Techie Head

I've been a fan of Application Insights for quite some time now, it's helped debug and resolve problems that we didn't even know we had! In the new tiers in Azure, the free tier gets 5 million data points a month. That sounds like a lot, until you get a message 10 days into the month warning that you've already used 80% of the limit. Our problem was that it tracks a whole heap of requests to things we don't care about. For example, requests for images, some AJAX requests for social media sharing links and our custom health probe (used by Azure load balancing to decide whether to route requests) were taking up a big portion of that data allowance. I opened up Bing and Googled whether I could exclude some urls - that led me to this Stack Overflow question: http://stackoverflow.com/questions/31149720/is-it-possible-to-exclude-a-url-from-application-insights It looked sensible enough. I first upgraded all of my Application Insights NuGet packages to the latest ver...

I just had a problem that has taken ages to solve so blogging on the off chance it helps someone in need (or possibly future me). When this happens you need to check that you don't have a dodgy instance lying around on your localdb. All of the stuff I read online pointed at the storage emulator using (localdb)\v11.0 but I couldn't see anything in there when I checked. I decided to do a bit more digging: Running sqllocaldb i lists the instances on my localdb... I connected to MSSQLLocalDB with Visual Studio's Sql Server Object Explorer (Sql Server Management Studio would work just as well) And deleted the AzureStorageEmulatorDb* entries. The next time I started to storage emulator it all worked fine!

Froala was very straightforward to get up and running. Their documentation is pretty good but lacks an English version of the server integration for image/file uploads. Ignoring the paste, here's a view of the simple upload of images/files. I have added a parameter to the method called location which lets me have the editor save files to different places depending on where the editor is. [HttpPost] [Route( "content/uploadfile" )] public ActionResult UploadFile( string location, HttpPostedFileBase file) { string fileName; try { // resourceService handles resizing image and saving to Azure blob storage. fileName = resourceService.AddFileInLocation(location, file); } catch (Exception ex) { return Json2( new { error = ex.Message }); } // /resources/ proxies requests to assets var data = new { link = ( "/resources/" + location + "/" + fileName).ToLower() }; return Json2(d...

When needing to add a bit of WYSIWYG into a web application I've always gone with the stalwart TinyMCE. It does the job, it's configurable with regards to what you allow in your elements and generally users use it without too much trouble. We just had a few issues that were annoying with TinyMCE so we went on a hunt for a new editor to use in its place. A colleague recommended Froala  as he had recently evaluated it for another project. We use angular extensively (and had to write a directive for TinyMCE integration) so I was expecting to have to do the same for Froala. Not so! They already have a directive for angular available on GitHub . It took approximately 5 minutes to go from TinyMCE to basic Froala. It took another day or so to get all the functionality we wanted - that includes creating APIs for image and file upload. Things I really like about Froala: Good documentation It seems to produce better html than TinyMCE did (fewer random <p> tags!) Pastin...

Today I messed up. I'm a strong believer in sharing experiences of failure. If no one talks about the times they make mistakes, we're going to be doomed to repeat the same errors over and over again. So, here goes... Today I made a big mistake in a production application that resulted in 15 minutes of frantic database scripting and partial service interruption. I'm going to share what I did wrong, in part so that I focus on what I can do better next time but also because I don't want other people to make the same mistakes. Here's what happened. In our application we have some entities which use a natural key rather than a database generated primary key. This can make life easier when querying as you reduce the number of joins but still have referential integrity (with the cost of a bit of denormalisation). In the past, the whole DAL was hand coded SQL so it saved a considerable amount of developer time; we now use an ORM so we really don't care about the ...

In our application we have multiple web front ends communicating with one or more worker roles. This allows our worker roles to take the brunt of expensive operations. For example, some (very infrequent) actions require up to about 500 emails being sent (via Amazon SES). Before Azure (BA), we did everything on the web server - it wasn't common but sometimes users reported over a minute from clicking the button to the result being displayed. Our move to using workers responding to queue messages has massively sped this sort of thing up. Most actions on the worker are triggered by queue messages but we do have several things that just need to happen at set intervals (we use blob leases to prevent multiple workers doing the same thing). While implementing the "ExclusiveJobHost" and "BlobLease" classes, I noticed a common pattern that I ended up pulling out: public class RecurringAction { private ManualResetEvent exitSignal = new ManualResetEvent( false ...

Microsoft Azure Table storage is a very flexible No-Sql store for structured data. Each entity in the table is uniquely identified by a partition key and a row key. A good choice of these is beyond the scope of this post. However, it can be useful to check that entity you want to add to the table has valid partition and row keys. Here's a simple class that encapsulates those rules: /// <summary> /// Encapsulates knowledge about valid values for keys in Microsoft Azure table storage. /// </summary> /// <remarks> /// Rules are found here http://msdn.microsoft.com/library/azure/dd179338.aspx /// </remarks> internal static class KeyValidator { /// <summary> /// Determines whether the specified key is valid. /// </summary> /// <param name="keyValue">The key.</param> /// <param name="errors">Any errors in the value supplied.</param> /// <returns><c>tru...