Allows overriding of the default logging pattern

fixes gh-1863

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/autoconfig/TraceEnvironmentPostProcessor.java

@@ -49,14 +49,25 @@ public class TraceEnvironmentPostProcessor implements EnvironmentPostProcessor {
 		Map<String, Object> map = new HashMap<String, Object>();
 		// This doesn't work with all logging systems but it's a useful default so you see
 		// traces in logs without having to configure it.
-		if (Boolean
-				.parseBoolean(environment.getProperty("spring.sleuth.enabled", "true"))) {
+		if (sleuthEnabled(environment)
+				&& sleuthDefaultLoggingPatternEnabled(environment)) {
 			map.put("logging.pattern.level", "%5p [${spring.zipkin.service.name:"
 					+ "${spring.application.name:}},%X{X-B3-TraceId:-},%X{X-B3-SpanId:-},%X{X-Span-Export:-}]");
 		}
 		addOrReplace(environment.getPropertySources(), map);
 	}
 
+	private boolean sleuthEnabled(ConfigurableEnvironment environment) {
+		return Boolean
+				.parseBoolean(environment.getProperty("spring.sleuth.enabled", "true"));
+	}
+
+	private boolean sleuthDefaultLoggingPatternEnabled(
+			ConfigurableEnvironment environment) {
+		return Boolean.parseBoolean(environment
+				.getProperty("spring.sleuth.default-logging-pattern-enabled", "true"));
+	}
+
 	private void addOrReplace(MutablePropertySources propertySources,
 			Map<String, Object> map) {
 		MapPropertySource target = null;

spring-cloud-sleuth-core/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -77,6 +77,12 @@
       "type": "java.lang.Boolean",
       "description": "Enable tracing of RPC.",
       "defaultValue": true
+    },
+    {
+      "name": "spring.sleuth.default-logging-pattern-enabled",
+      "type": "java.lang.Boolean",
+      "description": "Enable setting of a default logging pattern.",
+      "defaultValue": true
     }
   ]
 }

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/autoconfig/TraceEnvironmentPostProcessorTests.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2013-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.sleuth.autoconfig;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.mock.env.MockEnvironment;
+
+import static org.assertj.core.api.BDDAssertions.then;
+
+class TraceEnvironmentPostProcessorTests {
+
+	MockEnvironment mockEnvironment = new MockEnvironment();
+
+	TraceEnvironmentPostProcessor processor = new TraceEnvironmentPostProcessor();
+
+	@Test
+	void should_add_logging_pattern_when_not_disabled_explicitly() {
+
+		this.processor.postProcessEnvironment(this.mockEnvironment, null);
+
+		then(this.mockEnvironment.getProperty("logging.pattern.level")).isNotBlank();
+	}
+
+	@Test
+	void should_not_add_logging_pattern_when_sleuth_disabled() {
+		this.mockEnvironment.setProperty("spring.sleuth.enabled", "false");
+
+		this.processor.postProcessEnvironment(this.mockEnvironment, null);
+
+		then(this.mockEnvironment.getProperty("logging.pattern.level")).isBlank();
+
+	}
+
+	@Test
+	void should_not_add_logging_pattern_when_sleuth_default_logging_pattern_disabled() {
+		this.mockEnvironment.setProperty("spring.sleuth.default-logging-pattern-enabled",
+				"false");
+
+		this.processor.postProcessEnvironment(this.mockEnvironment, null);
+
+		then(this.mockEnvironment.getProperty("logging.pattern.level")).isBlank();
+	}
+
+}