Redirecting feign & ribbon logs to log4j2

Question

I currently use spring cloud netflix with log4j2. The log4j2 configuration comes from the xml in the classpath. When I run the app, I see that the feign & ribbon logs are not being redirected to the logger specified in the configuration. I have configured log for com.netflix.ribbon & feign packages to be logged at debug level.

However, log configured for spring is properly redirecting to the specified appender, ribbon & feign are not.

I am using gradle with spring-boot-starter-logging ignored & added spring-boot-starter-log4j2 in as part of my build.

I see that feign has a way by which we can configure slf4j, but since we use annotation driven feign support, I cant configure the feign to use slf4j for logging.

Any help is appreciated.

My log4j2.xml looks some what like

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <Properties>
        <Property name="log-path">logs</Property>
        <Property name="log-fileName">test</Property>
    </Properties>

    <Appenders>
        <Console name="console-log" target="SYSTEM_OUT">
            <PatternLayout pattern="[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n" />
        </Console>

        <RollingFile name="trace-log" fileName="${log-path}/${log-fileName}-trace.log" filePattern="${log-path}/${log-fileName}_trace-%d{yyyy-MM-dd}.log">
            <PatternLayout pattern="[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n" />
            <Policies>
                <TimeBasedTriggeringPolicy interval="1" modulate="true" />
            </Policies>
        </RollingFile>

        <RollingFile name="error-log" fileName="${log-path}/${log-fileName}-error.log" filePattern="${log-path}/${log-fileName}_error-%d{yyyy-MM-dd}.log">
            <PatternLayout pattern="[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n" />
            <Policies>
                <TimeBasedTriggeringPolicy interval="1" modulate="true" />
            </Policies>
        </RollingFile>
    </Appenders>

    <Loggers>
        <logger name="org.springframework" level="trace" additivity="false">
            <AppenderRef ref="trace-log" />
        </logger>
        <logger name="feign" level="trace" additivity="false">
            <AppenderRef ref="trace-log" />
        </logger>
        <logger name="com.netflix.ribbon" level="trace" additivity="false">
            <AppenderRef ref="trace-log" />
        </logger>
        <Root level="info">
            <AppenderRef ref="console-log"></AppenderRef>
            <AppenderRef ref="error-log" level="ERROR"/>
        </Root>
    </Loggers>
</Configuration>

PS: The reason for debugging feign/ribbon is to understand a weird feign behavior between two different machines in our micro services setup

Answer 1

Looking at Spring Cloud's FeignClientFactoryBean shows that you can optionally autowire a bean of type feign.Logger.Level. Try registering such a bean in your @Configurationusing

@Bean
public feign.Logger.Level feignLoggerLevel() {
    return feign.Logger.Level.FULL;
}

Answer 2

@jensfischerhh's answer would fix many cases but looks mistakenly missed one thig.

You need to config feign generated class's logger level with feignLoggerLevel Bean.

Both config must be exist together.

related doccument in spring-cloud-netflix

bean config ( in @Configuration annotated class )

@Bean
public feign.Logger.Level feignLoggerLevel() {
    return feign.Logger.Level.FULL;
}  

log config

</Configuration>
    <Loggers>
        <logger name="your.feign-interface-package" level="trace">
    </Loggers>
</Configuration>