Add Cassandra username/password properties

Allow Cassandra credentials to be specified using properties.

Fixes gh-4431
Closes gh-4432

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/cassandra/CassandraAutoConfiguration.java

@@ -55,6 +55,9 @@ public class CassandraAutoConfiguration {
 		Cluster.Builder builder = Cluster.builder()
 				.withClusterName(properties.getClusterName())
 				.withPort(properties.getPort());
+		if (properties.getUsername() != null) {
+			builder.withCredentials(properties.getUsername(), properties.getPassword());
+		}
 		if (properties.getCompression() != null) {
 			builder.withCompression(properties.getCompression());
 		}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/cassandra/CassandraProperties.java

@@ -57,6 +57,16 @@ public class CassandraProperties {
 	 */
 	private int port = ProtocolOptions.DEFAULT_PORT;
 
+	/**
+	 * Login user of the server.
+	 */
+	private String username;
+
+	/**
+	 * Login password of the server.
+	 */
+	private String password;
+
 	/**
 	 * Compression supported by the Cassandra binary protocol.
 	 */
@@ -139,6 +149,22 @@ public class CassandraProperties {
 		this.port = port;
 	}
 
+	public String getUsername() {
+		return this.username;
+	}
+
+	public void setUsername(String username) {
+		this.username = username;
+	}
+
+	public String getPassword() {
+		return this.password;
+	}
+
+	public void setPassword(String password) {
+		this.password = password;
+	}
+
 	public Compression getCompression() {
 		return this.compression;
 	}

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

@@ -476,11 +476,13 @@ content into your application; rather pick only the properties that you need.
 	spring.data.cassandra.keyspace-name= # Keyspace name to use.
 	spring.data.cassandra.load-balancing-policy= # Class name of the load balancing policy.
 	spring.data.cassandra.port= # Port of the Cassandra server.
+	spring.data.cassandra.password= # Login password of the server.
 	spring.data.cassandra.read-timeout-millis= # Socket option: read time out.
 	spring.data.cassandra.reconnection-policy= # Reconnection policy class.
 	spring.data.cassandra.retry-policy= # Class name of the retry policy.
 	spring.data.cassandra.serial-consistency-level= # Queries serial consistency level.
 	spring.data.cassandra.ssl=false # Enable SSL support.
+	spring.data.cassandra.username= # Login user of the server.
 
 	# ELASTICSEARCH ({sc-spring-boot-autoconfigure}/elasticsearch/ElasticsearchProperties.{sc-ext}[ElasticsearchProperties])
 	spring.data.elasticsearch.cluster-name=elasticsearch # Elasticsearch cluster name.