Merge pull request #41825 from famaridon

* pr/41825:
  Polish "Added documentation for configuring OpenTelemetry SDK logs"
  Added documentation for configuring OpenTelemetry SDK logs

Closes gh-41825

Author: mhalbritter

spring-boot-project/spring-boot-docs/build.gradle

@@ -83,6 +83,7 @@ dependencies {
 	implementation("io.micrometer:micrometer-tracing")
 	implementation("io.micrometer:micrometer-registry-graphite")
 	implementation("io.micrometer:micrometer-registry-jmx")
+	implementation("io.opentelemetry.instrumentation:opentelemetry-logback-appender-1.0")
 	implementation("io.projectreactor.netty:reactor-netty-http")
 	implementation("io.undertow:undertow-core")
 	implementation("jakarta.annotation:jakarta.annotation-api")

spring-boot-project/spring-boot-docs/src/docs/antora/modules/reference/pages/actuator/loggers.adoc

@@ -31,3 +31,28 @@ To configure a given logger, `POST` a partial entity to the resource's URI, as t
 ----
 
 TIP: To "`reset`" the specific level of the logger (and use the default configuration instead), you can pass a value of `null` as the `configuredLevel`.
+
+
+
+[[actuator.loggers.opentelemetry]]
+== OpenTelemetry
+By default, logging via OpenTelemetry is not configured.
+You have to provide the location of the OpenTelemetry logs endpoint to configure it:
+
+[configprops,yaml]
+----
+management:
+  otlp:
+    logging:
+      endpoint: "https://otlp.example.com:4318/v1/logs"
+----
+
+NOTE: The OpenTelemetry Logback appender and Log4j appender are not part of Spring Boot.
+For more details, see the https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/instrumentation/logback/logback-appender-1.0/library[OpenTelemetry Logback appender] or the https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/instrumentation/log4j/log4j-appender-2.17/library[OpenTelemetry Log4j2 appender] in the https://github.com/open-telemetry/opentelemetry-java-instrumentation[OpenTelemetry Java instrumentation GitHub repository].
+
+TIP: You have to configure the appender in your `logback-spring.xml` or `log4j2-spring.xml` configuration to get OpenTelemetry logging working.
+
+The `OpenTelemetryAppender` for both Logback and Log4j requires access to an `OpenTelemetry` instance to function properly.
+This instance must be set programmatically during application startup, which can be done like this:
+
+include-code::OpenTelemetryAppenderInitializer[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/actuator/loggers/opentelemetry/OpenTelemetryAppenderInitializer.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2012-2024 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.boot.docs.actuator.loggers.opentelemetry;
+
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.logback.appender.v1_0.OpenTelemetryAppender;
+
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.stereotype.Component;
+
+@Component
+class OpenTelemetryAppenderInitializer implements InitializingBean {
+
+	private final OpenTelemetry openTelemetry;
+
+	OpenTelemetryAppenderInitializer(OpenTelemetry openTelemetry) {
+		this.openTelemetry = openTelemetry;
+	}
+
+	@Override
+	public void afterPropertiesSet() {
+		OpenTelemetryAppender.install(this.openTelemetry);
+	}
+
+}

spring-boot-project/spring-boot-parent/build.gradle

@@ -159,6 +159,13 @@ bom {
 			]
 		}
 	}
+	library("OpenTelemetry Logback Appender", "2.7.0-alpha") {
+		group("io.opentelemetry.instrumentation") {
+			modules = [
+				"opentelemetry-logback-appender-1.0"
+			]
+		}
+	}
 	library("Plexus Build API", "0.0.7") {
 		group("org.sonatype.plexus") {
 			modules = [