All Posts

2023

Event-Carried State Transfer Integration in Microservices

Good or Bad?

2022

Re-designing a Leaky Microservice Integration

Embracing Behavioural Coupling

Read Models Spanning Microservices’ Boundaries

Or glorified data caches

Event Sourcing — Oops, wrong Aggregate Boundary

How I shared streams to split an aggregate and why.

Sagas — Part 4: Design Considerations

Order of Steps, Failures and Overlapping Sagas

Leaky Event-Based Microservices’ Integration

When Events are Passive-Aggressive Commands

Sagas — Part 3: Choreography Instead?

When to Choose Choreography

Sagas — Part 2: Sagas in Distributed Systems

What’s a Saga? and Sagas vs Process Managers

Sagas — Part 1: An Introduction

Orchestration and Sagas

Re-designing an Aggregation Microservice — Part 3

Re-designing an Aggregation Microservice — Part 1 Re-designing an Aggregation Microservice — Part 2

Event Sourcing: Event Versioning - Dont's

In Event Sourcing, events have a considerably longer active life within an application. Entire event streams, from the oldest event captured to the newest, a...

Re-designing an Aggregation Microservice — Part 2

In the first post in this series, I introduced the current design of the reporting service. And discussed some of the issues with that design. I ended the po...

Re-designing an Aggregation Microservice — Part 1

I was involved in a recent discussion regarding how to improve a reporting microservice that aggregates data from numerous services. There were several issue...

2019

Re-implementing the Outbox Pattern in MongoDB

I have blogged previously about how we implemented the Outbox pattern on top of SQL Server and Websphere MQ to avoid distributed transactions/two-phase commi...

2018

Reference Data in Microservices

My current client has a requirement to provide access to reference data in the form of holidays by country, currency holidays and banking information such as...

Event-Based Microservices Integration

I have seen numerous service integration patterns down the years that, in my opinion, have a myriad of issues that make it increasingly difficult to work wit...

2017

Data Aggregation and Streaming

I was involved in a discussion at my current client recently regarding how to improve a service that aggregates data from several other services for, let’s s...

Lessons Learned

As a freelancer, I have worked with numerous teams, different cultures, distinct personalities and varying experience levels and in different capacities incl...

2016

DTC-Enforced Constraints

There are numerous blogs and talks out there about why you should or should not use distributed transaction coordinators (DTC) and they cover a myriad of top...

Individuals and their Interactions

In this post, I would like to share my recent experience in a project that failed miserably, mainly due to negligence of the “Individuals and their Interacti...

Avoiding Distributed Transactions - Outbox Pattern

I’m currently architecting a payment system for domestic payments for a UK bank. This is a greenfield system that is going to consist of a few microservices....

2015

Planning and Estimations are a waste

I have just come out of a planning meeting that I thought was a complete waste of time. We spent a full hour trying to estimate roughly how many days a numbe...

Eventual Consistency is a Business Concern

Eventual consistency is an important concept in distributed systems as it allows you to scale considerably and improves your systems’ availability and robust...

Scalability and SOA - Part 3 (UI Composition)

In part 2, I briefly covered Event-Driven SOA and why event messages are preferred for communication between services. I also stated that data should not lea...

Use IOC Containers Judiciously

IOC containers are a great way to manage dependencies and their lifetimes. They have concise, fluent syntax and help keep all dependency configurations neatl...

Scalability and SOA - Part 2 (Event-Driven SOA)

In the previous post in this series, I wrote about scaling up vs out, why we chose scaling out and why layered service models are not the answer. In this pos...

2014

Scalability and SOA - Part 1

In this series of posts, I will go through the challenges experienced developing a highly scalable and highly available SaaS product using a Service Oriented...