Open Credo

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Object Graph Mapping / GraphConnect videos
Kafka Connect – Source Connectors: A detailed guide to connecting to what you love.

July 30, 2019 | Blog, Kafka

Kafka Connect – Source Connectors: A detailed guide to connecting to what you love.

Writing your own Kafka source connectors with Kafka Connect. In this blog, Rufus takes you on a code walk, through the Gold Verified Venafi Connector while pointing out the common pitfalls

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Heuristics for Identifying Service Boundaries

May 16, 2018 | Microservices

Heuristics for Identifying Service Boundaries

To identify service boundaries, it is not enough to consider (business) domains only. Other forces like organisational communication structures, and – very important – time, strongly suggest that we should include several other criteria in our considerations.

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Fargate As An Enabler For Serverless Continuous Delivery

February 14, 2018 | Cloud

Fargate As An Enabler For Serverless Continuous Delivery

AWS Announced a few new products for use with containers at RE:Invent 2017 and of particular interest to me was a new Elastic Container Service(ECS) Launch type, called Fargate

Prior to Fargate, when it came to creating a continuous delivery pipeline in AWS, the use of containers through ECS in its standard form, was the closest you could get to an always up, hands off, managed style of setup. Traditionally ECS has allowed you to create a configured pool of “worker” instances, with it then acting as a scheduler, provisioning containers on those instances.

 

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Data Analytics using Cassandra and Spark

March 23, 2017 | Cassandra, Data Analysis, Data Engineering

Data Analytics using Cassandra and Spark

In recent years, Cassandra has become one of the most widely used NoSQL databases: many of our clients use Cassandra for a variety of different purposes. This is no accident as it is a great datastore with nice scalability and performance characteristics.

However, adopting Cassandra as a single, one size fits all database has several downsides. The partitioned/distributed data storage model makes it difficult (and often very inefficient) to do certain types of queries or data analytics that are much more straightforward in a relational database.

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Key Takeaways from the DevOps Enterprise Summit (#DOES16) EU Conference

July 3, 2016 | DevOps

Key Takeaways from the DevOps Enterprise Summit (#DOES16) EU Conference

Several of us from the OpenCredo team were in attendance at the inaugural EU edition of the DevOps Enterprise Summit conference. We have been big fans of the two previous US versions, and have watched the video recordings of talks (2014, 2015) with keen interest as many of our DevOps transformation clients are very much operating in the ‘enterprise’ space.

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The Destructor Pattern

June 3, 2016 | Software Consultancy

The Destructor Pattern

Complexity warning

In this post, I’m going to take something extremely simple, unfold it into something disconcertingly complex, and then fold it back into something relatively simple again. The exercise isn’t entirely empty: in the process, we’ll derive a more powerful (because more generic) version of the extremely simple thing we started with. I’m describing the overall shape of the journey now, because programmers who don’t love complexity for its own sake often find the initial “unfolding” stage objectionable, and then have trouble regarding the eventual increase in fanciness as worth the struggle.

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The Concursus Programming Model: Kotlin

April 29, 2016 | Software Consultancy

The Concursus Programming Model: Kotlin

In this post, I’ll demonstrate an alternative API which uses some of the advanced language features of the new Kotlin language from Jetbrains. As Kotlin is a JVM-based language, it interoperates seamlessly with Concursus’s Java 8 classes; however, it also offers powerful ways to extend their functionality.

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The Concursus Programming Model: Under the Hood

April 29, 2016 | Software Consultancy

The Concursus Programming Model: Under the Hood

In the previous two posts (part 1, and part 2), we looked at how Concursus uses method mapping to generate events from method calls on proxies, and to dispatch events to matching methods on event handlers and state class instances. This approach provides a concise, convenient client API to the Concursus event system; however the core of the system defines events and event-handling mechanisms without reference to any of the reflection-based machinery used to implement this API. It is perfectly possible (if comparatively cumbersome) to use a Concursus event store to read and write events without using reflection. In this post I’ll show how this is done, continuing with the “lightbulb” example introduced previously.

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The Concursus Programming Model: Events

April 27, 2016 | Software Consultancy

The Concursus Programming Model: Events

Concursus is an open source Java 8 framework for building distributed systems using CQRS and event sourcing patterns. One of its major differences from other such frameworks (such as Jdon, Axon and ES4J) is that it eschews a programming model where each event type is represented by a separate Java class, instead mapping event types to methods on interfaces.

 

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Easy API Simulation with Hoverfly JUnit Rule

March 17, 2016 | Software Consultancy

Easy API Simulation with Hoverfly JUnit Rule

In order to be able to regularly release an application, your automated tests must be set up to give you fast and reliable feedback loop. If bugs are only found during a long and expensive multi-service or end-to-end test run, it can be a hinderance to fast delivery. Unfortunately I have often seen this problem in development environments: a huge suite of clunky, flaky and slow end-to-end tests which test the full functionality of the application as opposed to being more lightweight and reflecting basic user journeys. This produces the “ice cream cone” anti-pattern of test coverage, where unit tests aren’t providing the kind of coverage and feedback they need to.

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Kotlin: a new JVM language you should try

March 3, 2016 | Software Consultancy

Kotlin: a new JVM language you should try

JetBrains (the people behind IntelliJ IDEA) have recently announced  the first RC for version 1.0 of Kotlin, a new programming language for the JVM. I say ‘new’, but Kotlin has been in the making for a few years now, and has been used by JetBrains to develop several of their products, including Intellij IDEA. The company open-sourced Kotlin in 2011, and have worked with the community since then to make the language what it is today.

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Is it Time for Your ‘Microservices Checkup’?

March 2, 2016 | DevOps, Microservices

Is it Time for Your ‘Microservices Checkup’?

Many of our clients are currently implementing applications using a ‘microservice’-based architecture. Increasingly we are hearing from organisations that are part way through a migration to microservices, and they want our help with validating and improving their current solution. These ‘microservices checkup’ projects have revealed some interesting patterns, and because we have experience of working in a wide-range of industries (and also have ‘fresh eyes’ when looking at a project), we are often able to work alongside teams to make significant improvements and create a strategic roadmap for future improvements.

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[Past event] London Mesos User Group Meetup!

Join us at London Mesos User Group Meetup on the 11th of May! Duedil has provided us with a venue, where the meetup will kick off at 6:30pm with usual beers, pizza and socialising. Andrew Randall from Project Calico will present his talk ‘Real-world Container Networking: the Gotchas!’ at 7pm. Andy will explore the evolution from port […]

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Hazelcast and Spring-managed Transactions: A Sample Integration

January 26, 2016 | Data Engineering

Hazelcast and Spring-managed Transactions: A Sample Integration

In this second post about Hazelcast and Spring, I’m integrating Hazelcast and Spring-managed transaction for a specific use case: A transactional Queue. More specifically, I want to make the message polling, of my sample chat application, transactional.

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Akka Typed brings type safety to Akka framework

January 18, 2016 | Software Consultancy

Akka Typed brings type safety to Akka framework

Last time in this series I summarised all the Akka Persistence related improvements in Akka 2.4. Since then Akka 2.4.1 has been released with some additional bug fixes and improvements so perhaps now is a perfect time to pick up this mini-series and introduce some other new features included in Akka 2.4.x.

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The Business Behind Microservices (Redux)

November 24, 2015 | DevOps, Microservices

The Business Behind Microservices (Redux)

It was once again a privilege to present at the annual ‘muCon 2015‘ microservices conference held in London (at the shiny new Skillsmatter CodeNode venue). Based on feedback fro talks I gave earlier in the year, I presented a completely new version of my ‘The Business Behind Microservices‘ talk, which focuses on the organisational and people side of implementing a microservice-based application.

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Implementing HAL hypermedia REST API using Spring HATEOAS

November 1, 2015 | Microservices

Implementing HAL hypermedia REST API using Spring HATEOAS

To use or not to use hypermedia (HATEOAS) in a REST API, to attain the Level 3 of the famous Richardson Maturity Model. This is one of the most discussed subjects about API design.
The many objections make sense (“Why I hate HATEOAS“, “More objections to HATEOAS“…)
. The goal of having fully dynamic, auto-discovering clients is still unrealistic (…waiting for AI client libraries).

However, there are good examples of successful HATEOAS API. Among them, PayPal.

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What’s new in Akka Persistence 2.4

October 28, 2015 | Software Consultancy

What’s new in Akka Persistence 2.4

Let’s have a quick look at the most interesting changes and new features that are now available to Akka users. As there are many new features to highlight in the new Akka release I will focus on those related to Akka Persistence first and cover other areas in a separate post.

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The Business Behind Microservices Webinar (Video and Slides)

September 24, 2015 | Microservices

The Business Behind Microservices Webinar (Video and Slides)

Unless you’ve been living under a (COBOL-based) rock for the last few years, you will have no doubt heard of the emerging trend of microservices. This approach to developing ‘loosely coupled service-oriented architecture with bounded contexts’ has captured the hearts and minds of many developers. The promise of easier enforcement of good architectural and design principles, such as encapsulation and interface segregation, combined with the availability to experiment with different languages and platforms for each service, is a (developer) match made in heaven.

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Software Circus: Thinking Fast and Slow with Software Development

September 13, 2015 | DevOps

Software Circus: Thinking Fast and Slow with Software Development

Making Good Decisions within Software

Last week I was privileged to be able to present my “Thinking Fast and Slow with Software Development” talk at the inaugural Software Circus conference in Amsterdam. The conference was amazing, and I’ll write more about this later, but in this post I was keen to share the presentation slides and the thinking behind this talk…

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New Tricks With Dynamic Proxies In Java 8 (part 3)

August 18, 2015 | Software Consultancy

New Tricks With Dynamic Proxies In Java 8 (part 3)

In this post, the last in the New Tricks With Dynamic Proxies series (see part 1 and part 2), I’m going to look at using dynamic proxies to create bean-like value objects to represent records. The basic idea here is to have some untyped storage for a collection of property values, such as an array of Objects, and a typed wrapper around that storage which provides a convenient and type-safe access mechanism. A dynamic proxy is used to convert calls on getter and setter methods in the wrapper interface into calls which read and write values in the store.

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Designing a REST API with fine-grained resources, HATEOAS and HAL

August 12, 2015 | Microservices

Designing a REST API with fine-grained resources, HATEOAS and HAL

Over the last few months one of my main projects at OpenCredo has involved creating various microservices which are interacted with via REST. We’ve been working with a relatively rich domain model, which in turn has presented a lot of challenges in how to design our various resources. This blog post aims to summarise various techniques and practices which I’ve found helpful in overcoming these challenges.

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GOTO London 2015 “Agile, Lean and Rugged”

July 28, 2015 | Microservices

Documenting REST APIs – a tooling review

Recently I co-presented a talk at Goto Amsterdam on lessons learnt whilst developing with a Microservices architecture; one being the importance of defining and documenting your API contracts as early as possible in the development cycle. During the talk I mentioned a few API documentation tools that I’d used and, based on feedback and questions from attendees, I realised that this topic merited a blog post. So, the purpose of this is to introduce 5 tools which help with designing, testing and documenting APIs.

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October 23, 2014 | Cassandra

Spring Data Cassandra Overview

Spring Data Cassandra (SDC) is a community project under the Spring Data (SD) umbrella that provides convenient and familiar APIs to work with Apache Cassandra.

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Experiences with Spring Boot

February 24, 2014 | Cloud Native, Microservices

Experiences with Spring Boot

Last year some of us attended the London Spring eXchange where we encountered a new and interesting tool that Pivotal was working on: Spring Boot. Since then we had the opportunity to see what it’s capable of in a live project and we were deeply impressed.

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Excerpt from OpenCredo-authored book Neo4J in action
Spring Data Hadoop – Objective Overview

June 30, 2013 | Software Consultancy

Spring Data Hadoop – Objective Overview

Spring Data Hadoop (SDH) is a Spring offshoot project that allows the invocation and configuration of Hadoop tasks within a Spring application context. It offers support for Hadoop jobs, HBase, Pig, Hive, Cascading and additionally JSR-223 scripting for job preparation and tidy-up.

It is most suited for use in organisations with existing Spring applications or investment in Spring expertise. Some SDH features replicate functionality of tools in the Hadoop ecosystem that DevOps engineers who maintain a Hadoop cluster will be more familiar with.

 

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Model Matters: Graphs, Neo4j and the Future

February 25, 2013 | Neo4j

Model Matters: Graphs, Neo4j and the Future

As part of our work, we often help our customers choose the right datastore for a project. There are usually a number of considerations involved in that process, such as performance, scalability, the expected size of the data set, and the suitability of the data model to the problem at hand.

This blog post is about my experience with graph database technologies, specifically Neo4j. I would like to share some thoughts on when Neo4j is a good fit but also what challenges Neo4j faces now and in the near future.

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Esper Extensions – Implementing Custom Aggregation Function

March 21, 2012 | Software Consultancy

Esper Extensions – Implementing Custom Aggregation Function

Event processing Language (EPL) enables us to write complex queries to get the most out of our event stream in real time, using SQL-like syntax.

EPL allows us to use full power of aggregation of the high volume event stream to get required results with the minimal latency. In this blog we are going to explore some aspects of numerical aggregation of data with high precision BigDecimal values. We will also demonstrate how you can add you own aggregation function to Esper engine and use them in EPL statements.

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A Simple Introduction to Complex Event Processing – Stock Ticker End-to-End Sample

February 8, 2012 | Data Analysis, Data Engineering

A Simple Introduction to Complex Event Processing – Stock Ticker End-to-End Sample

Most of the important players in this space are large IT corporations like Oracle and IBM with their commercial (read expensive) offerings.

While most of CEP products offer some great features, it’s license model and close code policy doesn’t allow developers to play with them on pet projects, which would drive adoption and usage of CEP in every day programming.

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Aleksa Vukotic of OpenCredo to talk on Neo4J and Spring at Neo4J user group