Introduction Whenever a developer or system admin faces an issue with the system, the first instinct is to look at the logs. For a long time, we have relied on basic tools like grep, awk, or perl to perform log analysis. However, with changing times and cloud-scale applications, the earlier techniques no longer suffice. Imagine a system with tens, hundreds, or thousands of hosts. There are multiple instances of different applications running on all these hosts.
Introduction Understanding the performance of mission critical API is crucial. Before you deploy your API, probably you want to know, how your API behaves under heavy loads. Most API nowadays are HTTP-based, and that’s why there are numerous HTTP load testing tools available. Here is just a few: wrk wrk2 vegeta locust hey Apache Benchmark Problem Most of them designed to generate load on the static url, like:
This is the digest of Reactive Programming versus Reactive Systems by Jonas Bonér and Viktor Klang. This is for anyone who does not have enough time to study the original white paper. It is the shortest version without sacrificing important stuff. Reactive - A Set Of Design Principles “Reactive” is a set of design principles for creating cohesive systems. In a Reactive System, it’s the interaction between the individual parts that makes all the difference, which is the ability to operate individually yet act in concert to achieve their intended result.
In this post, I ’m going to introduce you some useful aspects of Cats library, mostly code snippets and I ’m not going to delve into any theory or mathematics. Hopefully you will use them in your daily codes, resulting in much more simpler and readable code. map using Functor You are already familiar with the prominent map method in Scala. Informally, a functor is any context with a map method.
As a software engineer, I always enjoy solving problems and that’s why I sometimes go to the coding challenge websites like hackerrank and pick one problem to solve. This time I searched in functional programming category and crosswords-101 caught my eye and I decided to solve it in Scala in a very clean and understandable way and not in a contest style way of programming! This article is going to reveal how I solved this puzzle.
Problem You want to insert a new row to a table which has auto increment primary key; Also some additional information must be persist in other tables. At the end you also want to return the inserted generated ID. Imaging you are developing a new web application, and you are working on user registration code. Each time a new user signs up, you want to store his credential in users table and all of his roles in userRoles table.
As a Java developer, I ’ve always had argument with my colleagues to use Scala instead Java. They complained that Scala is a complex language and Java is a more readable and simple one so I never had the opportunity to use Scala well. Fortunately, recently I ’ve just joined to the startup company called snapptrip.com, and we use Scala for all the backend services. A few days ago, I was working on a peace of code in Scala to register a new user into the database.
Definition of DSL A DSL is a computer language, specialized for a specific domain. A DSL is essentially the opposite of a general programming languages(GPL), I mean every language that can be used to develop something. For example, Java, C#, and Scala are all GPL languages. With a DSL, we want only to solve a specific domain problem, so we design the language specifically for the domain. A DSL can’t be used outside of the domain, because it is not designed for flexibility.
Have you ever wanted to show your work which is running on your local machine to your colleagues or friends? If they are far away of you, how will you show them? Will you upload your source code to github to share it with your friends? But what if you don’t like to share your source code with others? Will you run it on public or private cloud or something like that?
To adhere to guidelines or requirements, API designers may want to control how JSON/XML responses are formatted. Spring Web makes use of Jackson to perform JSON/XML serialization. Therefore, to customize our output format, we must configure the Jackson processor. Spring Web offers XML-based or Java-based approaches to handling configuration. In this article, we will look at the Java-based configuration. Enable XML output First of all, if you have created your project through https://start.