Package brave.baggage

Class CorrelationScopeDecorator

java.lang.Object
brave.baggage.CorrelationScopeDecorator
All Implemented Interfaces:
CurrentTraceContext.ScopeDecorator
public abstract class CorrelationScopeDecorator
extends Object
implements CurrentTraceContext.ScopeDecorator
Synchronizes fields such as BaggageFields.TRACE_ID with a correlation context, such as logging through decoration of a scope. A maximum of 32 fields are supported.

Setup example: 


 import brave.baggage.CorrelationScopeConfig.SingleCorrelationField;

 // Add the field "region", so it can be used as a log expression %X{region}
 CLOUD_REGION = BaggageFields.constant("region", System.getEnv("CLOUD_REGION"));

 decorator = MDCScopeDecorator.newBuilder()
                              .add(SingleCorrelationField.create(CLOUD_REGION))
                              .build();

 // Integrate the decorator
 tracing = Tracing.newBuilder()
                  .currentTraceContext(ThreadLocalCurrentTraceContext.newBuilder()
                    .addScopeDecorator(decorator)
                    .build())
                  ...
                  .build();

 // Any scope operations (updates to the current span) apply the fields defined by the decorator.
 ScopedSpan span = tracing.tracer().startScopedSpan("encode");
 try {
   // The below log message will have %X{region} in the context!
   logger.info("Encoding the span, hope it works");
   return encoder.encode();
 } catch (RuntimeException | Error e) {
   span.error(e); // Unless you handle exceptions, you might not know the operation failed!
   throw e;
 } finally {
   span.finish();
 }
Since:
5.11
See Also:
CorrelationScopeConfig, CorrelationScopeCustomizer, BaggagePropagation