The art of simplicity

After switching from PhantomJs to Chrome in headless mode for our Angular tests, our tests started to behave flaky with sometimes success and sometimes failure. When the tests failed, we saw the following error message in the logs: [32m28 08 2018 10:41:44.851:INFO [HeadlessChrome 68.0.3440 (Windows 7.0.0)]: [39mConnected on socket W4CI4bKonF845CKZAAAA with id 22875346 2018-08-28T08:41:54.8669569Z [33m28 08 2018 10:41:54.860:WARN [HeadlessChrome 68.0.3440 (Windows 7.0.0)]: [39mDisconnected (1 times), because no message in 10000 ms. 2018-08-28T08:41:54.8864889Z HeadlessChrome 68.0.3440 (Windows 7.0.0) ERROR 2018-08-28T08:41:54.8864889Z   Disconnected, because no message in 10000 ms. 2018-08-28T08:41:54.8874655Z HeadlessChrome 68.0.3440 (Windows 7.0.0) ERROR 2018-08-28T08:41:54.8874655Z   Disconnected, because no message in 10000 ms. 2018-08-28T08:41:54.8874655Z To fix it, we changed the default Karma settings to a more fault tolerant con...

One of the developers in my team complained that one of the ASP.NET Web API requests was really slow and asked me to investigate the performance issue. When I opened the solution I saw the following code: Do you notice what’s wrong? The problem is that inside the validator an async call is done where if you look at the controller the validator is invoked in a synchronous way. This causes the API to hang as ASP.NET keeps waiting for a result that is never returned. The solution was simple; just switch to the ValidateAsync method and await the result in the controller:

If you used the Angular CLI to create your Angular project, there is not that much work left to do to start using Chrome in headless mode to run your end-to-end tests. Let’s walk through the steps: Open the protractor.conf.js file in the e2e folder. Change the capabilities entry in the config to include a chromeOptions object like this: capabilities: {   chromeOptions: {     args: [ "--headless" ]   },   'browserName': 'chrome' }, By using the args property, we pas a --headless option. This configures Chrome to run in headless mode. That is all we need to do . Just kick off your E2E tests using: npm run e2e

After changing our ASP.NET Core application to no longer run under the root site(e.g. https://localhost/ ) but under a virtual directory instead (e.g. https://localhost/mysampleapp/ ) , loading the API definitions in Swagger no longer worked and failed with the following error message: Fetch error undefined swagger/v1/swagger.json To fix the problem, I had to do 2 things: First I updated the Swagger json generation to set the SwaggerDoc to a specific path. Although the documentation mentions the first parameter of SwaggerDoc as the name, it becomes part of the URI of your swagger.json file. In this case I set the name to ‘v1’: As a second step, I had to update the Swagger UI configuration to generate the swagger endpoint on a relative path. Important here is that the name of the swagger doc matches part of the URI before the swagger.json; in our case ../swagger/ v1 /swagger.json

Last week we lost a lot of time investigating an issue with ‘ion-menu’ , one of the built-in controls of Ionic. The problem was that once the menu was opened it would no longer refresh it’s data. What we do is showing some user data on the top of the menu, this data is returned with an http call from the server and updated through an observable subscription. However pushing a new value on the observable had no effect on the view although the component data was in fact updated. As a workaround we used the built-in event bus to publish an event once the user was loaded. We handle this event on the viewcomponent and use it to explictly trigger a change detection: More information about the ChangeDetectorRef can be found here: https://alligator.io/angular/change-detection-strategy/

The next edition of .NET Conf is getting closer. From September 12 until September 14, you can learn about the latest and greatest in the .NET ecosystem. From the .NET Conf site : .NET Conf is a FREE, 3 day virtual developer event co-organized by the .NET community and Microsoft. Over the course of the three days you have a wide selection of live sessions streaming here that feature speakers from the community and .NET product teams. It's a chance to learn, ask questions live, and get inspired for your next software project. You will learn to build for web, mobile, desktop, games, services, libraries and more for a variety of platforms and devices all with .NET. We have sessions for everyone, no matter if you are just beginning or are a seasoned engineer. We’ll have presentations on .NET Core and ASP.NET Core, C#, F#, Azure, Visual Studio, Xamarin, and much more.

The guys from Nrwl are introducing the Angular Console; a more approachable way to work with all the features that the Angular CLI already provides. The Angular Console is available at https://angularconsole.com/ and offers the following set of features: Trivial Code Generation: Leverage the CLI's built in generators for Components, Providers and more, all without having to remember a single command line flag. Run Custom NPM Scripts: As well as the standard `ng` commands, all of your custom npm scripts are automatically detected and allow you to run them with a single click. Discover and Install Extensions: Search through a comprehensive list of official and community schematics to extend the power of the Angular CLI even further, and install them directly in the UI. Build CLI Commands Visually: Using a visual form-driven UI, you get all of the flags and arguments for your chosen command available inline. Integrated Terminal Output: As you compose and ...

For a project I had a specific requirement where I needed to show data in a random order. Instead of doing this code, I found an easy solution to do this using raw SQL. The trick is to add an ORDER BY NewId() to your SQL statement. This is guaranteed to produce a different order every time. Let’s show a quick example using the good old Northwind database: When we execute this query, we'll see a different order everytime: Next run:

After updating to Visual Studio 2018 Update 15.8 I noticed a new menu option in Visual Studio under Build –> ASP.NET Compilation –> Optimize Build Performance for Solution: What does it do? ASP.NET projects carry a copy of the compiler to be able to compile views at runtime. However, on a developer machine when the copy of the compiler doesn’t match Visual Studio’s copy, your build performance is impacted on the order of 1-3 seconds per incremental build. Enabling this feature will update your project’s copy of the compiler to match Visual Studio’s which should speed up your incremental builds. When you select the menu option, you’ll get a screen that allows you to select all projects where to apply this change: After you click OK, Visual Studio will replace the Microsoft.Net.Compilers package with a newer Microsoft.CodeDom.Providers.DotNetCompilerPlatform package: Remark: This is applicable to ASP.NET Framework projects only, it does not apply to ASP.NET Core.

I tried Azure Service Fabric before but didn’t like it so much at that time(about 2 years ago) due to 2 reasons: Really flaky SDK and Visual Studio integration. We had a lot of problems to keep everything up and running when SDK updates where released. Lack of ecosystem around it, especially the dashboard and monitoring options were too limited compared to other solutions However after watching the following video, I think it’s time I reevaluate my opinion and give Service Fabric a second try:

Didn’t had my best day yesterday as I was trying to rollout Team Foundation Server 2018 at a customer. When we tried to start the installation, it failed while installing the .NET Framework 4.7 with a not-so-clear error message “Cannot find object or property”. Inside the setup log, we found a little more information: [1930:1564][2018-08-16T09:54:05]i319: Applied execute package: netfxfullredist, result: 0x80092004, restart: None [1930:1564][2018-08-16T09:54:05]e000: Error 0x80092004: Failed to execute EXE package. [1AC0:00A8][2018-08-16T09:54:05]i351: Removing cached package: netfxfullredist, from path: C:\ProgramData\Package Cache\76054141A492BA307595250BDA05AD4E0694CDC3\ [1AC0:00A8][2018-08-16T09:54:05]i372: Session end, registration key: SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{2b3bf919-c7d8-41a9-bff7-734a9750b00c}, resume: None, restart: None, disable resume: No [1AC0:00A8][2018-08-16T09:54:05]i330: Removed bundle dependency provider: {2b3b...

UPDATE: This is indeed an issue confirmed by Microsoft:  https://blogs.msdn.microsoft.com/sqlreleaseservices/issue-with-security-update-for-the-remote-code-execution-vulnerability-in-sql-server-2016-sp2-cu-august-14-2018/ . Thanks Michael for sending me the link. After installing the security update below on our TFS database tier, we could no longer connect to the Work hub in TFS(other features still seemed to work). The error we got on the work page was: TF246017 Team Foundation Server Could Not Connect to the Database.Verify that the server that is hosting database is operational,and that network problem are not blocking communication with server. In the windows event logs, we found the following information: A user request from the session with SPID 61 generated a fatal exception. SQL Server is terminating this session. Contact Product Support Services with the dump produced in the log directory. I couldn’t find a (better) solution, so we decided to rollback this secu...

On one of my projects, we are using a rather older version of MassTransit (version 3.5). As we needed some of the new features, we thought it was time for an upgrade. After updating all our NuGet packages, everything seemed to compile. Unfortunately when we tried to run our unit tests, every test that was using the built-in TestFramework timed out. Here is the code we were using: Problem is that the following line keeps waiting for an incoming message: var orderMessage = await _observer.PostConsumed; This code worked perfectly before in MassTransit 3.5 but not anymore in MassTransit 5.0. So what’s changed to cause this behavior? Starting from MassTransit 4, the in-memory message fabric used by the InMemoryTestFixture behaves the same as RabbitMQ. Previously, every message was published to every endpoint, regardless of whether or not there was a binding for that message type. Now, if there is no binding, the message isn't delivered. To fix it, we’ll have to a...

Writing a book about Microsoft Azure would be quite a painful experience for any editor, as the book will be outdated before it reaches the book store. Anyway, Microsoft announced an updated version of the Developer’s Guide to Microsoft Azure eBook. This updated version includes all the news from Microsoft Build, along with new services and features announced since then. The eBook ( PDF available for download ) covers the following chapters: Chapter 1: The Developer’s Guide to Azure Chapter 2: Getting started with Azure Chapter 3: Securing your application Chapter 4: Adding intelligence to your application Chapter 5: Working with and understanding IoT Chapter 6: Where and how to deploy your Azure services Chapter 7: Microsoft Azure in Action Chapter 8: Summary and where to go next Remark: EPUB and Mobi format is also available.

After switching from IIS Express to IIS, I got into trouble when I tried to start the ASP.NET Core web application through Visual Studio. When hitting F5, instead of building and launching my application, I got the following error message: Unable to start process C:\Program Files\dotnet\dotnet.exe. The web server request failed with authentication failure 401, Unauthorized. Luckily sometimes error messages can be meaningful and enabling anonymous authentication in the launchSettings.json indeed solved the problem: {   "iisSettings": {     "windowsAuthentication": false,     "anonymousAuthentication": true,     "iisExpress": {       "applicationUrl": " http://localhost:53125 ",       "sslPort": 0 }   },   "profiles": {     "I...

As mentioned in a previous post , we were encountering issues when using the Distributed Transaction Coordinator. By using the DTCTester tool we were able to prove that the problem was indeed related to the DTC settings and not a bug in our code(as if that could happen ). Executed: dtctester DSN:  test User Name: username Password: password tablename= #dtc26446 Creating Temp Table for Testing: #dtc26446 Warning: No Columns in Result Set From Executing: 'create table #dtc26446 (ival int)' Initializing DTC DtcGetTransactionManager failed: 8004d01b DtcGetTransactionManager Call Error: Indicates unable to connect to the transaction manager, or the transaction manager is unavailable. We were able to solve the issue by adding an exception for msdtc.exe in our firewall: Click on the Windows icon and start typing ‘firewall’. Choose ‘Allow an app through Windows Firewall’. The Allowed Apps window is lo...

After a datacenter move, we had some network changes that caused distributed transactions involving the DTC to fail. To help me find the root cause of the issue I used the DTC tester tool created by Microsoft. Let me explain how to use it: Installation Start by downloading this (command-line) tool here: https://www.microsoft.com/en-us/download/details.aspx?id=30746 After downloading it, you can try to run it by calling dtctester from the commandline: C:\Users\BaWu\Desktop>dtctester Too few parameters Usage: dtctester <dsn name> <user name> <password> The tool requires 3 parameters to be used; A data source name(DSN) A user name A password Creating a DSN Next step is to create a User DSN for the database we want to connect to. Click on your Windows start icon and start typing ‘data sources’ Select the ODBC Data Sources (32-bit) option. The ODBC Data Sources Administrator tool is...

In a project we had some rather complex database structure and decided to use raw SQL to query it instead of trying to tweak Entity Framework to remain performant while querying this database. One of the things we had to do was join multiple fields together into one string field separated by spaces. We originally had the following SQL to achieve this(of course this is a simplified version ): SELECT COALESCE(mad.Street, '')+' '+COALESCE(mad.Number, '')+' '+COALESCE(mad.Addition, '')+' '+COALESCE(mad.PostalCode, '')+' '+COALESCE(mad.City, '') AS Address FROM Suppliers This rather ugly SQL did its job but was not fun to look at or maintain. Starting from SQL Server 2017 you have a better alternative available: CONCAT_WS . From the documentation: This function returns a string resulting from the concatenation, or joining, of two or more string values in an end-to-end manner. It separates those concat...

Back from Holliday with a sequel for my last post. To quickly summarize our problem, we noticed very long wait times before jobs executed by the TFSJobAgent where executed. Things like triggering builds or releases, sending notifications and emails took hours before they got executed. Will diving into the TFS administration pages , we identified the TFVC_RepositoryCodeIndexing jobs used for search as the root cause of the issue. Let’s drill deeper into the problem by looking at a specific job log: Events (46099) completed with status FailedAndRetry. Event 46099 completed with message 'Patch-PeriodicCatchUp: Code patch operation for Repository Id 96f8a036-54bc-47dc-9c37-08fc23d4a07b failed with error Error code -----> MaxAcceptableFractionOfFailedItemsInCrawlerThresholdBreached Exception message -----> Could not download content of lots of files, hence failing this Job. Failed Items Count: 38, Total Items: 38. Exception type -----> Mic...