skywalking-java/docs/en/setup/service-agent/java-agent/Application-toolkit-logback-1.x.md

logback plugin

• Dependency the toolkit, such as using maven or gradle

    <dependency>
         <groupId>org.apache.skywalking</groupId>
         <artifactId>apm-toolkit-logback-1.x</artifactId>
         <version>{project.release.version}</version>
     </dependency>

Print trace ID in your logs

• set %tid in Pattern section of logback.xml

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
            <layout class="org.apache.skywalking.apm.toolkit.log.logback.v1.x.TraceIdPatternLogbackLayout">
                <Pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%tid] [%thread] %-5level %logger{36} -%msg%n</Pattern>
            </layout>
        </encoder>
    </appender>

• with the MDC, set %X{tid} in Pattern section of logback.xml

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
            <layout class="org.apache.skywalking.apm.toolkit.log.logback.v1.x.mdc.TraceIdMDCPatternLogbackLayout">
                <Pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%X{tid}] [%thread] %-5level %logger{36} -%msg%n</Pattern>
            </layout>
        </encoder>
    </appender>

• Support logback AsyncAppender(MDC also support), No additional configuration is required. Refer to the demo of logback.xml below. For details: Logback AsyncAppender

    <configuration scan="true" scanPeriod=" 5 seconds">
        <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
            <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
                <layout class="org.apache.skywalking.apm.toolkit.log.logback.v1.x.mdc.TraceIdMDCPatternLogbackLayout">
                    <Pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%X{tid}] [%thread] %-5level %logger{36} -%msg%n</Pattern>
                </layout>
            </encoder>
        </appender>
    
        <appender name="ASYNC" class="ch.qos.logback.classic.AsyncAppender">
            <discardingThreshold>0</discardingThreshold>
            <queueSize>1024</queueSize>
            <neverBlock>true</neverBlock>
            <appender-ref ref="STDOUT"/>
        </appender>
    
        <root level="INFO">
            <appender-ref ref="ASYNC"/>
        </root>
    </configuration>

• When you use -javaagent to active the sky-walking tracer, logback will output traceId, if it existed. If the tracer is inactive, the output will be TID: N/A.

logstash logback plugin

• Dependency the toolkit, such as using maven or gradle

<dependency>
    <groupId>org.apache.skywalking</groupId>
    <artifactId>apm-toolkit-logback-1.x</artifactId>
    <version>${skywalking.version}</version>
</dependency>

• set LogstashEncoder of logback.xml

<encoder charset="UTF-8" class="net.logstash.logback.encoder.LogstashEncoder">
    <provider class="org.apache.skywalking.apm.toolkit.log.logback.v1.x.logstash.TraceIdJsonProvider">
    </provider>
</encoder>

• set LoggingEventCompositeJsonEncoder of logstash in logback-spring.xml for custom json format

1.add converter for %tid as child of node

<!--add converter for %tid -->
    <conversionRule conversionWord="tid" converterClass="org.apache.skywalking.apm.toolkit.log.logback.v1.x.LogbackPatternConverter"/>

2.add json encoder for custom json format

<encoder class="net.logstash.logback.encoder.LoggingEventCompositeJsonEncoder">
            <providers>
                <timestamp>
                    <timeZone>UTC</timeZone>
                </timestamp>
                <pattern>
                    <pattern>
                        {
                        "level": "%level",
                        "tid": "%tid",
                        "thread": "%thread",
                        "class": "%logger{1.}:%L",
                        "message": "%message",
                        "stackTrace": "%exception{10}"
                        }
                    </pattern>
                </pattern>
            </providers>
</encoder>

gRPC reporter

The gRPC report could forward the collected logs to SkyWalking OAP server, or SkyWalking Satellite sidecar. Trace id, segment id, and span id will attach to logs automatically. You don't need to change the layout.

• Add GRPCLogClientAppender in logback.xml

    <appender name="grpc-log" class="org.apache.skywalking.apm.toolkit.log.logback.v1.x.log.GRPCLogClientAppender"/>

• Add config of the plugin or use default

plugin.toolkit.log.grpc.reporter.server_host=${SW_GRPC_LOG_SERVER_HOST:127.0.0.1}
plugin.toolkit.log.grpc.reporter.server_port=${SW_GRPC_LOG_SERVER_PORT:11800}
plugin.toolkit.log.grpc.reporter.max_message_size=${SW_GRPC_LOG_MAX_MESSAGE_SIZE:10485760}
plugin.toolkit.log.grpc.reporter.upstream_timeout=${SW_GRPC_LOG_GRPC_UPSTREAM_TIMEOUT:30}