Language Selection

English French German Italian Portuguese Spanish

Programming Leftovers

Submitted by Roy Schestowitz on Monday 20th of May 2019 10:02:42 AM Filed under
Development
  • Richard W.M. Jones: NBD’s state machine

    Eric and I are writing a Linux NBD client library. There were lots of requirements but the central one for this post is it has to be a library callable from programs written in C and other programming languages (Python, OCaml and Rust being important), and we don’t control those programs so they may be single or multithreaded, or may use non-blocking main loops like gio and glib.

    An NBD command involves sending a request over a socket to a remote server and receiving a reply. You can also have multiple requests “in flight” and the reply can be received in multiple parts. On top of this the “fixed newstyle” NBD protocol has a complex multi-step initial handshake. Complicating it further we might be using a TLS transport which has its own handshake.

    It’s complicated and we mustn’t block the caller.

    There are a few ways to deal with this in my experience — one is to ignore the problem and insist that the main program uses a thread for each NBD connection, but that pushes complexity onto someone else. Another way is to use some variation of coroutines or call/cc — if we get to a place where we would block then we save the stack, return to the caller, and have some way to restore the stack later. However this doesn’t necessarily work well with non-C programming languages. It likely won’t work with either OCaml or Ruby’s garbage collectors since they both involve stack walking to find GC roots. I’d generally want to avoid “tricksy” stuff in a library.

  • PyDev of the Week: Adrienne Tacke

    This week we welcome Adrienne Tacke (@AdrienneTacke) as our PyDev of the Week! Adrienne is the author of Coding for Kids: Python: Learn to Code with 50 Awesome Games and Activities and her book came out earlier this year.

  • Python Programming - if, else and elif
  • Subsecond deployment and startup of Apache Camel applications

    The integration space is in constant change. Many open source projects and closed source technologies did not withstand the tests of time and have disappeared from the middleware stacks for good. After a decade, however, Apache Camel is still here and becoming even stronger for the next decade of integration. In this article, I’ll provide some history of Camel and then describe two changes coming to Apache Camel now (and later to Red Hat Fuse) and why they are important for developers. I call these changes subsecond deployment and subsecond startup of Camel applications.

  • Best Free Books to Learn about Lua

    Lua is a lightweight, small, compact, and fast programming language designed as an embeddable scripting language. This cross-platform interpreted language has a simple syntax with powerful data description constructs. It has automatic memory management and incremental garbage collection, making it ideal for configuration, scripting, and rapid prototyping. Lua tries to help you solve problems with only hundreds of lines, or even less. To achieve this aim, Lua relies on extensibility.

    In the popularity stakes, Lua lags behind say Python, Perl, or Ruby for scripting purposes. As a barometer of its popularity, Lua is currently ranked in 33rd place on the TIOBE Index.

    Lua is not designed to develop standalone software. But Lua excels as a secondary language. Witness Lua cropping up in kernels, tools, and games. Lua was designed, from the beginning, to be integrated with software written in C and other conventional languages. But it’s also used as a standalone language.

    This language is free software distributed under the terms of the MIT license. Lua’s developers consist of a team at PUC-Rio, the Pontifical Catholic University of Rio de Janeiro in Brazil. The language has been in development for 26 years.

    This article recommends free books to help you master programming in Lua. As the range of good free books is fairly limited, I close the article with a few carefully selected tutorials that are genuinely useful.

»

More in Tux Machines

digiKam 7.7.0 is released

After three months of active maintenance and another bug triage, the digiKam team is proud to present version 7.7.0 of its open source digital photo manager. See below the list of most important features coming with this release. Read more

Dilution and Misuse of the "Linux" Brand

Samsung, Red Hat to Work on Linux Drivers for Future Tech

The metaverse is expected to uproot system design as we know it, and Samsung is one of many hardware vendors re-imagining data center infrastructure in preparation for a parallel 3D world. Samsung is working on new memory technologies that provide faster bandwidth inside hardware for data to travel between CPUs, storage and other computing resources. The company also announced it was partnering with Red Hat to ensure these technologies have Linux compatibility. Read more

today's howtos

  • How to install go1.19beta on Ubuntu 22.04 – NextGenTips

    In this tutorial, we are going to explore how to install go on Ubuntu 22.04 Golang is an open-source programming language that is easy to learn and use. It is built-in concurrency and has a robust standard library. It is reliable, builds fast, and efficient software that scales fast. Its concurrency mechanisms make it easy to write programs that get the most out of multicore and networked machines, while its novel-type systems enable flexible and modular program constructions. Go compiles quickly to machine code and has the convenience of garbage collection and the power of run-time reflection. In this guide, we are going to learn how to install golang 1.19beta on Ubuntu 22.04. Go 1.19beta1 is not yet released. There is so much work in progress with all the documentation.

  • molecule test: failed to connect to bus in systemd container - openQA bites

    Ansible Molecule is a project to help you test your ansible roles. I’m using molecule for automatically testing the ansible roles of geekoops.

  • How To Install MongoDB on AlmaLinux 9 - idroot

    In this tutorial, we will show you how to install MongoDB on AlmaLinux 9. For those of you who didn’t know, MongoDB is a high-performance, highly scalable document-oriented NoSQL database. Unlike in SQL databases where data is stored in rows and columns inside tables, in MongoDB, data is structured in JSON-like format inside records which are referred to as documents. The open-source attribute of MongoDB as a database software makes it an ideal candidate for almost any database-related project. This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo‘ to the commands to get root privileges. I will show you the step-by-step installation of the MongoDB NoSQL database on AlmaLinux 9. You can follow the same instructions for CentOS and Rocky Linux.

  • An introduction (and how-to) to Plugin Loader for the Steam Deck. - Invidious
  • Self-host a Ghost Blog With Traefik

    Ghost is a very popular open-source content management system. Started as an alternative to WordPress and it went on to become an alternative to Substack by focusing on membership and newsletter. The creators of Ghost offer managed Pro hosting but it may not fit everyone's budget. Alternatively, you can self-host it on your own cloud servers. On Linux handbook, we already have a guide on deploying Ghost with Docker in a reverse proxy setup. Instead of Ngnix reverse proxy, you can also use another software called Traefik with Docker. It is a popular open-source cloud-native application proxy, API Gateway, Edge-router, and more. I use Traefik to secure my websites using an SSL certificate obtained from Let's Encrypt. Once deployed, Traefik can automatically manage your certificates and their renewals. In this tutorial, I'll share the necessary steps for deploying a Ghost blog with Docker and Traefik.

More on Tux Machines: About ● Gallery ● Forum ● Blogs ● Search ● News ● RSS Feed

Part of Bytes Media ● Sister sites below.

TechBytes Techrights button

Powered by Drupal, an open source content management system

Content available under CC-BY-SA CC

© by original authors

Powered by CentOS 6.5 (GNU/Linux), Varnish, and Drupal 6