[KAFKA-7155] the property CONFIG of the ProducerConfig maybe null.

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 1.1.0
• Component/s: clients
• Environment: scala 2.12.6 ; kafka 1.1.0 ; log4j2 2.11.0
• Assignee: Unassigned
• Reporter: zhangjk
• Created: 12/Jul/18 10:53
• Updated: 12/Jul/18 10:53

Description

hi:

When i use the log4j2's KafkaAppender , I found a bug.  the property CONFIG of the ProducerConfig.

here's my code:

log4j2.xml
<Appenders>
    <Kafka name="Kafka" topic="test" key ="KafkaTestKey">
        <PatternLayout pattern="%d{yyyy.MM.dd 'at' HH:mm:ss z} %-5level %class{36} %L %M - %msg%xEx%n"/>
        <Property name="bootstrap.servers">localhost:9092</Property>
    </Kafka>
</Appenders>

object KafkaTest extends App {
  val p = new Producer
}

class Producer {
  val props = {
    val p = new Properties()
    ....
    p
  }

  val producer = {
    val p = new KafkaProducer[Integer, String](props)
    p
  }
}

The reason for this BUG is that: 

the `new Producer` is first initialized, and the `ProducerConfig` has a static method block, and it called the `CommonClientConfigs` class. in the `CommonClientConfigs`,  it has a Log property,

so, this will initialize the Log4j2's configuration, and this will call a startup method of the Appender, and it actually calls the KafkaAppender's method. and then the method create a new `KafkaProducer`, this will create a new `ProducerConfig` instance, but the static method block is not completed, so the `CONFIG` is null.  this cause the `NullPointerException`

 

my english is bad, so , hope to understand what i mean