Using Distributed Tracing With OpenTelemetry, Sleuth, Kafka, Jaeger and Spring boot

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.

Span

The "span" is the primary building block of a distributed trace, representing an individual unit of work done in a distributed system.

Trace

The collection of Spans that have the same root is considered to create a group called trace.

📐 Requirements

Git
JDK 17
Apache Maven

🚀 How to Run Local

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

📖 Local Dependencies

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.

🗼 System Design Architecture

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