Distributed tracing gives you insight into how a particular service is performing as part of the whole in a distributed software system. It tracks and records requests from their point of origin to their destination and the systems through which they pass.
Let’s first take a look at some basic terms in distributed tracing.
The "span" is the primary building block of a distributed trace, representing an individual unit of work done in a distributed system.
The collection of Spans that have the same root is considered to create a group called trace.
- Git
- JDK 17
- Apache Maven
Execute the docker-compose and then execute all services (email-service, user-service and report-service)
# Start kafka, kafka-ui, zookeeper, jaeger and sleuth
docker-compose up -d
# Clean and compile all projects
mvn clean install
# Runing user-service
cd user-service
mvn spring-boot:run
# Runing email-service
cd email-service
mvn spring-boot:run
# Runing report-service
cd email-service
mvn spring-boot:run- OpenTelemetry: also known as OTel for short, is an open source observability framework with ready-to-use implementations to enable the effective creation and collection of telemetry data (metrics, logs, and traces) and to forward them to external tools.
- Spring Cloud Sleuth: is a project managed and maintained by Spring Cloud team that provides Spring Boot autoconfiguration for distributed tracing.
- Jaeger: is an open source project with end-to-end distributed tracing to Monitor and troubleshoot transactions in complex distributed systems
- Maven: Build and dependency control
- H2 Database: is a relational database management system written in Java. It can be embedded in Java applications or run in client-server mode. The software is available as open source software Mozilla
- Actuator: is mainly used to expose operational information about the running application — health, metrics, info, dump, env, etc.
Let’s design three Spring Boot microservices:
user-service: a simple user CRUD service. In addition to persisting data to its database, it providing HTTP API to calls the backend report service via REST API calls.report-service: a simple report CRUD service, it providing HTTP API to the user-service and also publishes events to Kafka when generating a new report record.email-service: Providing KafkaConsumer, listening to the topic reports.
Figure 1: System design architecture for this project
Using a monorepo, we have the project structure as follows:
Figure 2: Project structure using monorepo
Figure 3: Jacoco report-service test coverage
Figure 4: Jacoco user-service test coverage
Figure 5: Jacoco email-service test coverage