// the find
spring-attic/spring-cloud-sleuth
Distributed tracing for spring cloud
Spring Cloud Sleuth was the standard distributed tracing library for Spring Boot 2.x applications, auto-configuring trace/span propagation across HTTP, messaging, and async boundaries. It is dead — the project was EOL'd in 2022, the last supported version is 3.1.x, and it does not work with Spring Boot 3.x. If you're on Spring Boot 3, you want Micrometer Tracing instead.
The abstraction layer separating the Sleuth API from tracer implementations (Brave, OpenTelemetry) was well-designed — you could swap backends without touching application code. Auto-instrumentation coverage was broad: RestTemplate, WebClient, Feign, Kafka, RabbitMQ, gRPC, and async executors all got trace propagation out of the box with zero configuration. The baggage propagation API for passing custom key-value pairs across service boundaries was clean and actually worked across thread boundaries. The JMH benchmark suite in the repo is a rare find — you can see the actual overhead numbers rather than guessing.
This repo is archived and actively warns you not to use it on Spring Boot 3 — adopting it now is a dead end requiring a migration to Micrometer Tracing. The migration isn't trivial: baggage APIs, span customization hooks, and several auto-configurations changed in ways that require code changes, not just dependency swaps. The documentation URLs in the README point to docs.spring.io pages that no longer exist for active development. Stars and recent pushes are misleading here — the repo stays alive only because old Spring Boot 2.x projects haven't migrated yet, not because it's maintained.