Home » Author Archives: Biju Kunjummen

Author Archives: Biju Kunjummen

Spring Cloud Ribbon – Making a secured call

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Something simple, but I struggled with this recently – I had to make a Netflix Ribbon based client call to a secured remote service. It turns out there are two ways to do this using Netflix Ribbon, I will demonstrate this through Spring Cloud’s excellent support for Ribbon library. In two previous blog posts I have touched on Spring Cloud ...

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JWT – Generating and validating a token – Samples

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JWT provides a very interesting way to represent claims between applications that can be verified and trusted. My objective here is to show a small sample to generate and validate a token using the excellent Nimbus JOSE + JWT library. Overview One of the best places to get an intro is here. In brief, to borrow from the material from ...

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Spring Cloud Rest Client with Netflix Ribbon – Basics

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In an earlier blog post I had covered the different options for a REST client in the Spring Cloud world. All the options wrap around a Netflix OSS based component called Ribbon which handles the aspects related to loadbalancing the calls across different instances hosting a service, handling failovers, timeouts etc. Here I will cover a few ways to customize ...

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Spring Cloud support for Hystrix

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Spring Cloud project provides comprehensive support for Netflix OSS Hystrix library. I have previously written about how to use the raw Hystrix library to wrap remote calls. Here I will be going over how Hystrix can be used with Spring Cloud Basics There is actually nothing much to it, the concepts just carry over with certain Spring boot specific enhancements. ...

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Gentle Introduction to Hystrix – Wrapup

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This is a follow up to two other posts – Motivation for why something like Hystrix is needed in a distributed systems and a basic intro to Hystrix. This will be a wrap of my Hystrix journey with details of various properties that can be tweaked to change the behavior of Hystrix and will touch on a few advanced concepts ...

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Gentle Introduction to Hystrix – Hello World

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In a previous blog post I had covered the motivation for needing a library like Netflix Hystrix. Here I will jump into some of the very basic ways to start using Hystrix and follow it up with more complex use cases. Hello World A simple Hello World example of a “Hystrix Command” is the following: import com.netflix.hystrix.HystrixCommand; import com.netflix.hystrix.HystrixCommandGroupKey; import ...

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Scala extractors infix sample with Rational numbers

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I keep coming back to the awesome introductory material on Scala put together by Daniel Westheide. One of the examples that he provides for extractors using an infix operation pattern is the Streams API – val xs = 58 #:: 43 #:: 93 #:: Stream.empty xs match {   case first #:: second #:: _ => first - second   ...

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Gentle Introduction to Hystrix

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In the last few days I have been exploring the Netflix Hystrix library and have come to appreciate the features provided by this excellent library. To quote from the Hystrix site: Hystrix is a latency and fault tolerance library designed to isolate points of access to remote systems, services and 3rd party libraries, stop cascading failure and enable resilience in ...

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Spring Cloud Sidecar – Initialization of Nodes

spring-interview-questions-answers

In the last blog post I had described how the Sidecar application can be used for registering the Cassandra nodes with Eureka and more generally can be used for registering any non-JVM application with Eureka. In this post I will cover how an application can go about querying the Sidecar registered nodes. Discovering Registered Nodes – Post Initialization If the ...

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Spring Cloud Sidecar

spring-interview-questions-answers

I have an application deployed to a NetflixOSS based cloud which has a structure along these lines: Essentially a service which persists information to a Cassandra cluster. All the applications are registered to Eureka – so in this instance the service as well as the Cassandra nodes are registered with Eureka, further the service connects to the Cassandra cluster by ...

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