Handle unknown exception on authorization check

[rdhabalia]

Motivation

Right now, topic/PartitionMetadata lookup gives 401(unauthorized) error-code instead of 500(internalServerError) even if request fails with unknown-exception (eg. zk_session is not available). It may lead incorrect error-handling at client side.

Modifications

Return 500 if request fails with unknown exception.

Result

Broker returns correct error-code on lookup failure.

[merlimat]

@rdhabalia It seems there are some genuine test failures :

Tests run: 527, Failures: 6, Errors: 0, Skipped: 0, Time elapsed: 1,062.603 sec <<< FAILURE! - in TestSuite
socketTest(com.yahoo.pulsar.websocket.proxy.ProxyPublishConsumeTest)  Time elapsed: 10.098 sec  <<< FAILURE!
org.testng.internal.thread.ThreadTimeoutException: Method org.testng.internal.TestNGMethod.socketTest() didn't finish within the time-out 10000
	at com.yahoo.pulsar.websocket.proxy.ProxyPublishConsumeTest.socketTest(ProxyPublishConsumeTest.java:102)
testInternalServerExceptionOnLookup(com.yahoo.pulsar.client.api.AuthenticatedProducerConsumerTest)  Time elapsed: 0.109 sec  <<< FAILURE!
java.lang.AssertionError
	at com.yahoo.pulsar.client.api.AuthenticatedProducerConsumerTest.testInternalServerExceptionOnLookup(AuthenticatedProducerConsumerTest.java:228)
testMultipleBrokerDifferentClusterLookup(com.yahoo.pulsar.client.api.BrokerServiceLookupTest)  Time elapsed: 0.215 sec  <<< FAILURE!
com.yahoo.pulsar.client.api.PulsarClientException$LookupException: com.yahoo.pulsar.client.api.PulsarClientException: Authorization failed null on cluster persistent://my-property2/use2/my-ns/my-topic1 with error null
testMultipleBrokerLookup(com.yahoo.pulsar.client.api.BrokerServiceLookupTest)  Time elapsed: 57.306 sec  <<< FAILURE!
com.yahoo.pulsar.client.api.PulsarClientException: java.util.concurrent.CompletionException: com.yahoo.pulsar.client.api.PulsarClientException$LookupException: java.lang.NullPointerException
Caused by: java.util.concurrent.CompletionException: com.yahoo.pulsar.client.api.PulsarClientException$LookupException: java.lang.NullPointerException
Caused by: com.yahoo.pulsar.client.api.PulsarClientException$LookupException: java.lang.NullPointerException
testPartitionTopicLookup(com.yahoo.pulsar.client.api.BrokerServiceLookupTest)  Time elapsed: 62.131 sec  <<< FAILURE!
com.yahoo.pulsar.client.api.PulsarClientException: java.util.concurrent.CompletionException: com.yahoo.pulsar.client.api.PulsarClientException$LookupException: java.lang.NullPointerException
Caused by: java.util.concurrent.CompletionException: com.yahoo.pulsar.client.api.PulsarClientException$LookupException: java.lang.NullPointerException
Caused by: com.yahoo.pulsar.client.api.PulsarClientException$LookupException: java.lang.NullPointerException
testWebserviceServiceTls(com.yahoo.pulsar.client.api.BrokerServiceLookupTest)  Time elapsed: 0.357 sec  <<< FAILURE!
javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
	at com.yahoo.pulsar.client.api.BrokerServiceLookupTest.testWebserviceServiceTls(BrokerServiceLookupTest.java:421)

[rdhabalia]

yes, looking into it.