server-spring-data-mongo.md

SDA Commons Server Spring Data Mongo

The module sda-commons-server-spring-data-mongo is used to work with MongoDB using Spring Data Mongo.

Initialization

The SpringDataMongoBundle should be added as a field in the application class instead of being anonymously added in the initialize method like other bundles of this library.

The Dropwizard application's config class needs to provide a MongoConfiguration.

Please refer to the official documentation how to annotate your entity classes correctly, e.g. by adding @Document, @MongoId or @Indexed.

public class MyApp extends Application<MyConfiguration> {

  private final SpringDataMongoBundle<MyConfiguration> springDataMongoBundle =
      SpringDataMongoBundle.builder()
          .withConfigurationProvider(MyConfiguration::getSpringDataMongo)
          .withEntites(MyEntity.class)
          .build();

  private PersonRepository personRepository;

  @Override
  public void initialize(Bootstrap<MyConfiguration> bootstrap) {
    bootstrap.addBundle(springDataMongoBundle);
  }

  @Override
  public void run(MyConfiguration configuration, Environment environment) {
    personRepository = springDataMongoBundle.createRepository(PersonRepository.class);
  }

  public MongoOperations getMongoOperations() {
    return springDataMongoBundle.getMongoOperations();
  }

  public GridFsOperations getGridFsOperations() {
    return springDataMongoBundle.getGridFsOperations();
  }

  public PersonRepository getPersonRepository() {
    return personRepository;
  }
}

Configuration

The database connection is configured in the config.yaml of the application, specifically the connectionString.

mongo:
  connectionString: "${MONGODB_CONNECTION_STRING:-}"

Example config for developer machines using local-infra:

mongo:
  connectionString: "mongodb://mongo-1:27118,mongo-2:27119,mongo-3:27120/myAppName?replicaSet=sda-replica-set-1"

In tests the config is derived from the MongoDbClassExtension. See sda-commons-server-mongo-testing for details.

Inheritance in Entities

It is strongly recommended to annotate all types that are used in a field that does not exactly match the type with @TypeAlias. Using @TypeAlias will replace the default class name as discriminator with the given value in the annotation and gives you the ability for refactoring of the model classes. This rule applies for all types that are a subclass of an (abstract) super class, types that are stored in a field defined as Object and all types that are stored in a shared collection. The latter are usually a subtype of an abstract class to support a common repository.

It is important to register each class that is annotated with @TypeAlias by using withEntities in the builder of the bundle. If not registered there, the mapping is unknown when reading entities.

Health check

A health check with the name mongo is automatically registered to test the mongo connection. A simple ping command to the database is used.

Index creation

The bundle will create indexes automatically by default. You can change the configuration using the builder:

private final SpringDataMongoBundle<MyConfiguration> springDataMongoBundle =
  SpringDataMongoBundle.builder()
      .withConfigurationProvider(MyConfiguration::getSpringDataMongo)
      .withEntites(MyEntity.class)
      .disableAutoIndexCreation()
      .build();

Spring Data Mongo Repositories

The bundle support creating Spring Data Mongo repositories that are defined by an interface. You can create an instance of your repository using the bundle's createRepository method that accepts the interface.

public interface PersonRepository extends PagingAndSortingRepository<Person, ObjectId> {

  // additional custom finder methods go here
}

var personRepository = springDataMongoBundle.createRepository(PersonRepository.class);

CA Certificates support

Instead of providing caCertificate as an environment variable, mount the CA certificates in PEM format in the directory /var/trust/certificates. Certificates available in subdirectories will also be loaded.

Note that this directory is also configurable through the Dropwizard config class. The config class should then provide a CaCertificateConfiguration to the bundle builder. See sda-commons-shared-certificates for details.