Add options for Flyway to have its own DataSource

Either set flyway.[url,user,password] or create a DataSource
@Bean and mark it @FlywayDataSource.

Fixes gh-807

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayAutoConfiguration.java

@@ -61,9 +61,13 @@ public class FlywayAutoConfiguration {
 		@Autowired
 		private ResourceLoader resourceLoader = new DefaultResourceLoader();
 
-		@Autowired
+		@Autowired(required = false)
 		private DataSource dataSource;
 
+		@Autowired(required = false)
+		@FlywayDataSource
+		private DataSource flywayDataSource;
+
 		@PostConstruct
 		public void checkLocationExists() {
 			if (this.properties.isCheckLocation()) {
@@ -83,9 +87,19 @@ public class FlywayAutoConfiguration {
 
 		@Bean(initMethod = "migrate")
 		@ConfigurationProperties(prefix = "flyway")
-		public Flyway flyway(DataSource dataSource) {
+		public Flyway flyway() {
 			Flyway flyway = new Flyway();
-			flyway.setDataSource(dataSource);
+			if (this.properties.isCreateDataSource()) {
+				flyway.setDataSource(this.properties.getUrl(), this.properties.getUser(),
+						this.properties.getPassword(), this.properties.getInitSqls()
+								.toArray(new String[0]));
+			}
+			else if (this.flywayDataSource != null) {
+				flyway.setDataSource(this.flywayDataSource);
+			}
+			else {
+				flyway.setDataSource(this.dataSource);
+			}
 			return flyway;
 		}
 

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayDataSource.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2012-2013 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.flyway;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+
+/**
+ * Qualifier annotation for a DataSource to be injected in to Flyway. If used for a second
+ * data source, the other (main) one would normally be marked as <code>@Primary</code>.
+ * 
+ * @author Dave Syer
+ */
+@Target({ ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE,
+		ElementType.ANNOTATION_TYPE })
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Qualifier
+public @interface FlywayDataSource {
+
+}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayProperties.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.autoconfigure.flyway;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 import org.flywaydb.core.Flyway;
@@ -41,6 +42,14 @@ public class FlywayProperties {
 
 	private boolean enabled = true;
 
+	private String user;
+
+	private String password;
+
+	private String url;
+
+	private List<String> initSqls = Collections.emptyList();
+
 	public void setLocations(List<String> locations) {
 		this.locations = locations;
 	}
@@ -64,4 +73,40 @@ public class FlywayProperties {
 	public void setEnabled(boolean enabled) {
 		this.enabled = enabled;
 	}
+
+	public String getUser() {
+		return this.user;
+	}
+
+	public void setUser(String user) {
+		this.user = user;
+	}
+
+	public String getPassword() {
+		return this.password == null ? "" : this.password;
+	}
+
+	public void setPassword(String password) {
+		this.password = password;
+	}
+
+	public String getUrl() {
+		return this.url;
+	}
+
+	public void setUrl(String url) {
+		this.url = url;
+	}
+
+	public List<String> getInitSqls() {
+		return this.initSqls;
+	}
+
+	public void setInitSqls(List<String> initSqls) {
+		this.initSqls = initSqls;
+	}
+
+	public boolean isCreateDataSource() {
+		return this.url != null && this.user != null;
+	}
 }

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jdbc/DataSourceBuilder.java

@@ -50,6 +50,8 @@ public class DataSourceBuilder {
 
 	private ClassLoader classLoader;
 
+	private DriverClassNameProvider driverClassNameProvider = new DriverClassNameProvider();
+
 	private Map<String, String> properties = new HashMap<String, String>();
 
 	public static DataSourceBuilder create() {
@@ -67,10 +69,19 @@ public class DataSourceBuilder {
 	public DataSource build() {
 		Class<? extends DataSource> type = getType();
 		DataSource result = BeanUtils.instantiate(type);
+		maybeGetDriverClassName();
 		bind(result);
 		return result;
 	}
 
+	private void maybeGetDriverClassName() {
+		if (!this.properties.containsKey("driverClassName")) {
+			String cls = this.driverClassNameProvider.getDriverClassName(this.properties
+					.get("url"));
+			this.properties.put("driverClassName", cls);
+		}
+	}
+
 	private void bind(DataSource result) {
 		new RelaxedDataBinder(result).bind(getPropertyValues());
 	}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/flyway/FlywayAutoConfigurationTests.java

@@ -18,6 +18,8 @@ package org.springframework.boot.autoconfigure.flyway;
 
 import java.util.Arrays;
 
+import javax.sql.DataSource;
+
 import org.flywaydb.core.Flyway;
 import org.junit.After;
 import org.junit.Before;
@@ -26,12 +28,16 @@ import org.junit.Test;
 import org.junit.rules.ExpectedException;
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration;
+import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
 import org.springframework.boot.autoconfigure.jdbc.EmbeddedDataSourceConfiguration;
 import org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration;
 import org.springframework.boot.test.EnvironmentTestUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 
 /**
  * Tests for {@link LiquibaseAutoConfiguration}.
@@ -66,6 +72,29 @@ public class FlywayAutoConfigurationTests {
 		assertEquals(0, this.context.getBeanNamesForType(Flyway.class).length);
 	}
 
+	@Test
+	public void testCreateDataSource() throws Exception {
+		EnvironmentTestUtils.addEnvironment(this.context,
+				"flyway.url:jdbc:hsqldb:mem:flywaytest", "flyway.user:sa");
+		this.context
+				.register(EmbeddedDataSourceConfiguration.class,
+						FlywayAutoConfiguration.class,
+						PropertyPlaceholderAutoConfiguration.class);
+		this.context.refresh();
+		Flyway flyway = this.context.getBean(Flyway.class);
+		assertNotNull(flyway.getDataSource());
+	}
+
+	@Test
+	public void testFlywayDataSource() throws Exception {
+		this.context.register(FlywayDataSourceConfiguration.class,
+				EmbeddedDataSourceConfiguration.class, FlywayAutoConfiguration.class,
+				PropertyPlaceholderAutoConfiguration.class);
+		this.context.refresh();
+		Flyway flyway = this.context.getBean(Flyway.class);
+		assertNotNull(flyway.getDataSource());
+	}
+
 	@Test
 	public void testDefaultFlyway() throws Exception {
 		this.context
@@ -113,4 +142,16 @@ public class FlywayAutoConfigurationTests {
 						PropertyPlaceholderAutoConfiguration.class);
 		this.context.refresh();
 	}
+
+	@Configuration
+	protected static class FlywayDataSourceConfiguration {
+
+		@FlywayDataSource
+		@Bean
+		public DataSource flywayDataSource() {
+			return DataSourceBuilder.create().url("jdbc:hsqldb:mem:flywaytest")
+					.username("sa").build();
+		}
+
+	}
 }

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

@@ -203,6 +203,9 @@ content into your application; rather pick only the properties that you need.
 	flyway.prefix=V
 	flyway.suffix=.sql
 	flyway.enabled=true
+    flyway.url= # JDBC url if you want Flyway to create its own DataSource
+    flyway.user= # JDBC username if you want Flyway to create its own DataSource
+    flyway.password= # JDBC password if you want Flyway to create its own DataSource
 
 	# LIQUIBASE ({sc-spring-boot-autoconfigure}/liquibase/LiquibaseProperties.{sc-ext}[LiquibaseProperties])
 	liquibase.change-log=classpath:/db/changelog/db.changelog-master.yaml

spring-boot-docs/src/main/asciidoc/howto.adoc

@@ -974,13 +974,13 @@ JDBC or JPA (then that one will be picked up by any `@Autowired` injections).
 	@Primary
 	@ConfigurationProperties(prefix="datasource.primary")
 	public DataSource primaryDataSource() {
-		return new FancyDataSource();
+		return DataSourceBuilder.create().build();
 	}
 
 	@Bean
 	@ConfigurationProperties(prefix="datasource.secondary")
 	public DataSource secondaryDataSource() {
-		return new FancyDataSource();
+		return DataSourceBuilder.create().build();
 	}
 ----
 
@@ -1207,6 +1207,13 @@ addition Spring Boot provides a small set of properties in
 {sc-spring-boot-autoconfigure}/flyway/FlywayProperties.{sc-ext}[`FlywayProperties`]
 that can be used to disable the migrations, or switch off the location checking.
 
+By default Flyway will autowire the (`@Primary`) `DataSource` in your context and
+use that for migrations. If you like to use a different `DataSource` you can create
+one and mark its `@Bean` as `@FlywayDataSource` - if you do that remember to create
+another one and mark it as `@Primary` if you want 2 data sources. 
+Or you can use Flyway's native `DataSource` by setting `flyway.[url,user,password]` 
+in external properties.
+
 There is a {github-code}/spring-boot-samples/spring-boot-sample-flyway[Flyway sample] so
 you can see how to set things up.