We are now publishing .NET Core container images to Microsoft Container Registry (MCR). We have also made other changes to the images we publish, described in this post.

Important: You will need to change FROM statements in Dockerfile files and docker pull commands as a result of these changes. 3.0 references need to be changed now. Most 1.x and 2.x usages can be changed over time. The new tag scheme is decribed in this post and are provided at the microsoft-dotnet-core repo, our new home on Docker Hub.

Summary of changes:

• .NET Core images are now published to Microsoft Container Registry.
• Updates will continue to be published to Docker Hub, for .NET Core 1.x and 2.x.
• .NET Core 3.0 will only be published to MCR.
• Nano Server 2016 images are no longer supported or published.

Disposable pattern (Disposable Design Principle)

I guess almost any programmer who uses .NET will now say this pattern is a piece of cake. That it is the best-known pattern used on the platform. However, even the simplest and well-known problem domain will have secret areas which you have never looked at. So, let’s describe the whole thing from the beginning for the first-timers and all the rest (so that each of you could remember the basics). Don’t skip these paragraphs — I am watching you!

If I ask what is IDisposable, you will surely say that it is

public interface IDisposable
{
    void Dispose();
}

What is the purpose of the interface? I mean, why do we need to clear up memory at all if we have a smart Garbage Collector that clears the memory instead of us, so we even don’t have to think about it. However, there are some small details.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

• First of all, you can read this article in russian here.

One evening, I was reading Mastering regular expressions by Jeffrey Friedl , I realized that even if you have all the documentation and a lot of experience, there could be a lot of tricks developed by different people and imprisoned for themselves. All people are different. And techniques that are obvious for certain people may not be obvious to others and look like some kind of weird magic to third person. By the way, I already described several such moments here (in russian) .

For the administrator or the user the command line is not only a tool that can do everything, but also a highly customized tool that could be develops forever. Recently there was a translated article about some useful tricks in CLI. But I feel that the translator do not have enough experience with CLI and didn't follow the tricks described, so many important things could be missed or misunderstood.

Under the cut — a dozen tricks in Linux shell from my personal experience.

It has been three months since 2018 had ended. For many, it has just flew by, but for us, PVS-Studio developers, it was quite an eventful year. We were working up a sweat, fearlessly competing for spreading the word about static analysis and were searching for errors in open source projects, written in C, C++, C#, and Java languages. In this article, we gathered the top 10 most interesting of them right for you!

What's new in CUBA 7

Three years ago we announced the second publicly available major version of the framework. CUBA 6 was the game-changing version — the licensing was turned from proprietary to Apache 2.0. Those days we couldn't even guess where it was going to bring the framework in long term. CUBA community started to grow exponentially, so we have learned a lot of possible (and sometimes impossible) ways of how developers use the framework. Now we are happy to announce CUBA 7, which, we hope, will make development more coherent and joyful for all community members from those just starting their journey in CUBA and Java to skilled enterprise developers and Java experts.

It is new selection of tips and tricks about Python and programming from my Telegram-channel @pythonetc.

Previous publications.

Structures comparing

Sometimes you want to compare complex structures in tests ignoring some values. Usually, it can be done by comparing particular values with the structure:

For Russian speaking posted translated version here.

This is how Alex Viscreanu’s talk on Moscow Python Conf++ named. Now it's two weeks till before the conference, but of course, I've already heard what Alex will speak about. Find below some spoilers and talk preparing backstage: what kind of an open source Zoo developed in Kiwi, how it tests Python code and what’s the difference between The Zoo and for example mypy.

— Tell us a bit about Kiwi, yourself and what is your work within a company?

Kiwi.com is an online travel agency based in Czech Republic. We aim to make travelling as simple and accessible as possible. The company was founded in 2012 as Skypicker, and since then it has become one of the five biggest online sellers of airline tickets in Europe. It was renamed to Kiwi.com in 2016.

The special feature that we, at Kiwi.com, offer is the virtual interlining, which allows us to connect flights from companies that don’t usually cooperate together, and we are covering the possible connection issues caused by delayed flights.

Some of the numbers that we manage at Kiwi.com include 90 000 000+ daily searches, 25 000 seats sold daily, and a total of 15 000 000 000+ flight combinations available.

Here we are, continuing to explore the code of calculators! Today we are going to take a look at the project called SpeedCrunch, the second most popular free calculator.

Introduction

SpeedCrunch is a high-precision scientific calculator featuring a fast, keyboard-driven user interface. It is free and open-source software, licensed under the GPL and running on Windows, Linux, and macOS.

The source code is available on BitBucket. I was somewhat disappointed by the build documentation, which could be more detailed. It says that you need «Qt 5.2 or later» to build the project, but it actually required a few specific packages, which wasn't easy to figure out from the CMake log. By the way, it is considered a good practice nowadays to include a Dockerfile into the project to make it easier for the user to set up the development environment.

Starting from .NET Core 2.0 and .NET Framework 4.5 we can use new data types: Span and Memory. To use them, you just need to install the System.Memory nuget package:

PM> Install-Package System.Memory

These data types are notable because the CLR team has done a great job to implement their special support inside the code of .NET Core 2.1+ JIT compiler by embedding these data types right into the core. What kind of data types are these and why are they worth a whole chapter?

If we talk about problems that made these types appear, I should name three of them. The first one is unmanaged code.

Both the language and the platform have existed for many years along with means to work with unmanaged code. So, why release another API to work with unmanaged code if the former basically existed for many years? To answer this question, we should understand what we lacked before.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

Some days ago we announced the availability of our release candidate (RC) of TypeScript 3.4. Our hope is to collect feedback and early issues to ensure our final release is simple to pick up and use right away.

To get started using the RC, you can get it through NuGet, or use npm with the following command:

npm install -g typescript@rc

You can also get editor support by

• Downloading for Visual Studio 2017 (for version 15.2 or later)
• Following directions for Visual Studio Code and Sublime Text.

Let’s explore what’s new in 3.4!

Starting with Visual Studio 2019 Preview 4 and RC, we’ll be adjusting how C# versions are treated in .NET tooling. Read more below <cut>.

Summary of changes

Firstly, we’re adding two new Language Version (LangVersion) values: LatestMajor and Preview. Here’s how they stack up with the currently supported list of values:

How often do you get to 404 pages? Usually, they are not styled and stay default. Recently I’ve found test.do.am which interactive character attracts attention and livens up the error page.

Probably, there was just a cat picture, then they thought up eyes movement and developer implemented the idea.Now user visits the page and checks out the effect. It’s cool and pleasant small feature, it catches, then user discusses it with colleagues or friends and even repeats the feature. It could be this easy, if not:

Previously we did code reviews of large mathematical packages, for example, Scilab and Octave, whereby calculators remained aloof as small utilities, in which it is difficult to make errors due to their small codebase. We were wrong that we haven't paid attention to them. The case with posting the source code of the Windows calculator showed that actually everyone was interested in discussing types of errors hiding in it. Moreover, the number of errors there was more than enough to write an article about that. My colleagues and I, we decided to explore the code of a number of popular calculators, and it turned out that the code of the Windows calculator was not that bad (spoiler).

Today, we’re excited to announce that we are open sourcing Windows Calculator on GitHub under the MIT License. This includes the source code, build system, unit tests, and product roadmap. Our goal is to build an even better user experience in partnership with the community. We are encouraging your fresh perspectives and increased participation to help define the future of Calculator.

Blazor 0.9.0 is now available! This release updates Blazor with the Razor Components improvements in .NET Core 3.0 Preview 3.

New Razor Component improvements now available to Blazor apps:

• Improved event handling
• Forms & validation

Hi, my name is Vladislav, and I am a member of the Tarantool development team. Tarantool is a DBMS and an application server all in one. Today I am going to tell the story of how we implemented horizontal scaling in Tarantool by means of the VShard module.

Some basic knowledge first.

There are two types of scaling: horizontal and vertical. And there are two types of horizontal scaling: replication and sharding. Replication ensures computational scaling whereas sharding is used for data scaling.

Sharding is also subdivided into two types: range-based sharding and hash-based sharding.

Range-based sharding implies that some shard key is computed for each cluster record. The shard keys are projected onto a straight line that is separated into ranges and allocated to different physical nodes.

Hash-based sharding is less complicated: a hash function is calculated for each record in a cluster; records with the same hash function are allocated to the same physical node.

I will focus on horizontal scaling using hash-based sharding.

Discovering git vendor extension.

Cross-post from my medium blog: https://medium.com/opsops/git-vendor-295db4bcec3a

I would like to introduce the proper way to handle vendoring of git repositories.

What is is ‘vendoring’?

Vendoring is a way to integrate other’s work into your own. It’s the opposite of ‘linking’ against third-party library. Instead of having that library as a dependency, application uses this library as a part of own source code and keep that code ‘inside’ itself.

Normally, vendoring is done by language tooling: bundler, cargo, pip, etc. But sometimes you need to vendor something not covered by any existing toolset, or something multi-language, that it’s impossible to find the ‘core’ language tool for that.

The solution for this situation is vendoring on a git level. You have your own git repository (I call it ‘destination repo’), and you want to incorporate some other repository (I call it ‘source repo’) as a directory into your (destination repo).

The things you expect from a well-designed vendoring system (regardless of Git it is or not):

• Visibility. You want to know that some code is vendored, means it wasn’t written by committer.

In autumn, we announced we were going to expand our IT team from 49 to 250 developers. And immediately we were buried under an avalanche of questions — mostly, people were interested why a pizza chain needs so many software engineers. How did we come up with such a number? So now I want to answer that.

As announced in the previous post, on March 3 (the first Sunday of March) Mail.ru Group’s Moscow office will be hosting the third international Lua conference, Lua in Moscow 2019. See schedule details under the cut.

Why do so many programmers hate UI work? Because it is tedious. Especially, for the Web, but other types of UI are only slightly easier. Layouts, margins, paddings — neverending stream of little tweaks to make it look OK on all sane environments, and somehow this freaking button sometimes overlaps that input field. Rrrr! And yes, it should not hang on button clicks, which means a lot of asynchronous programming, which is a nightmare.

And don’t even speak about aesthetics and usability! Choose right colours, element sizes and locations, find/draw images and put them where they fit, think about user workflows — isn’t it a designers’ or Ux specialists’ job?! Leave me alone, I’m a programmer. I work with backend layers, where everything is straightforward and linear, there are no buttloads of different environments to adjust to, and design is guided by mere logic without pesky fussing with ‘user friendliness’ and ’beauty’!