• Dependency the toolkit, such as using maven or gradle

   <dependency>
      <groupId>org.apache.skywalking</groupId>
      <artifactId>apm-toolkit-log4j-1.x</artifactId>
      <version>{project.release.version}</version>
   </dependency>

Print trace ID in your logs

• Config a layout

log4j.appender.CONSOLE.layout=TraceIdPatternLayout

• set %T in layout.ConversionPattern ( In 2.0-2016, you should use %x, Why change? )

log4j.appender.CONSOLE.layout.ConversionPattern=%d [%T] %-5p %c{1}:%L - %m%n

• When you use -javaagent to active the sky-walking tracer, log4j will output traceId, if it existed. If the tracer is inactive, the output will be TID: N/A.

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 log4j.properties

log4j.rootLogger=INFO,CustomAppender
log4j.appender.CustomAppender=org.apache.skywalking.apm.toolkit.log.log4j.v1.x.log.GRPCLogClientAppender
log4j.appender.CustomAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.CustomAppender.layout.ConversionPattern=[%t] %-5p %c %x - %m%n

• 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}