Articles Tagged ‘architecture’

Managing Architecture Decision Records with ADR-Tools

Sunday, May 27th, 2018

Every software project includes a set of architecture decisions defining boundaries and constraints for further design and implementation.

It’s important to document those decisions somehow or else a development team might not know which decisions where made and with which assumptions.

Or they know the decision but are missing the context and the consequences and therefore decisions are blindly accepted or blindly changed.

In the following short tutorial I will show how to structure architecture decisions in so called Architecture Decision Records and how to manage them with a simple tool named ADR-Tools.

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Software Architecture Exploration and Validation with jqAssistant, Neo4j and Cypher

Sunday, December 31st, 2017

I have written about other software system analyzing and validation tools before but today I would like to introduce a new tool named jqAssistant that supports software architects, developers and analysts in a variety of tasks like analyzing given structures, validating architectural or quality constraints and generating reports.

Therefore jqAssistant analyzes given projects or artifacts and stores the gathered information – that is enriched by a variety of existing plugin-ins – in a Neo4j graph database.

This graph database may now be used to enforce architectural constraints or specific code metrics, to generate reports or to analyze a system with a nice browser interface.

In this tutorial I’m going to show how to integrate jqAssistant in an existing project using Maven as build-tool, how to explore an existing system step-by-step and finally how to enforce specific metrics by writing them down as a kind of living documentation in an AsciiDoc document.

I have also started to write down basic Cypher (the query language used) queries to analyze a system and other queries to gather basic metrics.

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Assuring Architectural Rules with ArchUnit

Monday, July 3rd, 2017

Maintaining architecture rules and constraints for a specific software project or an application is not easy as textual documentation is easily forgotten after a while and hard to verify.

ArchUnit is a testing library that allows developers and software architects to write down such rules as executable tests that may be run by the development teams and the integration servers.

In the following article I will demonstrate the basic features of this library by applying rules and constraints to an existing application.

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Resilient Architecture in Practice – Circuit Breakers for Java: Failsafe, Javaslang, Hystrix and Vert.x

Tuesday, February 14th, 2017

When dealing with remote services or APIs there is always the risk of latency issues, failures or connection losses. The worst thing to happen is when the remote service is down and our application hangs until the underlying protocol’s (e.g. TCP) connection timeout is reached and we’re receiving an exception. Until this moment is reached, our application might hang, memory is allocated for threads or bound objects and at last, our continuous requests might prevent the remote system from recovering.

We might use timeouts here but circuit-breakers take this approach one step further: A potential failing, critical or dangerous operation is encapsulated with a circuit breaker tracking failures and when a specified threshold is reached it tripping the breaker.  Now all calls to the API fail immediately and the  system does not even try to communicate with the failing remote system or the isolated API.
This avoids  flooding a  dead remote system with requests and allocating memory and system resources for waiting threads etc. and is also a good mechanism and  integration point to track business-critical errors.

In the following tutorial I’m going to demonstrate four different circuit-breaker implementations for Java forced to interact with a failing API.

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