Types like Properties and AutoConfiguration and internal utilities are
routinely marked public when they needn't be. This causes toil as we
have to preserve signatures even if they were made public by accident.
This deprecates the mass of types marked public to give some hope of
less undifferentiated toil in the future. Ideally, future change will
consider greatly if a type should be public or not as doing so haunts
maintainers.
* Add optional SC LoadBalancer dependency. Create TraceFeignBlockingLoadBalancerClient.
* Instrument Spring Cloud LoadBalancer in TraceFeignObjectWrapper.
* Do not use class in field in order to avoid NoClassDefFound.
fixes#1528
* Updates to latest Sampling infrastructure
Brave recently switched to an interface model for higher level sampling
like HTTP. So, `HttpSampler` -> `SamplingFunction<HttpRequest>`. Don't
worry because `HttpSampler` was retrofitted as a `SamplingFunction`.
This change moves to the higher interface, avoiding deprecated methods
and such. More interestingly, this weaves in support for `RpcTracing`,
which *finally* introduces RPC sampling the same way. Specifically, this
adds `SamplingFunction<RpcRequest>` under the same conventions as HTTP.
Most immediately, this can be used here in gRPC and Dubbo, as
autoconfiguration exists. It also works with any autoconfiguration that
isn't here, such as Armeria.
Ex. Here's a sampler that traces 100 "GetUserToken" requests per second. This
doesn't start new traces for requests to the health check service. Other
requests will use a global rate provided by the tracing component.
```java
import static brave.rpc.RpcRequestMatchers.methodEquals;
import static brave.rpc.RpcRequestMatchers.serviceEquals;
import static brave.sampler.Matchers.and;
--snip--
@Bean(name = ServerSampler.NAME)
SamplerFunction<RpcRequest> myRpcSampler() {
Matcher<RpcRequest> userAuth = and(
serviceEquals("users.UserService"),
methodEquals("GetUserToken")
);
return RpcRuleSampler.newBuilder()
.putRule(serviceEquals("grpc.health.v1.Health"), Sampler.NEVER_SAMPLE)
.putRule(userAuth, RateLimitingSampler.create(100)).build();
}
```
A running job should be wrapped in a tracing span. And if the JobDataMap for a given job is injected with tracing parameters, they will be extracted so the job will be a child span to that larger parent span.
