# Modules
* New modules: `spring-cloud-sleuth-autoconfigure`, `spring-cloud-sleuth-api`, `spring-cloud-sleuth-instrumentation`
`spring-cloud-sleuth-core` removed and changed to `spring-cloud-sleuth-instrumentation` & `spring-cloud-sleuth-api`
* Removed `spring-cloud-starter-sleuth-otel`
To add OpenTelemetry support you need to add `spring-cloud-starter-sleuth` (adds Brave by default), exclude Brave and add `spring-cloud-sleuth-otel` dependency
* Except for the tests, `spring-cloud-sleuth-autoconfigure` is the only module that can have access to `@Configuration`, `@ConfigurationProperties` classes.
Tests have been added to ensure such separation.
## Package moving
* `org.springframework.cloud.sleuth.api` -> `org.springframework.cloud.sleuth`
* `org.springframework.cloud.sleuth.brave.autoconfig` -> `org.springframework.cloud.sleuth.autoconfig.brave`
* `org.springframework.cloud.sleuth.otel.autoconfig` -> `org.springframework.cloud.sleuth.autoconfig.otel`
* `org.springframework.cloud.sleuth` -> `org.springframework.cloud.sleuth`
* Instrumentation: `org.springframework.cloud.sleuth.annotation` -> `org.springframework.cloud.sleuth.instrument.annotation`
* All the autoconfiguration classes were moved under `org.springframework.cloud/sleuth.autoconfig` package
## Global class modifications
* Any class registered as a bean is now public
## Classes
* `RateLimitingSampler` constructor changed
* Merged a lot of auto configuration classes into one (e.g. `BraveAutoConfiguration` now imports various other configurations)
* Renamed `TraceBraveAutoConfiguration` to `BraveAutoConfiguration`
* Renamed `TraceOtelAutoConfiguration` to `OtelAutoConfiguration`
* Removed all `NoOp` implementations of the API
- adds Spring Cloud Function instrumentation
- adds Operators to manually provide instrumentation for Fluxes
- introduces Manual instrumentation mode for Reactor
TODO: Documentation (will add it soon)
related gh-1684
The main arguments for these features are
* api-agnostic means to collaborate with a span
- use of annotations allows users to add to a span with no library dependency on a span api.
This allows Sleuth to change its core api less impact to user code.
* reduced surface area for basic span operations.
- without this feature one has to use the span api, which has lifecycle commands that
could be used incorrectly. By only exposing scope, tag and log functionality, users can
collaborate without accidentally breaking span lifecycle.
* collaboration with runtime generated code
- with libraries such as Spring Data / Feign the implementations of interfaces are generated
at runtime thus span wrapping of objects was tedious. Now you can provide annotations
over interfaces and arguments of those interfaces
This PR is an adoption of @Koizumi85 work started here - https://github.com/Koizumi85/spring-cloud-sleuth-annotationfixes#182
