Using the open-source R2DBC driver

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R2DBC is a specification for non-blocking access to relational databases, based on Reactive Streams. Your application can make use of the reactive database connectivity with Spanner by using the Spanner R2DBC driver.

Adding Dependencies

Spring Data users should use the Spring Data R2DBC dialect for Spanner; all other users should bring in the Spanner R2DBC driver only.

Using the Spanner R2DBC driver

To add only the Spanner R2DBC driver to your application, add the following dependency:

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>cloud-spanner-r2dbc</artifactId>
  <version>1.2.0</version>
</dependency>

See the Spanner R2DBC driver GitHub repo for full documentation and sample code.

Using the Spring Data R2DBC dialect for Spanner

For users of the Spring Framework, Spring Data provides familiar abstractions to simplify interaction with common database operations.

To use Spring Data R2DBC features with Spanner, add the following dependency to your project. The driver is a transitive dependency of the dialect.

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>cloud-spanner-spring-data-r2dbc</artifactId>
  <version>1.2.0</version>
</dependency>

See the Spring Data R2DBC reference to learn how to use its template and repositories. See the Spring Boot reference to see which objects are automatically configured for you.

A sample application is also available.

Spring Boot configuration

Regardless of which R2DBC dependency you use, if your application is based on Spring Boot, the framework will attempt to automatically configure and provide a connection factory for you.

Provide a spring.r2dbc.url property to let autoconfiguration take care of R2DBC connection factory configuration. The format is shown in the following sample application.properties entry:

spring.r2dbc.url=\
r2dbc:cloudspanner://spanner.googleapis.com:443/projects/${project}/instances/${instance}/databases/${database}

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