When to use shared libraries in Microservices architecture

One of the advantages of Microservices architecture is that it enables components to have deployment independence. Based on my consulting and software development experience deployment independence is often overlooked and very few teams achieve it. Deployment independence is important since it brings true agility and reduces communication overhead between different teams and services. 

Shared libraries make Microservices tightly coupled and introduce hard dependencies. Since, now a team making a change has to ensure that it does not break another service that depends on the shared library. This requires communication between multiple teams. Also, change in a shared library leads to all the services that depend on it to be redeployed.  This leads to long build, release, and deployment times. We might have to consider the deployment order of services as well. All this leads to more synchronization and communication between teams. So, it is recommended that in Microservices architecture teams should avoid using shared libraries. 

Continue reading “When to use shared libraries in Microservices architecture”

Service Discovery for Modern Distributed Applications

I am starting a new blog series (with no end date) from today. In this series, I will pick a topic and go in-depth so that I don’t just scratch the surface of the topic. The goal is to build a habit of learning each week and share it with the community. For the next few months, I will write on different aspects of building distributed systems. Each Wednesday, you may expect a new post.

I am sure we all have built applications where one application uses another application to do its job. Most of the time, applications communicate with each other using HTTP REST API but it can be other communication mechanisms like gRPC, Thrift, Message Queues as well. For example, if you are building an application that needs Twitter service for fetching tweets. To call Twitter API, you will need the API URL and access keys to make a successful API call. Most often we rely on static configuration either in the form of a configuration file or environment variable to get the API URL. This approach works fine when you are working with third party APIs like Twitter as their API URLs do not change often. The static configuration approach fails when we build a Microservices architecture based application. The definition of Microservices that I like is by Martin Fowler as described in his blog,

Microservice architecture style is an approach to developing a single application as a suite of small services, each running its own process and communicating with lightweight mechanisms, often an HTTP resource API.

Continue reading “Service Discovery for Modern Distributed Applications”