Polish "Add Kafka Kerberos Configuration Properties"

Closes gh-9151

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/kafka/KafkaAutoConfiguration.java

@@ -40,6 +40,7 @@ import org.springframework.kafka.support.ProducerListener;
  * {@link EnableAutoConfiguration Auto-configuration} for Apache Kafka.
  *
  * @author Gary Russell
+ * @author Stephane Nicoll
  * @since 1.5.0
  */
 @Configuration
@@ -88,7 +89,7 @@ public class KafkaAutoConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(name = "spring.kafka.jaas.enabled")
-	@ConditionalOnMissingBean(KafkaJaasLoginModuleInitializer.class)
+	@ConditionalOnMissingBean
 	public KafkaJaasLoginModuleInitializer kafkaJaasInitializer() throws IOException {
 		KafkaJaasLoginModuleInitializer jaas = new KafkaJaasLoginModuleInitializer();
 		Jaas jaasProperties = this.properties.getJaas();

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/kafka/KafkaProperties.java

@@ -793,16 +793,16 @@ public class KafkaProperties {
 		/**
 		 * Login module.
 		 */
-		private String loginModule;
+		private String loginModule = "com.sun.security.auth.module.Krb5LoginModule";
 
 		/**
-		 * AppConfigurationEntry.LoginModuleControlFlag value.
+		 * Control flag for login configuration.
 		 */
 		private KafkaJaasLoginModuleInitializer.ControlFlag controlFlag =
 				KafkaJaasLoginModuleInitializer.ControlFlag.REQUIRED;
 
 		/**
-		 * Map of JAAS options, e.g. 'spring.kafka.jaas.options.useKeyTab=true'.
+		 * Additional JAAS options.
 		 */
 		private final Map<String, String> options = new HashMap<>();
 

spring-boot-autoconfigure/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -325,6 +325,10 @@
     "description": "Log a warning for transactions executed without a single enlisted resource.",
     "defaultValue": true
   },
+  {
+    "name": "spring.kafka.jaas.control-flag",
+    "defaultValue": "required"
+  },
   {
     "name": "spring.mobile.devicedelegatingviewresolver.enabled",
     "type": "java.lang.Boolean",

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/kafka/KafkaAutoConfigurationTests.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,6 +43,7 @@ import org.springframework.kafka.listener.AbstractMessageListenerContainer.AckMo
 import org.springframework.kafka.security.jaas.KafkaJaasLoginModuleInitializer;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
 
 /**
  * Tests for {@link KafkaAutoConfiguration}.
@@ -163,7 +164,8 @@ public class KafkaAutoConfigurationTests {
 		assertThat(configs.get(ProducerConfig.RETRIES_CONFIG)).isEqualTo(2);
 		assertThat(configs.get(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG))
 				.isEqualTo(IntegerSerializer.class);
-		assertThat(this.context.containsBean("kafkaJaasInitializer")).isFalse();
+		assertThat(this.context.getBeansOfType(KafkaJaasLoginModuleInitializer.class))
+				.isEmpty();
 	}
 
 	@Test
@@ -197,13 +199,16 @@ public class KafkaAutoConfigurationTests {
 		assertThat(dfa.getPropertyValue("concurrency")).isEqualTo(3);
 		assertThat(dfa.getPropertyValue("containerProperties.pollTimeout"))
 				.isEqualTo(2000L);
-		assertThat(this.context.containsBean("kafkaJaasInitializer")).isTrue();
-		KafkaJaasLoginModuleInitializer jaas = this.context.getBean(KafkaJaasLoginModuleInitializer.class);
+		assertThat(this.context.getBeansOfType(KafkaJaasLoginModuleInitializer.class))
+				.hasSize(1);
+		KafkaJaasLoginModuleInitializer jaas = this.context.getBean(
+				KafkaJaasLoginModuleInitializer.class);
 		dfa = new DirectFieldAccessor(jaas);
 		assertThat(dfa.getPropertyValue("loginModule")).isEqualTo("foo");
 		assertThat(dfa.getPropertyValue("controlFlag"))
 				.isEqualTo(AppConfigurationEntry.LoginModuleControlFlag.REQUISITE);
-		assertThat(((Map<?, ?>) dfa.getPropertyValue("options")).get("useKeyTab")).isEqualTo("true");
+		assertThat(((Map<String, String>) dfa.getPropertyValue("options")))
+				.containsExactly(entry("useKeyTab", "true"));
 	}
 
 	private void load(String... environment) {

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -942,10 +942,10 @@ content into your application; rather pick only the properties that you need.
 	spring.kafka.consumer.key-deserializer= # Deserializer class for keys.
 	spring.kafka.consumer.max-poll-records= # Maximum number of records returned in a single call to poll().
 	spring.kafka.consumer.value-deserializer= # Deserializer class for values.
-	spring.kafka.jaas.control-flag=REQUIRED # AppConfigurationEntry.LoginModuleControlFlag value.
+	spring.kafka.jaas.control-flag=required # Control flag for login configuration.
 	spring.kafka.jaas.enabled= # Enable JAAS configuration.
 	spring.kafka.jaas.login-module=com.sun.security.auth.module.Krb5LoginModule # Login module.
-	spring.kafka.jaas.options= # Map of JAAS options, e.g. 'spring.kafka.jaas.options.useKeyTab=true'.
+	spring.kafka.jaas.options= # Additional JAAS options.
 	spring.kafka.listener.ack-count= # Number of records between offset commits when ackMode is "COUNT" or "COUNT_TIME".
 	spring.kafka.listener.ack-mode= # Listener AckMode; see the spring-kafka documentation.
 	spring.kafka.listener.ack-time= # Time in milliseconds between offset commits when ackMode is "TIME" or "COUNT_TIME".