Logging¶

Kafka Streams uses Simple Logging Facade for Java (SLF4J) for logging.

Among the logging frameworks supported by slf4j is Apache Log4j that is used by Apache Kafka by default.

Library Dependencies¶

Use slf4j-api and slf4j-log4j12 library dependencies in a Kafka Streams application (in build.sbt) for logging.

val slf4jVersion = "2.0.0-alpha5"
libraryDependencies += "org.slf4j" % "slf4j-api" % slf4jVersion
libraryDependencies += "org.slf4j" % "slf4j-log4j12" % slf4jVersion

log4j.properties¶

Use the following log4j.properties in src/main/resources in your Kafka Streams application's project.

log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[%d] %p %m (%c)%n

log4j.logger.org.apache.kafka.streams.processor.internals.StreamThread=ALL