如何使 fluent-logger-java 在 springboot 中与 logback appender 一起工作

Question

我正在尝试将 fluent-logger-java 与带有 logback appender 的 springboot 项目集成。而且我可以使用https://github.com/fluent/fluent-logger-java中给出的示例代码将数据发送到流利的聚合器@

但是当作为 logback appender 添加时，它会抛出 NullPointerException。 我尝试使用来自https://mvnrepository.com/artifact/com.sndyuk/logback-more-appenders/1.4.3 的 logback-more-appenders。 但它没有从应用程序发送任何数据。

要重现此问题，请使用默认值从 https://start.spring.io/ 生成一个简单的 Web 项目。

将 src\main\java\com\example\demo\FluentLogbackAppender.java 添加到项目中

package com.example.demo;
import java.util.HashMap;
import java.util.Map;
import org.fluentd.logger.FluentLogger;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.UnsynchronizedAppenderBase;

public class FluentLogbackAppender extends UnsynchronizedAppenderBase<ILoggingEvent> {
    private FluentLogger fluentLogger;
    private String label = "test";

    @Override
    public void start() {
        super.start();
        this.fluentLogger = FluentLogger.getLogger(label, "localhost", 24224);
        Map<String, Object> data = new HashMap<String, Object>();
        data.put("msg", "Starting App");
        fluentLogger.log(label, data);
    }

    @Override
    protected void append(ILoggingEvent rawData) {
        String msg = rawData.toString();
        Map<String, Object> data = new HashMap<String, Object>(1);
        data.put("msg", msg);
        fluentLogger.log(label, data);
    }

    @Override
    public void stop() {
        super.stop();
        fluentLogger.close();
    }
}

将 src\main\resources\logback.xml 添加到项目中

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE logback>
<configuration>
    <include resource="org/springframework/boot/logging/logback/base.xml"/>
    <appender name="fluent" class="com.example.demo.FluentLogbackAppender"/>
    <root level="info" additivity="false">
        <appender-ref ref="fluent" />
    </root>
</configuration>

在 pom.xml 中添加依赖

<dependency>
    <groupId>org.fluentd</groupId>
    <artifactId>fluent-logger</artifactId>
    <version>0.3.3</version>
</dependency>

为了简单起见，我删除了一些代码。 运行此程序时，我会看到

2018-05-22 14:39:42.190 ERROR 18788 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Logback configuration error detected:
ERROR in ch.qos.logback.core.joran.spi.Interpreter@5:77 - RuntimeException in Action for tag [appender] java.lang.NullPointerException
        at org.springframework.boot.logging.logback.LogbackLoggingSystem.loadConfiguration(LogbackLoggingSystem.java:166)
        at org.springframework.boot.logging.logback.LogbackLoggingSystem.reinitialize(LogbackLoggingSystem.java:212)
        at org.springframework.boot.logging.AbstractLoggingSystem.initializeWithConventions(AbstractLoggingSystem.java:75)
        at org.springframework.boot.logging.AbstractLoggingSystem.initialize(AbstractLoggingSystem.java:60)
        at org.springframework.boot.logging.logback.LogbackLoggingSystem.initialize(LogbackLoggingSystem.java:114)
        at org.springframework.boot.context.logging.LoggingApplicationListener.initializeSystem(LoggingApplicationListener.java:264)
        at org.springframework.boot.context.logging.LoggingApplicationListener.initialize(LoggingApplicationListener.java:237)
        at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationEnvironmentPreparedEvent(LoggingApplicationListener.java:200)
        at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationEvent(LoggingApplicationListener.java:173)
        at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
        at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
        at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
        at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:127)
        at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:74)
        at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54)
        at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:358)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:317)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243)
        at com.example.demo.DemoApplication.main(DemoApplication.java:10)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)

NullPointerException 从 FluentLogger 类中的 sender.emit() 返回。 有趣的是，这段代码实际上是在崩溃前将数据推送到 fluentd 聚合器。 有什么办法可以做到这一点。

Answer 1

我猜，你没有在这里粘贴完整的代码。我认为您的班级可能有标签字段的getter，setter。如果是这样，那么您的 logback 配置丢失 <tag>test</tag> 这可能是原因（仍然猜测）。 FluentLogger 有很多未解决的问题，他们建议使用 fluent 客户端库将数据刷新到 fluentd。

一些参考资料 - https://github.com/fluent/fluent-logger-java/issues/72

https://github.com/sndyuk/logback-more-appenders/blob/master/src/main/java/ch/qos/logback/more/appenders/FluencyLogbackAppender.java

https://github.com/komamitsu/fluency