Merge pull request #3409 from eddumelendez/gh-3408

* pr/3409:
  Polish
  Add mail server connection check

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mail/JndiSessionConfiguration.java

-/*
- * Copyright 2012-2015 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.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.boot.autoconfigure.mail;
-
-import javax.mail.Session;
-import javax.naming.NamingException;
-
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnJndi;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.jndi.JndiLocatorDelegate;
-
-/**
- * Auto-configure a {@link Session} available on JNDI.
- *
- * @author Eddú Meléndez
- * @author Stephane Nicoll
- * @since 1.3.0
- */
-@Configuration
-@ConditionalOnClass(Session.class)
-@ConditionalOnProperty(prefix = "spring.mail", name = "jndi-name")
-@ConditionalOnJndi
-class JndiSessionConfiguration {
-
-	@Autowired
-	private MailProperties properties;
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Session session() {
-		String jndiName = this.properties.getJndiName();
-		try {
-			return new JndiLocatorDelegate().lookup(jndiName, Session.class);
-		}
-		catch (NamingException ex) {
-			throw new IllegalStateException(String.format(
-					"Unable to find Session in JNDI location %s", jndiName), ex);
-		}
-	}
-
-}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mail/MailProperties.java

@@ -67,6 +67,11 @@ public class MailProperties {
 	 */
 	private String jndiName;
 
+	/**
+	 * Test that the mail server is available on startup.
+	 */
+	private boolean testConnection;
+
 	public String getHost() {
 		return this.host;
 	}
@@ -119,4 +124,11 @@ public class MailProperties {
 		return this.jndiName;
 	}
 
+	public boolean isTestConnection() {
+		return this.testConnection;
+	}
+
+	public void setTestConnection(boolean testConnection) {
+		this.testConnection = testConnection;
+	}
 }

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mail/MailSenderAutoConfiguration.java

@@ -18,23 +18,26 @@ package org.springframework.boot.autoconfigure.mail;
 
 import java.util.Map;
 import java.util.Properties;
-
 import javax.activation.MimeType;
+import javax.annotation.PostConstruct;
+import javax.mail.MessagingException;
 import javax.mail.Session;
 import javax.mail.internet.MimeMessage;
+import javax.naming.NamingException;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.AnyNestedCondition;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnJndi;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
-import org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration.MailSenderCondition;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnSingleCandidate;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.context.annotation.Import;
+import org.springframework.jndi.JndiLocatorDelegate;
 import org.springframework.mail.MailSender;
 import org.springframework.mail.javamail.JavaMailSenderImpl;
 
@@ -48,18 +51,43 @@ import org.springframework.mail.javamail.JavaMailSenderImpl;
  */
 @Configuration
 @ConditionalOnClass({ MimeMessage.class, MimeType.class })
-@ConditionalOnMissingBean(MailSender.class)
-@Conditional(MailSenderCondition.class)
 @EnableConfigurationProperties(MailProperties.class)
-@Import(JndiSessionConfiguration.class)
 public class MailSenderAutoConfiguration {
 
-	@Autowired(required = false)
-	private Session session;
+	@Configuration
+	@ConditionalOnClass(Session.class)
+	@ConditionalOnProperty(prefix = "spring.mail", name = "jndi-name")
+	@ConditionalOnJndi
+	static class JndiSessionConfiguration {
 
 		@Autowired
 		private MailProperties properties;
 
+		@Bean
+		@ConditionalOnMissingBean
+		public Session session() {
+			String jndiName = this.properties.getJndiName();
+			try {
+				return new JndiLocatorDelegate().lookup(jndiName, Session.class);
+			}
+			catch (NamingException ex) {
+				throw new IllegalStateException(String.format(
+						"Unable to find Session in JNDI location %s", jndiName), ex);
+			}
+		}
+
+	}
+
+	@ConditionalOnMissingBean(MailSender.class)
+	@Conditional(MailSenderConfiguration.MailSenderCondition.class)
+	static class MailSenderConfiguration {
+
+		@Autowired
+		private MailProperties properties;
+
+		@Autowired(required = false)
+		private Session session;
+
 		@Bean
 		public JavaMailSenderImpl mailSender() {
 			JavaMailSenderImpl sender = new JavaMailSenderImpl();
@@ -110,5 +138,29 @@ public class MailSenderAutoConfiguration {
 			}
 
 		}
+	}
+
+	@Configuration
+	@ConditionalOnSingleCandidate(JavaMailSenderImpl.class)
+	static class MailSenderValidator {
+
+		@Autowired
+		private MailProperties properties;
+
+		@Autowired
+		private JavaMailSenderImpl mailSender;
+
+		@PostConstruct
+		public void validateConnection() {
+			if (this.properties.isTestConnection()) {
+				try {
+					this.mailSender.testConnection();
+				}
+				catch (MessagingException ex) {
+					throw new IllegalStateException("Mail server is not unavailable", ex);
+				}
+			}
+		}
+	}
 
 }

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mail/MailSenderAutoConfigurationTests.java

@@ -17,7 +17,7 @@
 package org.springframework.boot.autoconfigure.mail;
 
 import java.util.Properties;
-
+import javax.mail.MessagingException;
 import javax.mail.Session;
 import javax.naming.Context;
 import javax.naming.NamingException;
@@ -40,6 +40,10 @@ import org.springframework.mail.javamail.JavaMailSenderImpl;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 /**
  * Tests for {@link MailSenderAutoConfiguration}.
@@ -170,6 +174,22 @@ public class MailSenderAutoConfigurationTests {
 		load(EmptyConfig.class, "spring.mail.jndi-name:foo");
 	}
 
+	@Test
+	public void connectionOnStartup() throws MessagingException {
+		load(MockMailConfiguration.class, "spring.mail.host:10.0.0.23",
+				"spring.mail.test-connection:true");
+		JavaMailSenderImpl mailSender = this.context.getBean(JavaMailSenderImpl.class);
+		verify(mailSender, times(1)).testConnection();
+	}
+
+	@Test
+	public void connectionOnStartupNotCalled() throws MessagingException {
+		load(MockMailConfiguration.class, "spring.mail.host:10.0.0.23",
+				"spring.mail.test-connection:false");
+		JavaMailSenderImpl mailSender = this.context.getBean(JavaMailSenderImpl.class);
+		verify(mailSender, never()).testConnection();
+	}
+
 	private Session configureJndiSession(String name) throws IllegalStateException,
 			NamingException {
 		Properties properties = new Properties();
@@ -207,4 +227,15 @@ public class MailSenderAutoConfigurationTests {
 
 	}
 
+	@Configuration
+	static class MockMailConfiguration {
+
+		@Bean
+		JavaMailSenderImpl mockMailSender() {
+			return mock(JavaMailSenderImpl.class);
+		}
+
+	}
+
+
 }

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

@@ -519,6 +519,7 @@ content into your application; rather pick only the properties that you need.
 	spring.mail.default-encoding=UTF-8 # encoding to use for MimeMessages
 	spring.mail.properties.*= # properties to set on the JavaMail session
 	spring.mail.jndi-name= # JNDI location of a Mail Session
+	spring.mail.test-connection=false # Test that the mail server is available on startup
 
 	# SPRING BATCH ({sc-spring-boot-autoconfigure}/batch/BatchProperties.{sc-ext}[BatchProperties])
 	spring.batch.job.names=job1,job2