cookbooks!

Make sure you have the same path to the binaries you want to profile on your target device as your workstation.

On your profiling target as root:

export KREXP=dpkg -L kernel-debug | grep "vmlinux-2.6"
opcontrol --init
opcontrol --vmlinux=$KREXP
opcontrol --separate=kernel
opcontrol --status
opcontrol -c=8

start your application

as root again:

opcontrol --stop;  opcontrol --reset; opcontrol --start; sleep 5; opcontrol --stop

rm -rf /var/lib/oprofile && scp -r root@192.168.2.15:/var/lib/oprofile /var/lib/
this should give you some log info:
opreport -l -r

opreport -c /path/to/binary_to_profile > /tmp/opreport.txt
oprofile-callgraph-to-svg -e 1 -n 1 /tmp/opreport.txt

for(nsIntRegionRectIterator iter(mUpdateRegion); const nsIntRect* R=iter.Next();)
//do something with R