Using Apache Kafka for Asynchronous Communication in Microservices

  • In this post, we’ll look at how to set up an Apache Kafka instance, create a user service to publish data to topics, and build a notification service to consume data from those topics.
  • One of the required configuration options for the Kafka service is , which tells Kafka where to find the Zookeeper instance.
  • To publish data to a Kafka topic, we are going to create a user service that provides two endpoints: – – We use the NPM package to create a producer that connects to Kafka from our node app: – – We create a new promise object that resolves to a…
  • This is used in our function, which publishes data to a Kafka topic partition: – – To consume data from our Kafka topic, we are going to create a notification service that listens for data coming from our topics and sends an email with either a verification code or success…
  • Our two-factor authentication app demonstrates the communication pattern between only two microservices using Apache Kafka (there are other systems like RabbitMQ, ZeroMQ), but by decoupling communication between those services, we add flexibility for the future.

if you’re considering microservices, you have to give serious thought to how the different services will communicate. In this post, we’ll look at how to set up an Apache Kafka instance, create a user service to publish data to topics, and build a notification service to consume data from those topics.
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React.js Overview via Alex Azarov  #webdev

React.js Overview via Alex Azarov  #webdev

  • Comparing React.js with Angular or other MVC frameworks makes no sense since React is just a representation.
  • Thus, a = b + c, and A will always depend on the values of B an C. – – React constantly works with the DOM, re-rendering it when conditions change (the part of the DOM that is changed by React.js is called a component).
  • Prior to React, such a practice would have seriously affected the application’s performance, but the developers of React.js approached this problem quite radically: they completely rewrote the DOM in JavaScript.
  • An important feature of React.js is the use of JSX.
  • There exist other extensions for React.js, however, considering the “weight” of the framework, their use should be minimized.

A discussion of the React.js web development framework, the pros and cons of this development tool, and who would be best suited using React in their projects.
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Getting Started With React Programming

Getting Started With #ReactProgramming by @KumarPraveen179 cc @CsharpCorner  #Reactjs

  • You should know the basic concepts of JavaScript like – – – Basically, it is a JavaScript library for building user interfaces.
  • We can say that it’s a new type of JS library, offering a new approach to build/update a View.
  • It creates a virtual DOM to track the changes when the application state is updated and uses the virtual DOM to update only those parts of a page which have been changed.
  • It was first deployed on Facebook’s Newsfeed in 2011 and after that, on – – Where To Use React – – As we discussed above, it’s a JavaScript library so, it is possible to use React everywhere where JavaScript code can be executed.
  • In the upcoming article, I will explain more about virtual DOM using programming example along with the graphical view.

React is a JavaScript library for building user interfaces. It is developed by Facebook to facilitate the building with the interactive, stateful and reusable UI components.
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Query Components with Apollo – Kureev Alexey – Medium

  • After Apollo takes care of fetching and mapping props to query parameters, query component uses “function-as-a-child” approach to expose a child-independent API with injected data.Comparing to the standard approach were you add a graphql wrapper to your higher-order components, query components have a set of advantages:Testability.
  • Query Components abstracts out your data management layer so you can focus on business logic and change underlying implementation if needed.Once a Query Component is defined, it can be used as an any other component in your application:A nice side effect of decoupling higher-order components into Query Components is minimizing…
  • If the data management layer grows, it won’t affect presenter components unless they have to reflect new data properties.Mutations with Query ComponentsMutations are not that straightforward as queries.
  • For example:Therefore, you can use this component in a similar way:So the concept is the same: Query Component receives a bunch of props that are later on used as parameters for the mutation query.Testing Query Components like a Pro 😎How to test Query Components?When it comes to testing, Apollo-based components have…
  • In other words, we check if given data.x complies to the shape of the mock that was passed to the fake client during initialization.And the last, but not least: query component should call a children function with the data, pulled from Apollo.

A couple of months ago, we started to use Apollo Client (+React Native) at Werkspot. From the very beginning, Apollo overwhelmed us by the simplicity and flexibility it provides. It inspired us to…
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How to Style React Components with styled-component

  • With components, it has started to make more sense to include styling inline within a component like so:source: www.styled-components.comWhy Inline Styling?You may be thinking to yourself, isn’t inline styling bad practice?
  • In the case of components though, inline styling has many advantages over vanilla CSS styling.
  • Acording to Radium’s website (another tool for inline styling) the benefits of using inline styling with components are:Scoped styles without selectors (styles are on component itself)Avoids specificity conflicts (two style definitions for one element)Source order independence (doesn’t rely on the order files are imported)Dead code elimination (no unused classes as in CSS)Highly expressive (easier to read JSX)Original using styled-components— cool.
  • extend“ syntax.Styling with styled-componentsResulting WebpageFinishing UpInline styling of components is a powerful option to consider when building out user interfaces with React.
  • There is a lot more that styled-components is capable of and I recommend looking through there tutorials and guides to get a better understanding of how awesome inline styling of your components can be!

Traditional styling of websites relies on having an external stylesheet with CSS. This tradition has been challenged with the advent of React and component based UI design. With components, it has…
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Redux middleware logging basics – Ben Garrison – Medium

Redux middleware logging basics  #beer #javascript #middleware #redux #react #reactjs

  • Wouldn’t it be great to be able to go back and look at the exact state of the application at the time of the crash and even the actions that led up to the crash?
  • You would have to spread these things all over your application to catch your store at different phases of change.
  • When you are working on larger apps however, there are advantages to having a single definition point.
  • Let’s see how that may look:You can see above that we have combined 3 middleware:Our new custom loggerRedux Thunk for handling asynch callsRouterMiddleware that captures and redirects actions to your historyYou can combine middleware and they have no need to know about the ‘ware that proceeds or follows them.
  • The moment between the Action and the Reducer is a critical exchange and using middleware to cleanly log state can improve the overall quality of your app.

I have written previously about REDUX and some of its features, if you are interested in a more general introduction, please check out the post below. Implementing this FLUX-style architecture has…
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Isomorphic Javascript — Javascript all the things

  • With the creation of node.js and increasing popularity of single page javascript applications, it’s only natural to want to javascript all the things.
  • Using a single language on the client and server allows for many advantages in today’s world, but there are also some pitfalls that need to be considered.
  • In this talk we will cover:

    • What is isomorphic JavaScript

    • What does server side render of JS look like

    • How is it possible to use the same language and frameworks in client and server side code

    • What benefits can be gained by using a common language and framework.

  • Join us as Jarrod Zywein shows us how to JavaScript ALL THE THINGS.

Iso-who-now? Iso-what-what?
With the creation of node.js and increasing popularity of single page javascript applications, it’s only natural to want to jav
Continue reading “Isomorphic Javascript — Javascript all the things”