This repository contains the source code of the practical use case described in the book Learn Microservices with Spring Boot 3 (3rd Edition). The book follows a pragmatic approach to building a Microservice Architecture. You start with a small monolith and examine the pros and cons that come with a move to microservices.

The Chapter 8's source code is divided into four parts for a better understanding of how the system evolves when we start introducing Common Patterns of Microservice Architectures.

In this last part, we introduce Centralized Logs, Distributed Tracing, and Containerization with Docker and Docker Compose.

The figure below shows a high-level overview of the final version of our system.

The main concepts included in this last part of the chapter are:

• Why do we need Centralized Logs and Distributed tracing?
• Why would I create Docker images for my applications?
• Building a simple logger application with Spring Boot and RocketMQ.
• Distributed traces with OpenTelemetry.
• Sentinel flow control and circuit breaker control for Spring Cloud Gateway.
• Building Docker images for Spring Boot applications with Cloud Native Buildpacks.
• Container Platforms, Application Platforms, and Cloud Services.

As usual, the book follows a hands-on approach, so you learn everything based on this microservice case study.

This time, you can use Docker to start the complete system. If you're interested in the instructions to run the components manually, check the previous version of the repository.

If you don't want to build the images yourself, these images are already in the Docker Hub. You can run the complete system using the docker-compose-public.yml file:

docker$ docker-compose -f docker-compose-public.yml up

In case you want to learn how to build the images, keep reading the instructions below.

First, build the application images with:

multiplication$ docker build -t  multiplication:0.0.1-SNAPSHOT .
gamification$ docker build -t  gamification:0.0.1-SNAPSHOT .
gateway$ docker build -t  gateway:0.0.1-SNAPSHOT .
logs$ docker build -t  logs:0.0.1-SNAPSHOT .

And the UI server (first you have to build it with npm run build):

challenges-frontend$ npm install
challenges-frontend$ npm run build
challenges-frontend$ docker build -t challenges-frontend:1.0 .

change brokerIP1 to your docker hosts IP in docker\config\rocketmq\broker.cnf

brokerIP1=<192.168.71.47>

Once you have all the images ready, run:

docker$ docker-compose up

Go into the docker container and execute the following commands

docker exec -it <nameserver> bash
bin/mqadmin updateTopic -n localhost:9876 -c DefaultCluster -t attempts-topic -a +message.type=FIFO
bin/mqadmin updateTopic -n localhost:9876 -c DefaultCluster -t logs           -a +message.type=FIFO

change kibana_system password to changeme

docker exec -it <elasticsearch> bash
/usr/share/elasticsearch/bin/elasticsearch-reset-password -i -u kibana_system

and It now uses opentelemetry collector contrib to collect metrics to prometheus and traces to zipkin/jaeger/elasticsearch and logs to loki/elasticsearch, and grafana can be used to view loki logs, elasticsearch logs/traces, and prometheus metrics

Front End: http://localhost:3000
Grafana: http://localhost:3001/grafana
Prometheus http://localhost:9090
Nacos: http://localhost:8082  (nacos/nacos)
Sentinel Dashboard: http://localhost:8858 (sentinel/sentinel)
Kibana: http://localhost:5601

See the figure below for a diagram showing the container view.

Once the backend and the frontend are started, you can navigate to http://localhost:3000 in your browser and start resolving multiplication challenges.

After the system is up and running, you can quickly scale up and down instances of both Multiplication and Gamification services. For example, you can run:

docker$ docker-compose up --scale multiplication=2 --scale gamification=2

And you'll get two instances of each of these services with proper Load Balancing and Service Discovery.

• Do you have questions about how to make this application work?
• Did you get the book and have questions about any concept explained within this chapter?
• Have you found issues using updated dependencies?

Don't hesitate to create an issue in this repository and post your question/problem there.

Are you interested in building a microservice architecture from scratch? You'll face all the challenges of designing and implementing a distributed system one by one, and will be able to evaluate if it's the best choice for your project.

You can buy the book online from these stores:

• Apress
• Amazon and other online stores.