JPrime 2024 concluded successfully!!

The organizers of JPrime 2024 have once again gone to great lengths to offer a diverse range of topics, ensuring there's something for everyone.

However, today's article isn't triggered by one of Michael Simons' lectures on "The Evolution of Integration Testing within Spring and Quarkus" although it was highly insightful. He explored integration testing strategies, focusing on the setup in Spring Boot.

The author clearly emphasized that the issues he highlighted are effectively addressed in Quarkus through the utilization of Dev Services (Figure 1). This highlights another reason why I view Spring Boot with skepticism for certain applications- its complexities are starkly contrasted by the streamlined solutions in Quarkus, particularly with the use of Dev Services.

Figure 1 – JPrime 2024

It was remarkable to witness the astonishment Dev Services sparked among the new attendees. However, it's important to note that Dev Services is not a recent feature in Quarkus; it has been an integral part of the framework for quite some time. Let’s delve deeper into Quarkus Dev Services and explore its enduring benefits.

Quarkus Dev Services

In Quarkus, Dev Services facilitate the automatic provisioning of unconfigured services in both development and testing modes. Essentially, if you include an extension without configuring it, Quarkus will automatically initiate the relevant service—often utilizing Testcontainers in the background—and configure your application to use this service efficiently.

1. Automatic Service Detection and Launch
   
   Quarkus Dev Services automates the detection and launching of necessary services like databases, message brokers, and other backend services. This function taps into the application’s dependencies specified in pom.xml or build.gradle. For instance, adding a database driver automatically triggers Dev Services to spin up a corresponding containerized instance of that database if it's not already running. The technology used here primarily involves Testcontainers, which allows for the creation of lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.

2. Dynamic Configuration Injection
   
   Once the required services are instantiated, Quarkus Dev Services dynamically injects the relevant service connection details into the application's configuration at runtime. This is done without any manual intervention, using a feature known as Continuous Testing that reroutes the standard database, or other service URLs, to the auto-provisioned Testcontainers. Configuration properties such as URLs, user credentials, and other operational parameters are seamlessly set, allowing the application to interact with these services as though they were manually configured.

3. Service-Specific Behaviors
   
   Dev Services is tailored for various types of services:

   • Databases: Automatically provides a running database tailored to your application's needs, whether it's PostgreSQL, MySQL, MongoDB, or any other supported database. Dev Services ensures that a corresponding Testcontainer is available during development.
   • Messaging Systems: For applications that use messaging systems like Kafka or AMQP, Quarkus Dev Services starts the necessary brokers using Docker and connects them with the application.
   • Custom Dev Services: Developers can extend the functionality by creating custom Quarkus extensions that leverage the Dev Services framework. This allows for tailored setups that are project-specific, offering even greater flexibility and control.

4. Network Handling and Service Isolation
   
   Each service spun up by Quarkus Dev Services runs in its isolated environment. This is crucial for ensuring that there are no port conflicts, data residue, or security issues between different development tests. Despite this isolation, services are networked appropriately using Docker, ensuring that they can communicate with each other as needed, imitating a real-world deployment atmosphere.

5. Lifecycle Management
   
   Quarkus manages the complete lifecycle of these dynamically provisioned services. When you start your application in development mode, the necessary services are started up automatically. When you stop the Quarkus application, these services are also terminated. This management includes handling data persistency as required, allowing developers to pick up right where they left off without any setup delays.

Example Usage

Consider you’re using a PostgreSQL database with Quarkus. If no existing PostgreSQL configuration is detected, Quarkus will kickstart a PostgreSQL Docker container and connect your application automatically.

These services are enabled by default in development and test modes but can be disabled if necessary via the application.properties:

quarkus.datasource.devservices.enabled=false

Let's expand on the scenario where Quarkus is using a PostgreSQL database and how the Dev Services facilitate this with minimum fuss.

If Quarkus detects that no PostgreSQL configuration is active (not running or not configured explicitly), it will automatically start up a PostgreSQL container using Docker. This is set up behind the scenes through Dev Services.

To interact with the database through an ORM layer, consider using Quarkus Panache, which simplifies Hibernate ORM operations. Here’s how to set up your environment:

1. Add Dependencies

   Firstly, include the necessary dependencies in your pom.xml:
   

   <dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-hibernate-orm-panache</artifactId>
   </dependency>
   <dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-jdbc-postgresql</artifactId>
   </dependency>
   

2. Define the Entity

   Next, define your entity, such as CityEntity:
   

   @Entity
   @Table(name = "cities")
   public class CityEntity {
   
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long id;
   
   private String name;
   
   @Column(name = "public_id")
   private String publicId;
   
   @OneToOne
   private StateEntity state;
   
   @Column(nullable = false, name = "created_at")
   private Instant createdAt;
   
   @Column(nullable = false, name = "last_modified")
   private Instant lastModified;
   
   @PrePersist
   protected void onCreate() {
    createdAt = Instant.now();
    lastModified = createdAt;
   }
   
   @PreUpdate
   protected void onUpdate() {
    lastModified = Instant.now();
   }
   }
   

3. Create the Repository

   Implement the repository which will directly interact with th database:
   

   @ApplicationScoped
   public class CityRepository implements 
   PanacheRepository<CityEntity> {
   }
   

4. Service Layer

   Define the service layer that utilizes the repository:
   

   @ApplicationScoped
   public class CityServiceImpl implements CityService {
   
     @Inject
     CityRepository cityRepository;
   
     @Override
     public long countCities() {
      return cityRepository.count();
     }
   }
   
   public interface CityService {
    long countCities();
   }
   

5. Resource Endpoint
   

   @Path("/cities")
   @Tag(name = "City Resource", description = "City APIs")
   public class CityResource {
   
     @Inject
     CityService cityService;
   
     @GET
     @Path("/count")
     @Operation(summary = "Get the total number of cities", 
      description = "Returns the total count of cities in the 
      system.")
     @APIResponse(responseCode = "200", description = "Successful 
     response", content = @Content(mediaType = "application/json", 
     schema = @Schema(implementation = Long.class)))
     public long count() {
      return cityService.countCities();
     }
    }
   

When you run your Quarkus application (mvn quarkus:dev), observe the automatic startup of the PostgreSQL container (Figure 2). This seamless integration exemplifies the power of Quarkus Dev Services, making development and testing significantly simpler by automating the configuration and connection setup to external services needed for your application.

Figure 2 – Application logs

Platform Dev Services

Quarkus Dev Services streamline the development and testing phases by handling the configuration and management of various services, allowing developers to focus more on the actual application. Quarkus supports a wide range of Dev Services, including:

• AMQP
• Apicurio Registry
• Databases
• Kafka
• Keycloak
• Kubernetes
• MongoDB
• RabbitMQ
• Pulsar
• Redis
• Vault
• Infinispan
• Elasticsearch
• Observability
• Neo4j
• WireMock
• Microcks
• Keycloak
• and many more, each designed to enhance your development environment seamlessly

Conclusion

Quarkus Dev Services represents a paradigm shift in how developers approach setting up and integrating external services during the development and testing phases. The automation of environment setup not only accelerates the development process but also reduces the potential for configuration errors, making it easier for teams to focus on creating robust, feature-rich applications.

One of the standout advantages of Quarkus Dev Services is the emphasis on developer productivity. By removing the need to manually manage service dependencies, developers can immediately begin work on business logic and application features. This streamlined workflow is particularly beneficial in microservices architectures where multiple services might require simultaneous development and integration

In conclusion, embracing Quarkus Dev Services could significantly impact your development team's effectiveness and project outcomes. The simplicity and power of Quarkus encourage experimentation,
quicker iterations, and ultimately a faster development cycle. This kind of technological leverage is what modern businesses need to thrive in the digital era.