spring boot - managing transactions & multiple datasources
I tried to extend the Managing Transactions example in the spring boot guides to two datasources, but the @Transaction annotation seems to work for only one of the datasources.
In "Application.java" I added the beans for the two datasources and their JdbcTemplates. In "BookingService.java" I used the JdbcTemplate belonging to the second datasource.
Here is my "Application.java":
package hello;
import javax.sql.DataSource;
import org.junit.Assert;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.core.JdbcTemplate;
@SpringBootApplication
public class Application {
private static final Logger log = LoggerFactory.getLogger(Application.class);
@Bean
BookingService bookingService() {
return new BookingService();
}
@Primary
@Bean(name="datasource1")
@ConfigurationProperties(prefix="datasource1")
DataSource datasource1() {
return DataSourceBuilder.create().build();
}
@Bean(name="jdbcTemplate1")
@Autowired
JdbcTemplate jdbcTemplate1(@Qualifier ("datasource1") DataSource datasource) {
return new JdbcTemplate(datasource);
}
@Bean(name="datasource2")
@ConfigurationProperties(prefix="datasource2")
DataSource datasource2() {
return DataSourceBuilder.create().build();
}
@Bean(name="jdbcTemplate2")
@Autowired
JdbcTemplate jdbcTemplate2(@Qualifier ("datasource2") DataSource dataSource) {
JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
log.info("Creating tables");
jdbcTemplate.execute("drop table BOOKINGS if exists");
jdbcTemplate.execute("create table BOOKINGS("
+ "ID serial, FIRST_NAME varchar(5) NOT NULL)");
return jdbcTemplate;
}
public static void main(String[] args) {
ApplicationContext ctx = SpringApplication.run(Application.class, args);
BookingService bookingService = ctx.getBean(BookingService.class);
bookingService.book("Alice", "Bob", "Carol");
Assert.assertEquals("First booking should work with no problem", 3,
bookingService.findAllBookings().size());
try {
bookingService.book("Chris", "Samuel");
}
catch (RuntimeException e) {
log.info("v--- The following exception is expect because 'Samuel' is too big for the DB ---v");
log.error(e.getMessage());
}
for (String person : bookingService.findAllBookings()) {
log.info("So far, " + person + " is booked.");
}
log.info("You shouldn't see Chris or Samuel. Samuel violated DB constraints, and Chris was rolled back in the same TX");
Assert.assertEquals("'Samuel' should have triggered a rollback", 3,
bookingService.findAllBookings().size());
try {
bookingService.book("Buddy", null);
}
catch (RuntimeException e) {
log.info("v--- The following exception is expect because null is not valid for the DB ---v");
log.error(e.getMessage());
}
for (String person : bookingService.findAllBookings()) {
log.info("So far, " + person + " is booked.");
}
log.info("You shouldn't see Buddy or null. null violated DB constraints, and Buddy was rolled back in the same TX");
Assert.assertEquals("'null' should have triggered a rollback", 3, bookingService
.findAllBookings().size());
}
}
And here is "BookingService.java":
package hello;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.transaction.annotation.Transactional;
public class BookingService {
private final static Logger log = LoggerFactory.getLogger(BookingService.class);
@Autowired
@Qualifier("jdbcTemplate2")
JdbcTemplate jdbcTemplate;
@Transactional
public void book(String... persons) {
for (String person : persons) {
log.info("Booking " + person + " in a seat...");
jdbcTemplate.update("insert into BOOKINGS(FIRST_NAME) values (?)", person);
}
};
public List<String> findAllBookings() {
return jdbcTemplate.query("select FIRST_NAME from BOOKINGS", new RowMapper<String>() {
@Override
public String mapRow(ResultSet rs, int rowNum) throws SQLException {
return rs.getString("FIRST_NAME");
}
});
}
}
These are the apllication properties in "application.yml":
datasource1:
url: "jdbc:h2:~/h2/ds1;DB_CLOSE_ON_EXIT=FALSE"
username: "sa"
datasource2:
url: "jdbc:h2:~/h2/ds2;DB_CLOSE_ON_EXIT=FALSE"
username: "sa"
The "pom.xml" here is the same as in Managing Transactions.
When the @Primary annotation is on the datasource2 bean, everything works as expected. When the @Primary annotation is on the datasource1 bean, the write in datasource2 is not transactional and one gets the following output:
...
2016-05-27 16:01:23.775 INFO 884 --- [ main] hello.Application : So far, Alice is booked.
2016-05-27 16:01:23.775 INFO 884 --- [ main] hello.Application : So far, Bob is booked.
2016-05-27 16:01:23.775 INFO 884 --- [ main] hello.Application : So far, Carol is booked.
2016-05-27 16:01:23.775 INFO 884 --- [ main] hello.Application : So far, Chris is booked.
2016-05-27 16:01:23.775 INFO 884 --- [ main] hello.Application : You shouldn't see Chris or Samuel. Samuel violated DB constraints, and Chris was rolled back in the same TX
Exception in thread "main" 2016-05-27 16:01:23.776 INFO 884 --- [ Thread-2] s.c.a.AnnotationConfigApplicationContext : Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@3901d134: startup date [Fri May 27 16:01:22 CEST 2016]; root of context hierarchy
java.lang.AssertionError: 'Samuel' should have triggered a rollback expected:<3> but was:<4>
at org.junit.Assert.fail(Assert.java:88)
at org.junit.Assert.failNotEquals(Assert.java:834)
at org.junit.Assert.assertEquals(Assert.java:645)
at hello.Application.main(Application.java:84)
2016-05-27 16:01:23.778 INFO 884 --- [ Thread-2] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
So "Chris" wasn't rolled back.
I guess it has something to do with properly initializing both databases. Is this a bug, or am I missing something here?
Thanks!
Answer
I added two beans in "Application.java":
@Bean(name="tm1")
@Autowired
DataSourceTransactionManager tm1(@Qualifier ("datasource1") DataSource datasource) {
DataSourceTransactionManager txm = new DataSourceTransactionManager(datasource);
return txm;
}
@Bean(name="tm2")
@Autowired
DataSourceTransactionManager tm2(@Qualifier ("datasource2") DataSource datasource) {
DataSourceTransactionManager txm = new DataSourceTransactionManager(datasource);
return txm;
}
and changed the @Transactional in "BookingService.java" to:
@Transactional("tm2")
So now we have two resource-local transaction managers, one for each datasource, and it works as expected.
Many thanks to M.Deinum!