Logging in a Spring Boot app with OpenTelemetry

Question

Using Spring Boot 3.4.2, I want to configure logs export in opentelemetry format with Spring Actuator configuration. Example properties:

management.otlp.logging.export.enabled=true
management.otlp.logging.endpoint=http://localhost:4318/v1/logs
management.otlp.logging.headers.apikey=apikey
management.otlp.logging.transport=http
management.otlp.logging.compression=gzip

Tried adding maven dependencies:

<dependency>    
    <groupId>io.opentelemetry.instrumentation</groupId>   
    <artifactId>opentelemetry-spring-boot-starter</artifactId>
    <version>2.12.0</version>
</dependency>

<dependency>    
    <groupId>io.opentelemetry</groupId>    
    <artifactId>opentelemetry-exporter-otlp</artifactId> 
    <version>${opentelemetry.version}</version>
</dependency>

<dependency>    
    <groupId>io.opentelemetry.instrumentation</groupId>   
    <artifactId>opentelemetry-logback-appender-1.0</artifactId>    
    <version>1.28.0-alpha</version>
</dependency>

logback.xml example:

<configuration scan="true" scanPeriod="30 seconds">

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{"yyyy-MM-dd'T'HH:mm:ss.SSSXXX", UTC} [%thread] %-5level %logger{36} - %msg %replace(%replace(%ex){'[\r\n]+', ''}){'[\t]+', '&#10;&#9;'}%nopex%n</pattern>
        </encoder>
    </appender>

    <appender name="otel" class="io.opentelemetry.instrumentation.logback.appender.v1_0.OpenTelemetryAppender">
        <captureExperimentalAttributes>true</captureExperimentalAttributes>
        <captureKeyValuePairAttributes>true</captureKeyValuePairAttributes>
    </appender>

    <root level="INFO">
        <appender-ref ref="STDOUT" />
        <appender-ref ref="otel" />
    </root>
</configuration>

But noting worked or configuration is not set into OtlpHttpLogRecordExporter. What else needs to be configured or what I'm doing wrong?

Have you tried to look into their examples repository (for Java) here: github.com/open-telemetry/opentelemetry-java-examples/tree/main ? Especially this one for Spring with starter: github.com/open-telemetry/opentelemetry-java-examples/tree/main/… — Dmitriy
– Dmitriy, Commented Feb 19 at 11:39

Vincent Meunier · Accepted Answer · 2025-08-26 12:42:28Z

Apparently the only thing that I found missing in your example after hours of searching is :

you need to configure the OpenTelemetryAppender and invoke the "install" method with the OpenTelemetry bean which would have been auto-configured by SpringBoot.

For that I coded a BeanPostProcessor :

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.instrumentation.logback.appender.v1_0.OpenTelemetryAppender;

public class OpenTelemetryAppenderBeanPostProcessor implements BeanPostProcessor {

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof OpenTelemetry openTelemetry) {
            OpenTelemetryAppender.install(openTelemetry);
        }
        return bean;
    }
}

And I use it in some class that is annoted with @Configuration :

@Bean
static OpenTelemetryAppenderBeanPostProcessor openTelemetryBeanPostProcessor() {
    return new OpenTelemetryAppenderBeanPostProcessor();
}

After that I'm able to see the logs coming into LOKI

Hope this helps

Edit : I found this documentation after answering : https://docs.spring.io/spring-boot/reference/actuator/loggers.html#actuator.loggers.opentelemetry
It shows an example of how to call the "install" method, it's different from mine.

Jose Luis · Accepted Answer · 2025-09-26 12:23:52Z

0

have you tried defining this bean:

@Component
@RequiredArgsConstructor
public class OpenTelemetryAppenderInitializer implements InitializingBean {

  private final OpenTelemetry openTelemetry;

  @Override
  public void afterPropertiesSet() {
   OpenTelemetryAppender.install(this.openTelemetry);
  }

}

answered Sep 26 at 12:23

Jose Luis

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