Making Redis tracing lazy; fixes gh-1756

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/redis/TraceRedisAutoConfiguration.java

@@ -16,9 +16,15 @@
 
 package org.springframework.cloud.sleuth.instrument.redis;
 
+import java.net.SocketAddress;
+
 import brave.Tracing;
 import io.lettuce.core.resource.ClientResources;
 import io.lettuce.core.tracing.BraveTracing;
+import io.lettuce.core.tracing.TraceContext;
+import io.lettuce.core.tracing.TraceContextProvider;
+import io.lettuce.core.tracing.Tracer;
+import io.lettuce.core.tracing.TracerProvider;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
@@ -30,6 +36,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.sleuth.autoconfig.TraceAutoConfiguration;
+import org.springframework.cloud.sleuth.internal.ContextUtil;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
@@ -50,16 +57,10 @@ import org.springframework.context.annotation.Configuration;
 @EnableConfigurationProperties(TraceRedisProperties.class)
 public class TraceRedisAutoConfiguration {
 
-	@Configuration(proxyBeanMethods = false)
-	static class LettuceConfig {
-
-		@Bean
-		static TraceLettuceClientResourcesBeanPostProcessor traceLettuceClientResourcesBeanPostProcessor(
-				BeanFactory beanFactory, TraceRedisProperties traceRedisProperties) {
-			return new TraceLettuceClientResourcesBeanPostProcessor(beanFactory,
-					traceRedisProperties);
-		}
-
+	@Bean
+	static TraceLettuceClientResourcesBeanPostProcessor traceLettuceClientResourcesBeanPostProcessor(
+			BeanFactory beanFactory) {
+		return new TraceLettuceClientResourcesBeanPostProcessor(beanFactory);
 	}
 
 }
@@ -71,14 +72,8 @@ class TraceLettuceClientResourcesBeanPostProcessor implements BeanPostProcessor
 
 	private final BeanFactory beanFactory;
 
-	private final TraceRedisProperties traceRedisProperties;
-
-	private Tracing tracing;
-
-	TraceLettuceClientResourcesBeanPostProcessor(BeanFactory beanFactory,
-			TraceRedisProperties traceRedisProperties) {
+	TraceLettuceClientResourcesBeanPostProcessor(BeanFactory beanFactory) {
 		this.beanFactory = beanFactory;
-		this.traceRedisProperties = traceRedisProperties;
 	}
 
 	@Override
@@ -97,12 +92,9 @@ class TraceLettuceClientResourcesBeanPostProcessor implements BeanPostProcessor
 					log.debug(
 							"Lettuce ClientResources bean is auto-configured to enable tracing.");
 				}
-				BraveTracing lettuceTracing = BraveTracing.builder().tracing(tracing())
-						.excludeCommandArgsFromSpanTags()
-						.serviceName(traceRedisProperties.getRemoteServiceName()).build();
-				return cr.mutate().tracing(lettuceTracing).build();
+				return cr.mutate().tracing(new LazyTracing(this.beanFactory)).build();
 			}
-			if (log.isDebugEnabled()) {
+			else if (log.isDebugEnabled()) {
 				log.debug(
 						"Lettuce ClientResources bean is skipped for auto-configuration because tracing was already enabled.");
 			}
@@ -110,11 +102,171 @@ class TraceLettuceClientResourcesBeanPostProcessor implements BeanPostProcessor
 		return bean;
 	}
 
-	private Tracing tracing() {
-		if (this.tracing == null) {
-			this.tracing = this.beanFactory.getBean(Tracing.class);
+}
+
+class LazyTracing implements io.lettuce.core.tracing.Tracing {
+
+	private final BeanFactory beanFactory;
+
+	private final io.lettuce.core.tracing.Tracing noOpTracing = NoOpTracing.INSTANCE;
+
+	private BraveTracing braveTracing;
+
+	LazyTracing(BeanFactory beanFactory) {
+		this.beanFactory = beanFactory;
+	}
+
+	@Override
+	public TracerProvider getTracerProvider() {
+		if (ContextUtil.isContextUnusable(this.beanFactory)) {
+			return this.noOpTracing.getTracerProvider();
 		}
-		return this.tracing;
+		return braveTracing().getTracerProvider();
+	}
+
+	@Override
+	public TraceContextProvider initialTraceContextProvider() {
+		if (ContextUtil.isContextUnusable(this.beanFactory)) {
+			return this.noOpTracing.initialTraceContextProvider();
+		}
+		return braveTracing().initialTraceContextProvider();
+	}
+
+	@Override
+	public boolean isEnabled() {
+		if (ContextUtil.isContextUnusable(this.beanFactory)) {
+			return this.noOpTracing.isEnabled();
+		}
+		return braveTracing().isEnabled();
+	}
+
+	@Override
+	public boolean includeCommandArgsInSpanTags() {
+		if (ContextUtil.isContextUnusable(this.beanFactory)) {
+			return this.noOpTracing.includeCommandArgsInSpanTags();
+		}
+		return braveTracing().includeCommandArgsInSpanTags();
+	}
+
+	@Override
+	public Endpoint createEndpoint(SocketAddress socketAddress) {
+		if (ContextUtil.isContextUnusable(this.beanFactory)) {
+			return this.noOpTracing.createEndpoint(socketAddress);
+		}
+		return braveTracing().createEndpoint(socketAddress);
+	}
+
+	private BraveTracing braveTracing() {
+		if (this.braveTracing == null) {
+			this.braveTracing = BraveTracing.builder()
+					.tracing(this.beanFactory.getBean(Tracing.class))
+					.excludeCommandArgsFromSpanTags().serviceName(this.beanFactory
+							.getBean(TraceRedisProperties.class).getRemoteServiceName())
+					.build();
+		}
+		return this.braveTracing;
+	}
+
+}
+
+enum NoOpTracing
+		implements io.lettuce.core.tracing.Tracing, TraceContextProvider, TracerProvider {
+
+	INSTANCE;
+
+	private final Endpoint NOOP_ENDPOINT = new Endpoint() {
+	};
+
+	@Override
+	public TraceContext getTraceContext() {
+		return TraceContext.EMPTY;
+	}
+
+	@Override
+	public Tracer getTracer() {
+		return NoOpTracer.INSTANCE;
+	}
+
+	@Override
+	public TracerProvider getTracerProvider() {
+		return this;
+	}
+
+	@Override
+	public TraceContextProvider initialTraceContextProvider() {
+		return this;
+	}
+
+	@Override
+	public boolean isEnabled() {
+		return false;
+	}
+
+	@Override
+	public boolean includeCommandArgsInSpanTags() {
+		return false;
+	}
+
+	@Override
+	public Endpoint createEndpoint(SocketAddress socketAddress) {
+		return NOOP_ENDPOINT;
+	}
+
+	static class NoOpTracer extends Tracer {
+
+		static final Tracer INSTANCE = new NoOpTracer();
+
+		@Override
+		public Span nextSpan(TraceContext traceContext) {
+			return NoOpSpan.INSTANCE;
+		}
+
+		@Override
+		public Span nextSpan() {
+			return NoOpSpan.INSTANCE;
+		}
+
+	}
+
+	public static class NoOpSpan extends Tracer.Span {
+
+		static final NoOpSpan INSTANCE = new NoOpSpan();
+
+		@Override
+		public Tracer.Span start() {
+			return this;
+		}
+
+		@Override
+		public Tracer.Span name(String name) {
+			return this;
+		}
+
+		@Override
+		public Tracer.Span annotate(String value) {
+			return this;
+		}
+
+		@Override
+		public Tracer.Span tag(String key, String value) {
+			return this;
+		}
+
+		@Override
+		public Tracer.Span error(Throwable throwable) {
+			return this;
+		}
+
+		@Override
+		public Tracer.Span remoteEndpoint(
+				io.lettuce.core.tracing.Tracing.Endpoint endpoint) {
+			return this;
+		}
+
+		@Override
+		public void finish() {
+		}
+
 	}
 
 }

src/checkstyle/checkstyle-suppressions.xml

@@ -32,5 +32,6 @@
 	<suppress files=".*TraceReactorAutoConfigurationAccessorConfiguration.*" checks="LineLengthCheck"/>
 	<suppress files=".*SamplerAutoConfiguration.*" checks="HideUtilityClassConstructorCheck"/>
 	<suppress files=".*TraceReactorAutoConfiguration.*" checks="HideUtilityClassConstructorCheck"/>
+	<suppress files=".*TraceRedisAutoConfiguration.*" checks="HideUtilityClassConstructorCheck"/>
 	<suppress files=".*grpc.stubs.*" checks=".*"/>
 </suppressions>

tests/spring-cloud-sleuth-instrumentation-lettuce-tests/src/test/java/org/springframework/cloud/sleuth/instrument/redis/TraceRedisAutoConfigurationTests.java

@@ -36,7 +36,9 @@ import static org.assertj.core.api.BDDAssertions.then;
  */
 @RunWith(SpringRunner.class)
 @SpringBootTest(classes = TraceRedisAutoConfigurationTests.Config.class,
-		webEnvironment = SpringBootTest.WebEnvironment.NONE)
+		webEnvironment = SpringBootTest.WebEnvironment.NONE,
+		properties = { "spring.sleuth.redis.enabled=true",
+				"spring.sleuth.redis.remote-service-name=redis-foo" })
 public class TraceRedisAutoConfigurationTests {
 
 	@Autowired
@@ -62,19 +64,10 @@ public class TraceRedisAutoConfigurationTests {
 			return clientResources;
 		}
 
-		@Bean
-		TraceRedisProperties traceRedisProperties() {
-			TraceRedisProperties traceRedisProperties = new TraceRedisProperties();
-			traceRedisProperties.setEnabled(true);
-			traceRedisProperties.setRemoteServiceName("redis-foo");
-			return traceRedisProperties;
-		}
-
 		@Bean
 		TestTraceLettuceClientResourcesBeanPostProcessor testTraceLettuceClientResourcesBeanPostProcessor(
-				BeanFactory beanFactory, TraceRedisProperties traceRedisProperties) {
-			return new TestTraceLettuceClientResourcesBeanPostProcessor(beanFactory,
-					traceRedisProperties);
+				BeanFactory beanFactory) {
+			return new TestTraceLettuceClientResourcesBeanPostProcessor(beanFactory);
 		}
 
 	}
@@ -86,9 +79,8 @@ class TestTraceLettuceClientResourcesBeanPostProcessor
 
 	boolean tracingCalled = false;
 
-	TestTraceLettuceClientResourcesBeanPostProcessor(BeanFactory beanFactory,
-			TraceRedisProperties traceRedisProperties) {
-		super(beanFactory, traceRedisProperties);
+	TestTraceLettuceClientResourcesBeanPostProcessor(BeanFactory beanFactory) {
+		super(beanFactory);
 	}
 
 	@Override