Add spans for cache

src/main/java/org/springframework/samples/petclinic/system/AddSpansToCache.java

@@ -0,0 +1,57 @@
+package org.springframework.samples.petclinic.system;
+
+import brave.Span;
+import brave.Span.Kind;
+import brave.Tracer;
+import org.aspectj.lang.ProceedingJoinPoint;
+import org.aspectj.lang.annotation.Around;
+import org.aspectj.lang.annotation.Aspect;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+@Aspect
+// Ordering is needed to be executed before cache interceptor
+@Order(1)
+@Component
+public class AddSpansToCache {
+
+	@Value("${petclinic.outboudExternalService.serviceType:ehcache}")
+	String serviceType;
+
+	@Value("${petclinic.outboudExternalService.ApplicationName:Cache}")
+	String applicationName;
+
+	@Value("${petclinic.inboudExternalService.ComponentName:ehcache}")
+	String componentName;
+
+	final Tracer tracer;
+
+	public AddSpansToCache(Tracer tracer) {
+		this.tracer = tracer;
+	}
+
+	@Around("@annotation(org.springframework.cache.annotation.Cacheable)")
+	public Object AddSpan(ProceedingJoinPoint joinpoint) throws Throwable {
+
+		String joinPointName = joinpoint.getSignature().toString();
+		Span newSpan = this.tracer.nextSpan().name(joinPointName).start();
+
+		newSpan.kind(Kind.CLIENT);
+		newSpan.tag("_outboundExternalService", serviceType);
+		newSpan.tag("_externalApplication", applicationName);
+		newSpan.tag("_externalComponent", componentName);
+		try {
+			return joinpoint.proceed();
+		}
+		catch (RuntimeException | Error e) {
+			newSpan.error(e);
+			throw e;
+		}
+		finally {
+			newSpan.finish();
+		}
+
+	}
+
+}