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From Mikael Ståldal <mikael.stal...@magine.com>
Subject Re: Kafka appender expecting String but getting Byte?
Date Mon, 08 Aug 2016 08:20:06 GMT
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 <mbradsher@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.staldal@magine.com
Grev Turegatan 3  | 114 46 Stockholm, Sweden  |   www.magine.com

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