Spring does not see repository during scan on app start

Question

Have sandbox springboot app. Decided to try reactive approach, postgres is used as database, I added r2dbc to the project to make my repository reactive. Here is my code:

@SpringBootApplication
public class Springboot2Application {
public static void main(String[] args) {
    SpringApplication.run(Springboot2Application.class, args);
   }
}

@Repository
public interface ToDoRepository extends 
            ReactiveCrudRepository<ToDo,String> {
}

@RestController
@RequestMapping("/api/v1")
public class ToDoController {
    private final ToDoRepository repository;
    public ToDoController(ToDoRepository repository) {
        this.repository = repository;
    }

    @GetMapping(value = "/to-do", produces = {
            MediaType.APPLICATION_JSON_VALUE, 
            MediaType.APPLICATION_XML_VALUE, 
            MediaType.TEXT_XML_VALUE})
    public ResponseEntity<Flux<ToDo>> getToDos(@RequestHeader 
                                          HttpHeaders headers){
        return ResponseEntity.ok().body(repository.findAll());
    }
}

@Data
@RequiredArgsConstructor
@Entity
@Table(name = "todo")
public class ToDo {
    @Id
    @NotNull
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    private String id;
    @NotNull
    @NotBlank
    private String description;
    @CreationTimestamp
    private Timestamp created;
    @UpdateTimestamp
    private Timestamp modified;
    private boolean completed;
}

r2dbc config:

@Configuration
@EnableR2dbcRepositories(basePackages = 
   "com.springboot2.repository")
public class R2DBCConfig extends AbstractR2dbcConfiguration {
@Bean
public ConnectionFactory connectionFactory() {
    return ConnectionFactories.get(
            ConnectionFactoryOptions.builder()
                    .option(DRIVER, "postgresql")
                    .option(HOST, "localhost")
                    .option(PORT, 5432)
                    .option(USER, "admin")
                    .option(PASSWORD, "admin")
                    .option(DATABASE, "springdb")
                    .build());
   }
 }

On application start I'm getting:

Description:

Parameter 0 of constructor in com.springboot2.controller.ToDoController required a bean of type 'com.springboot2.repository.ToDoRepository' that could not be found.

Action:

Consider defining a bean of type 'com.springboot2.repository.ToDoRepository' in your configuration.

I tried to add @ComponentsScan, tried to move ToDoRepository to the root near Springboot2Application, I dont understand why Spring doesn't see repository interface

pom.file:

    <?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.springboot</groupId>
    <artifactId>springboot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot2</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>8</java.version>
        <spring-cloud.version>2021.0.3</spring-cloud.version>
<!--        <spring-shell.version>2.1.0</spring-shell.version>-->
    </properties>
    <dependencies>
        <!--        DB,ORM, and plugins-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-r2dbc</artifactId>
        </dependency>
        <dependency>
            <groupId>io.r2dbc</groupId>
            <artifactId>r2dbc-postgresql</artifactId>
            <version>0.8.1.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <!--        Reactive libs-->
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Answer 1

I've changed from ReactiveCrudRepository to R2dbcRepository and it worked for me

Answer 2

In addition to @kerbermeister's answer below my findings regarding the mentioned issue: Adding the dependency

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-r2dbc</artifactId>
</dependency>

And of course a dependency to a RDBMS driver, e.g.:

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>r2dbc-postgresql</artifactId>
</dependency>

is not sufficient. In my case I had to change the Repositories from extending ReactiveCrudRepository to R2dbcRepository. Furthermore it's important to configure a datasource which points to a url starting with r2dbc:. If done via application.properties|yaml the path for the url must be changed from spring.datasource.url to spring.r2dbc.url.

Answer 3

My guess the reason is that you have added r2dbc driver to your project, but haven't added spring-boot-starter-data-r2dbc

So, consider this dependency in your pom.xml file (this is the latest version at the time of writing this answer) :

<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-r2dbc -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-r2dbc</artifactId>
    <version>3.0.2</version>
</dependency>

EDIT:

1. Also you can try to use @EnableR2dbcRepositories and specify the package with your repository.

2. One more possible way to solve this is to extend your repository from R2dbcRepository, instead of ReactiveCrudRepository This may help when you have multiple spring data reactive modules (r2dbc and something else) being used in the same project. Since ReactiveCrudRepository is a generic interface Spring does not know how to properly configure these beans.