Some time ago, in a discussion on one of SObjectizer's releases, we were asked: "Is it possible to make a DSL to describe a data-processing pipeline?" In other words, is it possible to write something like that:
A | B | C | D
and get a working pipeline where messages are going from A to B, and then to C, and then to D. With control that B receives exactly that type that A returns. And C receives exactly that type that B returns. And so on.
It was an interesting task with a surprisingly simple solution. For example, that's how the creation of a pipeline can look like:
auto pipeline = make_pipeline(env, stage(A) | stage(B) | stage(C) | stage(D));Or, in a more complex case (that will be discussed below):
auto pipeline = make_pipeline( sobj.environment(),
stage(validation) | stage(conversion) | broadcast(
stage(archiving),
stage(distribution),
stage(range_checking) | stage(alarm_detector{}) | broadcast(
stage(alarm_initiator),
stage( []( const alarm_detected & v ) {
alarm_distribution( cerr, v );
} )
)
) );In this article, we'll speak about the implementation of such pipeline DSL. We'll discuss mostly parts related to stage(), broadcast() and operator|() functions with several examples of usage of C++ templates. So I hope it will be interesting even for readers who don't know about SObjectizer (if you never heard of SObjectizer here is an overview of this tool).
I don’t care what your dragon’s said, it’s a lie. Dragons lie. You don’t know what’s waiting for you on the other side.This article is based on the post in the Krister Walfridsson’s blog, “Why undefined behavior may call a never called function?”.
Michael Swanwick, The Iron Dragon’s Daughter
SObjectizer is a rather small C++ framework that simplifies the development of multithreaded applications. SObjectizer allows a developer to use approaches from Actor, Publish-Subscribe and Communicating Sequential Processes (CSP) models. It's an OpenSource project that is distributed under BSD-3-CLAUSE license.
SObjectizer has a long history. SObjectizer itself was born in 2002 as SObjectizer-4 project. But it was based on ideas from previous SCADA Objectizer that was developed between 1995 and 2000. SObjectizer-4 was open-sourced in 2006, but its evolution was stopped soon after that. A new version of SObjectizer with the name SObjectizer-5 was started in 2010 and was open-sourced in 2013. The evolution of SObjectizer-5 is still in progress and SObjectizer-5 has incorporated many new features since 2013.
SObjectizer is more or less known in the Russian segment of the Internet, but almost unknown outside of the exUSSR. It's because the SObjectizer was mainly used for local projects in exUSSR-countries and many articles, presentations, and talks about SObjectizer are in Russian.
Multithreading is used in Parallel computing as well as in Concurrent computing. But there is a big difference between Parallel and Concurrent computing. And, as a consequence, there are tools targeted Parallel computing, and there are tools for Concurrent computing, and they are different.
I'm putting part of older WebForms portions of my site that still run on bare metal to ASP.NET Core and Azure App Services, and while I'm doing that I realized that I want to make sure my staging sites don't get indexed by Google/Bing.
I already have a robots.txt, but I want one that's specific to production and others that are specific to development or staging. I thought about a number of ways to solve this. I could have a static robots.txt and another robots-staging.txt and conditionally copy one over the other during my Azure DevOps CI/CD pipeline.
Then I realized the simplest possible thing would be to just make robots.txt be dynamic. I thought about writing custom middleware but that sounded like a hassle and more code that needed. I wanted to see just how simple this could be.
LZ_decompress_fast function near the top. What is going on? This question had us wondering how to choose the best compression algorithm. 
If you were asked to draw a picture of several people in ski gear, standing in the snow, chances are you’d start with an outline of three or four people reasonably positioned in the center of the canvas, then sketch in the skis under their feet. Though it was not specified, you might decide to add a backpack to each of the skiers to jibe with expectations of what skiers would be sporting. Finally, you’d carefully fill in the details, perhaps painting their clothes blue, scarves pink, all against a white background, rendering these people more realistic and ensuring that their surroundings match the description. Finally, to make the scene more vivid, you might even sketch in some brown stones protruding through the snow to suggest that these skiers are in the mountains.
Now there’s a bot that can do all that.
Since its completion more than 675 years ago, the medieval cathedral of Notre-Dame has captivated millions of people with its incomparable beauty. From its legendary stained glass rose window to its towering spire, it’s widely regarded as one of the most stunning examples of medieval architecture in history.
Hi everyone!
I like Tox and respect the participants of this project and their work. In an effort to help Tox developers and users, I looked into the code and noticed potential problems that could lead to a false sense of security. Since I originally published this article in 2016 (in Russian), many improvements have been made to Tox, and I lead a team that re-wrote secure Tox software from scratch using the Rust programming language (check out Tox-rs). I DO recommend using tox in 2019. Let's take a look what actually made us rewrite Tox in Rust.
There is an unhealthy tendency to overestimate the security of E2E systems only on the basis that they are E2E. I will present objective facts supplemented with my own comments for you to draw your own conclusions.
Spoiler: The Tox developers agree with my points and my source code pull request was accepted.
This week I spent coding my very first public pet-app based on Telegram chat bot which acts as a Bitcoin wallet and allows to send and receive tips between Telegram users and other so-called “Lightning Apps”. I assume that you are familiar with Bitcoin & Telegram in general, i’ll try to post short and without deep jump into details. More resources about Bitcoin can be found here and Telegram is simply an instant messenger that allows you to create your custom apps (chat-bots) using their platform.
something like this…
The increase of Internet censorship by authoritarian regimes expands the blockage of useful internet resources making impossible the use of the WEB and in essence violates the fundamental right to freedom of opinion and expression enshrined in the Universal Declaration of Human Rights.
Article 19
Everyone has the right to freedom of opinion and expression; this right includes freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers.
The following is the detailed 6 steps instruction for non-IT people to deploy free* VPN service upon Wireguard technology in Amazon Web Services (AWS) cloud infrastructure, using a 12 months free account, on an Instance (virtual machine) run by Ubuntu Server 18.04 LTS.
I tried to make this walkthrough as friendly as possible to people far from IT. The only thing required is assiduity in repeating the steps described below.
Intro
