Morphia, Embed Mongo and Spring. Address already in use

Question

I am trying use MongoDB, Morphia and Spring and test it, so I started use Embedded Mongo.

When I had only one DAO to persist I did not had any problem with my tests, however, in some cases I needed use more than one DAO, and in that cases my injected Datasore give me an problem: addr already in use.

My Spring Test Database Configuration is this:

@Configuration
public class DatabaseMockConfig {

private static final int PORT = 12345;

private MongodConfigBuilder configBuilder;

private MongodExecutable mongodExecutable;

private MongodProcess mongodProcess;


@Bean
@Scope("prototype")
public MongodExecutable getMongodExecutable() {
    return this.mongodExecutable;
}

@Bean
@Scope("prototype")
public MongodProcess mongodProcess() {
    return this.mongodProcess;
}

@Bean
public IMongodConfig getMongodConfig() throws UnknownHostException, IOException {

    if (this.configBuilder == null) {
        configBuilder = new MongodConfigBuilder().version(Version.Main.PRODUCTION).net(new Net(PORT, Network.localhostIsIPv6()));
    }

    return this.configBuilder.build();
}

@Autowired
@Bean
@Scope("prototype")
public Datastore datastore(IMongodConfig mongodConfig) throws IOException {

    MongodStarter starter = MongodStarter.getDefaultInstance();

    this.mongodExecutable = starter.prepare(mongodConfig);

    this.mongodProcess = mongodExecutable.start();

    MongoClient mongoClient = new MongoClient("localhost", PORT);

    return new Morphia().createDatastore(mongoClient, "morphia");
}

@Autowired
@Bean
@Scope("prototype")
public EventDAO eventDAO(final Datastore datastore) {
    return new EventDAO(datastore);
}

@Autowired
@Bean
@Scope("prototype")
public EditionDAO editionDAO(final Datastore datastore) {
    return new EditionDAO(datastore);
}
}

And my DAO classes are similar to that

@Repository
public class EventDAO {

private final BasicDAO<Event, ObjectId> basicDAO;

@Autowired
public EventDAO(final Datastore datastore) {
    this.basicDAO = new BasicDAO<>(Event.class, datastore);
}
...
}

My test class is similar to that:

@ContextConfiguration(classes = AppMockConfig.class)
@RunWith(SpringJUnit4ClassRunner.class)
public class EventDAOTest {

@Autowired
private EventDAO eventDAO;

@Autowired
private MongodExecutable mongodExecutable;

@Autowired
private MongodProcess mongodProcess;

@Rule
public ExpectedException expectedEx = ExpectedException.none();

@After
public void tearDown() {

    this.mongodProcess.stop();
    this.mongodExecutable.stop();
}
...
}

I use prototype scope to solve problem with singleton and make sure that my mock database is clean when I start my test, after that I stop mongod process and mongod executable.

However since I need use more than one DAO I receive that error:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'editionDAO' defined in class br.com.mymusicapp.spring.DatabaseMockConfig: Unsatisfied dependency expressed through constructor argument with index 0 of type [org.mongodb.morphia.Datastore]: : 
Error creating bean with name 'datastore' defined in class br.com.mymusicapp.spring.DatabaseMockConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.mongodb.morphia.Datastore]: 
Factory method 'datastore' threw exception; nested exception is java.io.IOException: Could not start process: ERROR: listen(): bind() failed errno:98 Address already in use for socket: 0.0.0.0:12345
2015-01-04T01:05:04.128-0200 [initandlisten] ERROR:   addr already in use

I know what the error means, I just do not know how can I design my Configuration to solve that. As last option I am considering install a localhost MongoDB just for tests, however I think could be a better solution

Answer 1

That is based on the embedded mongod by flapdoodle, right?

If you want to run multiple tests in parallel (could be changed via JUnit annotations, but it's probably faster in parallel), you cannot use a single, hardcoded port. Instead, let the embedded process select an available port automatically.