การติดตามแบบกระจายด้วย Sleuth และ Zipkin

In microservices, a single user request often travels through many different services. This makes it hard to follow the request's journey!

Distributed tracing is a technique that helps you track the path of a request as it moves across various services in your system.

Without tracing, debugging issues in microservices is like finding a needle in a haystack. You don't know which service failed or where the delay occurred.

• Debugging: Pinpoint errors faster.
• Performance: Identify bottlenecks in the request flow.
• Visibility: Understand how services interact.

Spring Cloud Sleuth integrates with Spring applications to automatically add tracing information to requests and logs.

It injects unique identifiers into HTTP headers and logging contexts, allowing you to link related operations across services.

Sleuth uses two main IDs:

• Trace ID: A unique ID for the entire request, from start to finish, across all services it touches.
• Span ID: A unique ID for a single operation or unit of work within a service (e.g., an HTTP request or a method call). Spans form a tree structure within a trace.

To enable Sleuth in your Spring Boot application, add the spring-cloud-starter-sleuth dependency to your pom.xml (Maven) or build.gradle (Gradle).

For Maven:

For Gradle:

While Sleuth adds tracing info, you need a way to collect and visualize it. That's where Zipkin comes in!

Zipkin is a distributed tracing system that collects and stores trace data, then provides a web UI to search and view these traces.

The easiest way to get Zipkin running locally is using Docker. This command pulls the Zipkin image and starts it on port 9411.

You can then access the Zipkin UI at http://localhost:9411 in your browser.

Once Zipkin is running, tell your Sleuth-enabled Spring Boot application where to send its trace data. Add this to your application.properties or application.yml.

application.properties:

Now, your application will send trace data to the local Zipkin server.

Let's see how a simple Spring Boot service logs trace IDs. With Sleuth, your logs will automatically include [appName,traceId,spanId,exportable].

Run this simple app, then make a request to /hello. Check the console logs for the added IDs.

You've learned how distributed tracing helps in microservices, especially with Spring Cloud Sleuth and Zipkin.

• Sleuth: Integrates with Spring apps to inject traceId and spanId.
• Zipkin: Collects these traces and provides a UI for visualization and analysis.

These tools are crucial for understanding and debugging complex distributed systems.