Book Image

Practical Microservices with Dapr and .NET

By : Davide Bedin
Book Image

Practical Microservices with Dapr and .NET

By: Davide Bedin

Overview of this book

Over the last decade, there has been a huge shift from heavily coded monolithic applications to finer, self-contained microservices. Dapr is a new, open source project by Microsoft that provides proven techniques and best practices for developing modern applications. It offers platform-agnostic features for running your applications on public cloud, on-premises, and even on edge devices. This book will help you get to grips with microservice architectures and how to manage application complexities with Dapr in no time. You'll understand how Dapr offers ease of implementation while allowing you to work with multiple languages and platforms. You'll also understand how Dapr's runtime, services, building blocks, and software development kits (SDKs) help you to simplify the creation of resilient and portable microservices. Dapr provides an event-driven runtime that supports the essential features you need to build microservices, including service invocation, state management, and publish/subscribe messaging. You'll explore all of those in addition to various other advanced features with this practical guide to learning Dapr. By the end of this book, you'll be able to write microservices easily using your choice of language or framework by implementing industry best practices to solve problems related to distributed systems.
Table of Contents (16 chapters)
1
Section 1: Introduction to Dapr
4
Section 2: Building Microservices with Dapr
10
Section 3: Deploying and Scaling Dapr Solutions

Actor lifetime, concurrency, and consistency

The Dapr actor model relies on two main components: the Dapr runtime, operating in the sidecar, and the Dapr placement service.

Placement service

The placement service is responsible for keeping a map of the Dapr instances that are capable of serving actors. Considering our example, the reservationactor-service application is an example of such a service.

Once a new instance of our new reservationactor-service Dapr application starts, it informs the placement service that it is ready to serve actors of the ReservationItemActor type.

The placement service broadcasts a map – in the form of a hash table with the hosts' information and the served actor types – to all the Dapr sidecars operating in the environment.

Thanks to the host's map being constantly updated, actors are uniformly distributed over the actor service instances.

In the Kubernetes deployment mode of Dapr, the host is a Pod (a group of...