[KAFKA-5133] Changing "connection refused" message from logging level "debug" into "warn"

• Type: Improvement
• Status: Resolved
• Priority: Critical
• Resolution: Duplicate
• Component/s: clients
• Labels: newbie
• External issue URL: https://github.com/apache/kafka/pull/2924
• Assignee: james chien
• Reporter: james chien
• Due: 27/Apr/17
• Created: 27/Apr/17 07:52
• Updated: 26/May/17 12:36
• Resolved: 26/May/17 12:36

Description

If broker is down, we supply logging message to let user know `java.net.ConnectException: Connection refused` but not should be debug message because in normal situation user may not set logging level with **INFO** or **WARN** but not **DEBUG**.

2017-04-27 15:54:47,759 DEBUG [org.apache.kafka.common.network.Selector] - Connection with localhost/127.0.0.1 disconnected
java.net.ConnectException: Connection refused
        at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
        at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
        at org.apache.kafka.common.network.PlaintextTransportLayer.finishConnect(PlaintextTransportLayer.java:50)
        at org.apache.kafka.common.network.KafkaChannel.finishConnect(KafkaChannel.java:80)
        at org.apache.kafka.common.network.Selector.pollSelectionKeys(Selector.java:339)
        at org.apache.kafka.common.network.Selector.poll(Selector.java:307)
        at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:359)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:230)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:206)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:197)
        at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.awaitMetadataUpdate(ConsumerNetworkClient.java:132)
        at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureCoordinatorReady(AbstractCoordinator.java:223)
        at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureCoordinatorReady(AbstractCoordinator.java:200)
        at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.poll(ConsumerCoordinator.java:285)
        at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:1037)
        at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1002)
        at com.kafka.Test.main(Test.java:27)