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How to Write a Smart Contract with Python on Ontology? Part 4: Native API

Reading time4 min
Views1.8K
DevOps*Python*CryptocurrenciesCryptography*Distributed systems*
Tutorial
image

Earlier, I have introduced the Ontology Smart Contract in
Part 1: Blockchain & Block API and
Part 2: Storage API
Part 3: Runtime API
Today, let’s talk about how to invoke an Ontology native smart contract through the Native API. One of the most typical functions of invoking native contract is asset transfer.
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Total votes 5: ↑5 and ↓0+5
Comments0

Tarantool Data Grid: Architecture and Features

Reading time6 min
Views2.2K
VK corporate blogLua*Tarantool*High performance*Data storage*


In 2017, we won the competition for the development of the transaction core for Alfa-Bank's investment business and started working at once. (Vladimir Drynkin, Development Team Lead for Alfa-Bank's Investment Business Transaction Core, spoke about the investment business core at HighLoad++ 2018.) This system was supposed to aggregate transaction data in different formats from various sources, unify the data, save it, and provide access to it.

In the process of development, the system evolved and extended its functions. At some point, we realized that we created something much more than just application software designed for a well-defined scope of tasks: we created a system for building distributed applications with persistent storage. Our experience served as a basis for the new product, Tarantool Data Grid (TDG).

I want to talk about TDG architecture and the solutions that we worked out during the development. I will introduce the basic functions and show how our product could become the basis for building turnkey solutions.
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Total votes 39: ↑38 and ↓1+37
Comments0

Analysis of commits and pull requests in Travis CI, Buddy and AppVeyor using PVS-Studio

Reading time10 min
Views761
PVS-Studio corporate blogBuild automation*Cloud services*GitHub*DevOps*

Picture 11

Starting from the version 7.04, the PVS-Studio analyzer for C and C++ languages on Linux and macOS provides the test feature of checking the list of specified files. Using the new mode, you can configure the analyzer to check commits and pull requests. This article covers setting up the check of certain modified files from a GitHub project in such popular CI (Continuous Integration) systems, as Travis CI, Buddy and AppVeyor.
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Total votes 21: ↑21 and ↓0+21
Comments0

Тarantool Cartridge: Sharding Lua Backend in Three Lines

Reading time8 min
Views2.5K
VK corporate blogDistributed systems*High performance*Tarantool*Lua*

In Mail.ru Group, we have Tarantool, a Lua-based application server and a database united. It's fast and classy, but the resources of a single server are always limited. Vertical scaling is also not the panacea. That is why Tarantool has some tools for horizontal scaling, or the vshard module [1]. It allows you to spread data across multiple servers, but you'll have to tinker with it for a while to configure it and bolt on the business logic.

Good news: we got our share of bumps (for example, [2], [3]) and created another framework, which significantly simplifies the solution to this problem.

Тarantool Cartridge is the new framework for developing complex distributed systems. It allows you to concentrate on writing business logic instead of solving infrastructure problems. Under the cut, I will tell you how this framework works and how it could help in writing distributed services.
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Total votes 26: ↑25 and ↓1+24
Comments0

How to Write a Smart Contract with Python on Ontology? Part 3: Runtime API

Reading time3 min
Views1.4K
DevOps*Python*CryptocurrenciesCryptography*Programming*
Tutorial
image

Introduction


Earlier, I have introduced the Ontology Smart Contract in
Part 1: Blockchain & Block API and
Part 2: Storage API
Now when you have an idea about how to call the relevant API for persistent storage when developing Python smart contract on Ontology, let’s go on to Runtime API (Contract Execution API). The Runtime API has 8 related APIs that provide common interfaces for contract execution and help developers get, convert, and validate data. Here’s a brief description of these 8 APIs:
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Rating0
Comments0

How to Write a Smart Contract with Python on Ontology? Part 2: Storage API

Reading time3 min
Views1.4K
Distributed systems*Programming*CryptocurrenciesPython*DevOps*
Tutorial
image
This is an official tutorial published earlier on Ontology Medium blog
Excited to publish it for Habr readers. Feel free to ask any related questions and suggest a better format for tutorial materials

Foreword


Earlier, in Part 1, we introduced the Blockchain & Block API of Ontology’s smart contract. Today we will discuss how to use the second module: Storage API. The Storage API has five related APIs that enable addition, deletion, and changes to persistent storage in blockchain smart contracts. Here’s a brief description of the five APIs:
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Rating0
Comments0

PVS-Studio in the Clouds: CircleCI

Reading time11 min
Views744
PVS-Studio corporate blogC++*DevOps*Development for Windows*

Picture 2

This is a new piece of our series of articles about using the PVS-Studio static analyzer with cloud CI systems. Today we are going to look at another service, CircleCI. We'll take the Kodi media player application as a test project and see if we can find any interesting bugs in its source code.
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Total votes 28: ↑26 and ↓2+24
Comments0

Automate SOAP client auto-generation routines with WSDL import for SBT and Scala

Reading time5 min
Views3.9K
DevOps*Java*Scala*

Working with SOAP often gets tricky, and dealing with WSDL might be a huge contribution to the complexity of this task. Really, it could be the least expected thing to face when you are into a modern & fancy language like for example, Scala, that is well known for its reactiveness and asynchronous way of dealing with requests. In fact, many of the software developers that have made their way into industry quite recently, might not even know about SOAP and WSDL protocols, and get quickly annoyed or even enraged when first trying to connect to such a legacy service. So, should we deprecate this altogether in favour of modern technology stack, or maybe there is a less painful solution?

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Total votes 3: ↑2 and ↓1+1
Comments0

Azure Media Services' new AI-powered innovations

Reading time6 min
Views746
Microsoft corporate blogMedia management*Cloud services*Cloud computing*Microsoft Azure*
At Microsoft, our mission is to empower every person and organization on the planet to achieve more. The media industry exemplifies this mission. We live in an age where more content is being created and consumed in more ways and on more devices than ever. At IBC 2019, we were delighted to share the latest innovations we’ve been working on and how they can help transform your media workflows. Read on to learn more.

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Total votes 2: ↑1 and ↓10
Comments0

Quintet instead of Byte — data storage and retrieval approach

Reading time13 min
Views1.8K
IT Standards*SQL*System Analysis and Design*Programming*Data storage*
Quintet is a way to present atomic pieces of data indicating their role in the business area. Quintets can describe any item, while each of them contains complete information about itself and its relations to other quintets. Such description does not depend on the platform used. Its objective is to simplify the storage of data and to improve the visibility of their presentation.



We will discuss an approach to storing and processing information and share some thoughts on creating a development platform in this new paradigm. What for? To develop faster and in shorter iterations: sketch your project, make sure it is what you thought of, refine it, and then keep refining the result.

The quintet has properties: type, value, parent, and order among the peers. Thus, there are 5 components including the identifier. This is the simplest universal form to record information, a new standard that could potentially fit any programming demands. Quintets are stored in the file system of the unified structure, in a continuous homogeneous indexed bulk of data. The quintet data model — a data model that describes any data structure as a single interconnected list of basic types and terms based on them (metadata), as well as instances of objects stored according to this metadata (data).
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Total votes 8: ↑8 and ↓0+8
Comments2

How to Write a Smart Contract with Python on Ontology? Part 1: the Blockchain & Block API

Reading time5 min
Views3.1K
Python*CryptocurrenciesDistributed systems*
From sandbox
image

This is an official tutorial published earlier on Ontology Medium blog
Excited to publish it for Habr readers. Feel free to ask any related questions and suggest a better format for tutorial materials

Foreword


In this article, we will begin to introduce the smart contract API of Ontology. The Ontology’s smart contract API is divided into 7 modules:


In this article, we will introduce the Blockchain & Block API, which is the most basic part of the Ontology smart contract system. The Blockchain API supports basic blockchain query operations, such as obtaining the current block height, whereas the Block API supports basic block query operations, such as querying the number of transactions for a given block.

Let’s get started!

First, create a new contract in SmartX and then follow the instructions below.

1. How to Use Blockchain API


References to smart contract functions are identical to Python’s references. Developers can introduce the appropriate functions as needed. For example, the following statement introduces GetHeight, the function to get the current block height, and GetHeader, the function to get the block header.
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Total votes 20: ↑18 and ↓2+16
Comments0

Tutorial For Creating Blockchain Solution on Hyperledger Composer

Reading time7 min
Views3K
System Analysis and Design*Mobile applications design*Development of mobile applications*Decentralized networks*


Due to modern business demands, IBM joined hands with other companies to develop an open-source business blockchain network called Hyperledger Fabric project that is touching the sky. Due to modular architecture, digital keys, and on-demand data retrieval, hyperledger fabric is regarded as the base for the world’s future modular architecture blockchain-based apps. Further benefits of Hyperledger Fabric are given below to facilitate your interpretation.
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Total votes 7: ↑6 and ↓1+5
Comments0

Vepp — ISPsystem’s new server and website control panel

Reading time9 min
Views1.2K
ISPsystem corporate blogWebsite development*Hosting


Vepp is our new panel for managing servers and websites. At first, we just wanted to transform the interface of ISPmanager 5 but at the designing phase, we figured that (changing) the interface is not enough. We have to change the approach to modern user’s needs and tasks. As a matter of fact, it meant that we had to create a whole new product.


In the article, we’ll explain why we couldn’t make do with only cosmetic changes to ISPmanager 5 and show the result of the global overhaul.

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Total votes 6: ↑6 and ↓0+6
Comments0

DPKI: Addressing the Disadvantages of Centralized PKI by Means of Blockchain

Reading time15 min
Views3.1K
ENCRY corporate blogDecentralized networks*Information Security*Cryptography*Network technologies*


Digital certificates are one of the most commonly known auxiliary tools that help protect data across public networks. However, the key disadvantage of this technology is also commonly known: users are forced to implicitly trust certification authorities which issue digital certificates. Andrey Chmora, Technology and Innovations Director at ENCRY, suggested a new approach for building a Public Key Infrastructure (PKI) to eliminate the existing disadvantages using the distributed ledger (blockchain) technology.
Let's begin with the basics.
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Total votes 4: ↑3 and ↓1+2
Comments0

Lessons learned from testing Over 200,000 lines of Infrastructure Code

Reading time11 min
Views3.2K
Configuring Linux*DevOps*IT Infrastructure*IT systems testing*


IaC (Infrastructure as Code) is a modern approach and I believe that infrastructure is code. It means that we should use the same philosophy for infrastructure as for software development. If we are talking that infrastructure is code, then we should reuse practices from development for infrastructure, i.e. unit testing, pair programming, code review. Please, keep in mind this idea while reading the article.


Russian Version

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Total votes 5: ↑5 and ↓0+5
Comments4

Configuration of the Warnings Next Generation plugin for integration with PVS-Studio

Reading time3 min
Views1.7K
PVS-Studio corporate blogIT systems testing*IT Infrastructure*Development Management*DevOps*

Picture 4


The PVS-Studio 7.04 release coincided with the release of the Warnings Next Generation 6.0.0 plugin for Jenkins. Right in this release Warnings NG Plugin added support of the PVS-Studio static code analyzer. This plugin visualizes data related to compiler warnings or other analysis tools in Jenkins. This article will cover in detail how to install and configure this plugin to use it with PVS-Studio, and will describe most of its features.
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Total votes 34: ↑33 and ↓1+32
Comments0

Bypassing LinkedIn Search Limit by Playing With API

Reading time7 min
Views17K
Social networks and communitiesReverse engineering*JavaScript*Data storage*API*
Translation
[Because my extension got a lot of attention from the foreign audience, I translated my original article into English].

Limit


Being a top-rated professional network, LinkedIn, unfortunately, for free accounts, has such a limitation as Commercial Use Limit (CUL). Most likely, you, same as me until recently, have never encountered and never heard about this thing.

image

The point of the CUL is that when you search people outside your connections/network too often, your search results will be limited with only 3 profiles showing instead of 1000 (100 pages with 10 profiles per page by default). How ‘often’ is measured nobody knows, there are no precise metrics; the algorithm decides it based on your actions – how frequently you’ve been searching and how many connections you’ve been adding. The free CUL resets at midnight PST on the 1st of each calendar month, and you get your 1000 search results again, for who knows how long. Of course, Premium accounts have no such limit in place.

However, not so long ago, I’ve started messing around with LinkedIn search for some pet-project, and suddenly got stuck with this CUL. Obviously, I didn’t like it that much; after all, I haven’t been using the search for any commercial purposes. So, my first thought was to explore this limit and try to bypass it.

[Important clarification — all source materials in this article are presented solely for informational and educational purposes. The author doesn't encourage their use for commercial purposes.]
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Total votes 10: ↑9 and ↓1+8
Comments3

How we created IoT system for managing solar energy usage

Reading time5 min
Views1.3K
Big Data*IT Infrastructure*System Analysis and Design*IOTSmart House

If you have no idea about the development architecture and mechanical/electrical design behind IoT solutions, they could seem like "having seemingly supernatural qualities or powers". For example, if you show a working IoT system to 18th century people, they'd think it's magic.This article is sort of busting such myth. Or, to put it more technically, about hints for fine-tuning the IoT development for an awesome project in solar energy management area.

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Total votes 9: ↑7 and ↓2+5
Comments0
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