Reactive mongoDB in Micronaut

I am using the mongoDb with Micronaut and trying to insert, get, delete and update the record. I have followed the guideline from here https://github.com/ilopmar/micronaut-mongo-reactive-sample

Since I don't have a database created in the MongoDB,

Micronaut configuration

mongodb:
  uri: "mongodb://${MONGO_HOST:localhost}:${MONGO_PORT:27017/FeteBird-Product}"

Repository

@Singleton
public class Repository<T>  implements IRepository<T>{
    private final MongoClient mongoClient;
    public Repository(MongoClient mongoClient) {
        this.mongoClient = mongoClient;
    }

    @Override
    public MongoCollection<T> getCollection(String collectionName, Class<T> typeParameterClass) {
        return mongoClient
                .getDatabase("FeteBird-Product")
                .getCollection(collectionName, typeParameterClass);
    }
}

Insert operation

public Flowable<List<Product>> findByFreeText(String text) {
        LOG.info(String.format("Listener --> Listening value = %s", text));
        try {
            Product product = new Product();
            product.setDescription("This is the test description");
            product.setName("This is the test name");
            product.setPrice(100);
            product.setId(UUID.randomUUID().toString());
            Single.fromPublisher(this.repository.getCollection("product", Product.class).insertOne(product))
                    .map(item -> product);

        } catch (Exception ex) {
            System.out.println(ex);
        }

        return Flowable.just(List.of(new Product()));
    }

There is no record inserted or created an database, What I am doing wrong ?

Yes, nothing is created, because you are using reactive Single without subscription. And then it is never executed. So, you have to call subscribe() to tell the Single that it can start working:

Single.fromPublisher(repository.getCollection("product", Product.class).insertOne(product))
    .subscribe();

Note: the mapping of item to product .map(item -> product) is unnecessary when you don't use the result of the subscription.

There is no subscription in the linked example for the first look, because the controller method returns Single<User> and then the subscriber in that case is the REST operation caller.