What does “Service.EndpointSpec.Mode” changes on docker swarm

That is the point. Mode is an enum, it can be “vip” or “dnsrr”. As one easily guess, “vip” does not stand for Very Important Person. Why should you have the option to assign a Virtual IP or load balance the traffic by DNS Round Robin policy? I asked this question myself while developing smgoservice […]

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How to scrape HTML page by DOM and XPath

I decided to release this code snip, just a PHP class, for extracting data from an HTML page. The code is in https://github.com/danielecr/verygrabber and the packagist can be installed by composer install smartango/verygrabber rif. https://packagist.org/packages/smartango/verygrabber This is an old snippet to define a grabber by XPath deploying the recursive nature of DOM (Document Object Model) […]

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How to solve network problem on docker swarm

Having different version of docker running on different nodes, it happens to experiencing problems. Docker Swarm is a community project maintained in https://github.com/moby/moby github repository, it lack a number of features that are provided by kubernetes, but still someone is using this for experimental and bridge-to-kubernetes, because it is very simple to understand and manage. […]

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How to implement Authorisation Workflow for Amazon SP API

Amazon Selling Partner API documents two kinds of authorization workflow, one starting from your website app https://developer-docs.amazon.com/sp-api/docs/website-authorization-workflow, and the other one starting from the Amazon App store. Authorize from your website While implementing the authorize workflow from your website, you start assuming that the user is already logged in. This means the browser is keeping a […]

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Error Management: Go vs Rust vs Exception-based

I want to write some reference for error management in Rust and in Go, versus exception-class based language, maybe Python deserve a specific session, I will update that, but basically the point of exception-based error management is the sub-classing of a Exception class and the try {…} catch(…) {…} block for handling exceptional cases Golang […]

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multi stage rocket flying

Dive into (useless?) uncovered case of multistage dockerfile

Looking at the upstream documentation of Multi-stage builds there are some examples but this is missing: Ok, I mean, the example by itself is useless, but “it works”. Try: docker build -f Dockerfile -t copiedfrom-rust:v0.1 . Then: docker run -it copiedfrom-rust:v0.1 sh Real use case scenario Lets get serious now: why? Suppose you are inside […]

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DAGs from Graph

Still ChatGPT. But bad experience this time. I asked all possible distinct DAGs given an adjacency matrix of a graph (probably not connected). I insisted that the graph is not connected. But “it” pretended to just make a loop over the nodes and build “all possible dags” (it pretends). I must note that the solution […]

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The Power of Windows in Rust: Unleashing the Potential of Sequential Data

Just catch a glimpse from your windows (it was: “introduction”) The windows method in Rust’s standard library is a powerful tool for processing sequential data. It enables efficient iteration over fixed-size, overlapping windows of elements in a collection, offering a functional and concise approach to data manipulation. This article will discuss the usefulness of the […]

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