Spring boot data R2DBC requires transaction for read operations - postgresql

Question

Im trying to fetch a list of objects from the database using Spring boot Webflux with the postgres R2DBC driver, but I get an error saying:
value ignored org.springframework.transaction.reactive.TransactionContextManager$NoTransactionInContextException: No transaction in context Context1{reactor.onNextError.localStrategy=reactor.core.publisher.OnNextFailureStrategy$ResumeStrategy#7c18c255}
it seems all DatabaseClient operations requires to be wrap into a transaction.
I tried different combinations of the dependencies between spring-boot-data and r2db but didn't really work.
Version:
<spring-boot.version>2.2.0.RC1</spring-boot.version>
<spring-data-r2dbc.version>1.0.0.BUILD-SNAPSHOT</spring-data-r2dbc.version>
<r2dbc-releasetrain.version>Arabba-M8</r2dbc-releasetrain.version>
Dependencies:
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-r2dbc</artifactId>
<version>${spring-data-r2dbc.version}</version>
</dependency>
<dependency>
<groupId>io.r2dbc</groupId>
<artifactId>r2dbc-postgresql</artifactId>
</dependency>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
</dependency>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>io.r2dbc</groupId>
<artifactId>r2dbc-bom</artifactId>
<version>${r2dbc-releasetrain.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
fun findAll(): Flux<Game> {
val games = client
.select()
.from(Game::class.java)
.fetch()
.all()
.onErrorContinue{ throwable, o -> System.out.println("value ignored $throwable $o") }
games.subscribe()
return Flux.empty()
}
#Table("game")
data class Game(#Id val id: UUID = UUID.randomUUID(),
#Column("guess") val guess: Int = Random.nextInt(500))
Github repo: https://github.com/odfsoft/spring-boot-guess-game/tree/r2dbc-issue
I expect read operations to not require #Transactional or to run the query without wrapping into the transactional context manually.
UPDATE:
After a few tries with multiple version I manage to find a combination that works:
<spring-data-r2dbc.version>1.0.0.BUILD-SNAPSHOT</spring-data-r2dbc.version>
<r2dbc-postgres.version>0.8.0.RC2</r2dbc-postgres.version>
Dependencies:
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-r2dbc</artifactId>
<version>${spring-data-r2dbc.version}</version>
</dependency>
<dependency>
<groupId>io.r2dbc</groupId>
<artifactId>r2dbc-postgresql</artifactId>
<version>${r2dbc-postgres.version}</version>
</dependency>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>io.r2dbc</groupId>
<artifactId>r2dbc-bom</artifactId>
<version>Arabba-RC2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
it seems the versions notation went from 1.0.0.M7 to 0.8.x for r2dbc due to the following:
https://r2dbc.io/2019/05/13/r2dbc-0-8-milestone-8-released
https://r2dbc.io/2019/10/07/r2dbc-0-8-rc2-released
but after updating to the latest version a new problem appear which is that a transaction is required to run queries as follow:
Update configuration:
#Configuration
class PostgresConfig : AbstractR2dbcConfiguration() {
#Bean
override fun connectionFactory(): ConnectionFactory {
return PostgresqlConnectionFactory(
PostgresqlConnectionConfiguration.builder()
.host("localhost")
.port(5432)
.username("root")
.password("secret")
.database("game")
.build())
}
#Bean
fun reactiveTransactionManager(connectionFactory: ConnectionFactory): ReactiveTransactionManager {
return R2dbcTransactionManager(connectionFactory)
}
#Bean
fun transactionalOperator(reactiveTransactionManager: ReactiveTransactionManager) =
TransactionalOperator.create(reactiveTransactionManager)
}
Query:
fun findAll(): Flux<Game> {
return client
.execute("select id, guess from game")
.`as`(Game::class.java)
.fetch()
.all()
.`as`(to::transactional)
.onErrorContinue{ throwable, o -> System.out.println("value ignored $throwable $o") }
.log()
}
Disclaimer this is not mean to be used in production!! still before GA.