Validation inside or outside entities?

A common question I get asked, especially around a vertical slice architecture, is where does validation happen? If you’re doing DDD, you might want to put validation inside your entities. But personally, I’ve found that validation as part of an … Continue reading 

Posted in DomainDrivenDesign | 33 Comments

Cassandra: Batch Loading Without the Batch — The Nuanced Edition

My previous post on this subject has proven extraordinarily popular and I get commentary on it all the time, most of it quite good. It has however, gotten a decent number of comments from people quibbling with the nuance of the post … Continue reading 

Posted in Cassandra, Java | Leave a comment

ASP.NET, Docker and Messaging

Introduction In my last post I showed how we can debug and test a containerized ASP.NET application. In this post I want to show how messaging works for .NET vNext applications using RabbitMQ as the underlying infrastructure. At the time … Continue reading 

Posted in .NET, ASP.NET vNext, containers, docker | Comments Off

Testing and debugging a containerized ASP.NET application

Introduction In my previous post I showed in detail how a node JS application running in a Docker container can be debugged and how we can run automated tests against this application also in a container. In this post I … Continue reading 

Posted in ASP.NET vNext, containers, docker, How To, introduction | Comments Off


A couple of times a week I get a question where someone wants to know how to “failover” to a remote DC in the driver if the local Cassandra DC fails or even if there is only a couple of … Continue reading 

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Testing and Debugging a Containerized Node application

Introduction Containers in general and Docker in specific have changed the way how we think about running and deploying software quite a bit. Running an application in a container instead of directly on your computer or server has a lot … Continue reading 

Posted in containers, docker, introduction, node, tutorial | 7 Comments

Zero Downtime

Introduction This post is part of my series about Implementing a CI/CD pipeline. Please refer to this post for an introduction and a complete table of contents. First of all we need to distinguish the types of applications that we … Continue reading 

Posted in architecture, CI/CD, Micro services, patterns, practices | 2 Comments

Building a slack bot with botkit node and docker

Recently I have needed to dig deeper into node and docker.  I decided to make a slack bot (easy to do) so that the problem being solved didn’t require additional learning (making bots is fun).  I ended up finding botkit … Continue reading 

Posted in Bot, Docker, Node | 2 Comments

Are you learning Docker yet

I went to a docker meetup last week many weeks ago (just now hitting publish).  It was sort of a town hall panel discussion where four guys with loads of docker experience were fielding questions and responding from their experience. … Continue reading 

Posted in Docker | Leave a comment

Connection to Oracle From Spark

For some silly reason there is a has been a fair amount of difficulty in reading and writing to Oracle from Spark when using DataFrames. SPARK-10648 — Spark-SQL JDBC fails to set a default precision and scale when they are not defined … Continue reading 

Posted in Spark | Tagged , | Leave a comment