Springboot Mongo db methods doesnt rollback transactions

Question

Hi i am using 2 mongo template in my codebase and my code saves data in mongo db using both mongo template and Spring repository class.save() .In methods which has @Transactional doesnt rollback DB changes even if some error occurs in code execution. Below is the snippet of my mongoconfig configurations

@Configuration
@EnableMongoAuditing
@EnableMongoRepositories
public class MongoConfig extends AbstractMongoClientConfiguration {

    @Value("${common.db.name}")
    private String dbName;

    @Value("${SPRING_DATA_MONGODB_URI}")
    private String dbUrl;

    public String getDbName() {
        return dbName;
    }

    public void setDbName(String dbName) {
        this.dbName = dbName;
    }
    @Override
    protected String getDatabaseName() {
        return dbName;
    }

    /**
     *  Below bean is created as we want to make our code transactional.
     * @param dbFactory
     * @return
     */
    @Bean(name="primaryTransactionManager")
    MongoTransactionManager transactionManager(MongoDatabaseFactory dbFactory) {
        MongoTransactionManager transactionManager = new MongoTransactionManager(dbFactory);
        transactionManager.setRollbackOnCommitFailure(true);
        return transactionManager;
    }

    @Override
    public MongoClient mongoClient() {
        ConnectionString connectionString = new ConnectionString(dbUrl);
        MongoClientSettings mongoClientSettings = MongoClientSettings.builder().applyConnectionString(connectionString).build();
        return MongoClients.create(mongoClientSettings);
    }

    @Bean(name="primaryMongoTemplate")
    public MongoTemplate mongoTemplate() {
        return new MongoTemplate(mongoClient(), getDbName());
    }
}

@Configuration
@EnableMongoRepositories
public class SecondaryMongoConfig {

    @Value("${common.secondary.db.name}")
    private String dbName;

    @Value("${COMMON_SECONDARY_SPRING_DATA_MONGODB_URI}")
    private String mongoDBURI;

    public String getMongoDBURI() {
        return mongoDBURI;
    }

    public void setMongoDBURI(String mongoDBURI) {
        this.mongoDBURI = mongoDBURI;
    }

    public String getDbName() {
        return dbName;
    }

    public void setDbName(String dbName) {
        this.dbName = dbName;
    }

    /**
     * Below bean is created as we want to make our code transactional.
     * @param dbFactory
     * @return
     */
    @Bean(name="secondaryTransactionManager")
    MongoTransactionManager transactionManager(MongoDatabaseFactory dbFactory) {
        MongoTransactionManager transactionManager = new MongoTransactionManager(dbFactory);
        transactionManager.setRollbackOnCommitFailure(true);
        return new MongoTransactionManager(dbFactory);
    }
    
    @Bean(name="secondaryMongoClient")
    public MongoClient secondaryMongoClient() {
        ConnectionString connectionString = new ConnectionString(getMongoDBURI());
        MongoClientSettings mongoClientSettings = MongoClientSettings.builder()
                .applyConnectionString(connectionString)
                .build();

        return MongoClients.create(mongoClientSettings);
    }

    @Bean(name="secondaryMongoTemplate")
    public MongoTemplate secondaryMongoTemplate() {
        return new MongoTemplate(secondaryMongoClient(), getDbName());
    }
}

Below is my sample code snippet of method annoted with @Transactional

    @Override
    @Transactional(transactionManager = "primaryTransactionManager",rollbackFor = {Exception.class})
    public String addNewRecipe() throws Exception{
        RecipesDAO recipesDao = new RecipesDAO();
        recipesDao.setResourceId(UUID.randomUUID().toString());
        recipeRepository.save(recipesDao);
        throw new Exception();
    //  return "dummy";
    }

Answer 1

I got solution after checking each and every method of classes used in my class MongoConfig.java.Below is the snippet of code which i had to use in order to rollback transactions when exceptions occured in code execution flow

@Bean(name="primaryMongoTemplate")
    public MongoTemplate mongoTemplate() {
        MongoTemplate primaryMongoTemplate = new MongoTemplate(mongoClient(), getDbName());
        primaryMongoTemplate.setSessionSynchronization(SessionSynchronization.ALWAYS);
        return primaryMongoTemplate;
    }

    @Bean(name="secondaryMongoTemplate")
    public MongoTemplate secondaryMongoTemplate() {
        MongoTemplate secondaryMongoTemplate = new MongoTemplate(secondaryMongoClient(), getDbName());
        secondaryMongoTemplate.setSessionSynchronization(SessionSynchronization.ALWAYS);
        return secondaryMongoTemplate;
    }

Earlier wherever code of creating new or modifying mongodb docs was there like say somerepository.save(s) code used to create or modify documents immedialtely but by adding primaryMongoTemplate.setSessionSynchronization(SessionSynchronization.ALWAYS); and secondaryMongoTemplate.setSessionSynchronization(SessionSynchronization.ALWAYS); code waits for complete execution flow and checks if any exception occured in this execution flow.It creates or modifies documents only after checking no exception occured in execution flow.