Cannot persist data with quarkus + hibernate reactive panache entity

I'm trying to create a Hello World application with quarkus. I have many troubles making it work.

Here are my classes :

import java.time.Duration;

import io.quarkus.hibernate.reactive.panache.Panache;
import io.quarkus.hibernate.reactive.panache.PanacheEntityBase;
import io.quarkus.hibernate.reactive.panache.common.WithSession;
import io.quarkus.hibernate.reactive.panache.common.WithSessionOnDemand;
import io.smallrye.mutiny.Uni;
import jakarta.persistence.Cacheable;
import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.Table;

@Cacheable
@Entity
@Table(name = "category", schema = "administration")
@WithSessionOnDemand
public class Category extends PanacheEntityBase {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public Long id;
    public String name;

    public static Uni<Category > add(Category cat) {
        return Panache
                .withTransaction(cat::persist)
                .replaceWith(cat)
                .ifNoItem()
                .after(Duration.ofMillis(10000))
                .fail()
                .onFailure()
                .transform(t -> new IllegalStateException(t));
    }

}

   @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Uni<List<Category>> list2() {


        // Create and persist a new category
        Category category = new Category();
        category.name = "test quarkus 3";
        Category.add(category)
                .onItem().transform(id -> id.id)
                .subscribe().with(e -> System.out.println(e));


        // Return the list of categories
        return Category.listAll();
    }

When I hit the GET endpoint, the category is created. But If I hit it 3 times in a row, I get the following error : ERROR [io.qua.mut.run.MutinyInfrastructure] (vert.x-eventloop-thread-1) Mutiny had to drop the following exception: java.lang.IllegalStateException: java.lang.IllegalStateException: No current Mutiny.Session found - no reactive session was found in the context and the context was not marked to open a new session lazily - you might need to annotate the business method with @WithSession at org.test.category.Category.lambda$1(Category.java:39)

So I tried to annotate my Category class with @WithSession and then with @WithSessionOnDemand but nothing worked. What am I doing wrong ?

you need to chain your create and query operations in a stream style thus they can access the session from thin air.

Entity class:

import jakarta.persistence.Cacheable;
import jakarta.persistence.Column;
import jakarta.persistence.Entity;

import io.quarkus.hibernate.reactive.panache.PanacheEntity;

@Entity
@Cacheable
public class Fruit extends PanacheEntity {

  @Column(length = 40, unique = false)
  public String name;

}

Service Class:

import io.quarkus.hibernate.reactive.panache.Panache;
import io.quarkus.panache.common.Sort;
import io.smallrye.mutiny.Uni;
import jakarta.enterprise.context.ApplicationScoped;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import java.time.Duration;
import java.util.List;

// first method
@Path("/fruits")
@ApplicationScoped
public class FruitResource {

  @GET
  public Uni<List<Fruit>> get() {
    return Fruit.listAll(Sort.by("name"));
  }

  @POST
  public Uni<List<Fruit>> create(Fruit fruit) {

    Uni<Long> createStage = Panache
        .withTransaction(fruit::persist)
        .replaceWith(fruit)
        .ifNoItem()
        .after(Duration.ofMillis(10000))
        .fail()
        .onFailure()
        .transform(t -> {
          System.out.println("exception happen lalal");
          t.printStackTrace();
          return new IllegalStateException(t);
        })
        .onItem().transform(item -> {
          System.out.println("fruit is created: " + item.id);
          return item.id;
        });
    Uni<List<Fruit>> queryAllFruitsStage = Fruit.listAll();

    return createStage.chain(() -> queryAllFruitsStage);

  }
}

// second method
@Path("/fruits")
@ApplicationScoped
public class FruitResource {

  @GET
  public Uni<List<Fruit>> get() {
    return Fruit.listAll(Sort.by("name"));
  }

  @POST
  public Uni<List<Fruit>> create(Fruit fruit) {

    return Panache
        .withTransaction(fruit::persist)
        .replaceWith(fruit)
        .ifNoItem()
        .after(Duration.ofMillis(10000))
        .fail()
        .onFailure()
        .transform(t -> {
          System.out.println("exception happen lalal");
          t.printStackTrace();
          return new IllegalStateException(t);
        })
        .onItem()
        .transformToUni(item -> Fruit.listAll());
  }
}

The curl test:

curl --location 'localhost:8080/fruits' \
--header 'Accept: application/json' \
--header 'Content-Type: application/json' \
--data '{
    "name": "fruit1"
}'

you may have a look at the Mutiny Patterns part at the docs Quarkus - Mutiny Primer and have a better understanding of reactive programming.