Log4j always passes the LogEvent as a byte[] to Kafka, so using the Kafka StringSerializer will not work.
You should not specify *key.serializer* or *value.serializer* in the Kafka appender config, they are automatically set to ByteArraySerializer by Log4j. I will improve the documentation on that. I think that *key.class.type* and *value.class.type *are Spring specific and thus not relevant here. On Fri, Aug 5, 2016 at 8:03 PM, Meadowlark Bradsher <mbrads...@guidewire.com > wrote: > Hello, > > I am attempting to use a kafka log appender. The topic is written to Kafka > but the appender breaks during the messaging. > > org.apache.kafka.common.errors.SerializationException: Can't convert > value of class [B to class > org.apache.kafka.common.serialization.StringSerializer > specified in value.serializer > > I had seen only one SO post about this error which seems to point to > Spring as the culprit but I am not using Spring. > > http://stackoverflow.com/questions/32368372/spring- > integration-kafka-sending-a-basic-string > > I am running this in IntelliJ without any Spring configuration. The > log4j2.xml file is as follows (with modification to the Kafka host). > > <?xml version="1.0" encoding="UTF-8"?> > <Configuration status="WARN"> > <Appenders> > <Console name="Console" target="SYSTEM_OUT"> > <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - > %msg%n"/> > </Console> > <Kafka name="Kafka" topic="log-test"> > <PatternLayout pattern="%date %message"/> > <Property name="bootstrap.servers">localhost:9092</Property> > <Property name="key.class.type">java.lang.String</Property> > <Property name="value.class.type">java.lang.String</Property> > <Property name="key.serializer">org.apache.kafka.common. > serialization.StringSerializer</Property> > <Property name="value.serializer">org.apache.kafka.common. > serialization.StringSerializer</Property> > </Kafka> > </Appenders> > <Loggers> > <Root level="DEBUG"> > <AppenderRef ref="Kafka"/> > </Root> > <Logger name="org.apache.kafka" level="INFO" > > <AppenderRef ref="Kafka"/> > </Logger> > <!-- avoid recursive logging/ haven't tried OFF yet --> > </Loggers> > </Configuration> > > > The test I am doing is > > > > private static final Logger logger = LogManager.getRootLogger(); > > logger.info("{\"f1\": \"value1\"}"); > > > > I just downloaded the source to log4j2 to see if this will help me > understand what is happening but perhaps this obvious to someone in this > community? > > > > Any pointers would be very helpful and appreciated. > > > > > > Thanks > > Meadowlark Bradsher > > > > > > > > -- [image: MagineTV] *Mikael Ståldal* Senior software developer *Magine TV* mikael.stal...@magine.com Grev Turegatan 3 | 114 46 Stockholm, Sweden | www.magine.com Privileged and/or Confidential Information may be contained in this message. If you are not the addressee indicated in this message (or responsible for delivery of the message to such a person), you may not copy or deliver this message to anyone. In such case, you should destroy this message and kindly notify the sender by reply email.
