Spring Books Cloud Spanner R2DBC Sample

A derivative work based upon the cloud-spanner-spring-data-r2dbc-sample.

Prerequisites

• A valid GCP account and project id
• gcloud SDK
• JDK/JRE 11

If you want to run this sample on a Cloud Foundry foundation or Kubernetes cluster with cf-for-k8s installed, then you’ll need the

• cf CLI

and valid account credentials

In addition your platform operator must have installed and configured the gcp-service-broker.

Clone

git clone https://github.com/pacphi/spring-books.git

Build

cd spring-books
./gradlew build

Run

This sample creates a table called BOOK on application startup, and deletes it prior to application shutdown.

Locally

Run the sample from the command line, providing the following properties

• spanner.instance
• spanner.database
• gcp.project
• gcp.service_account_key_json_file

./gradlew bootRun -Dspring-boot.run.jvmArguments="-Dspanner.instance={SPANNER-INSTANCE} -Dspanner.database={SPANNER-DATABASE} -Dgcp.project={GCP-PROJECT} -Dgcp.service_account_key_json_file={PATH-TO-ACCOUNT-KEY-JSON-FILE}"

Visit http://localhost:8080/index.html in your favorite browser.

on cf-for-k8s

Login to a foundation and target an organization and space

cf api {api-host}
cf auth {username} {password}
cf t -o {organization} -s {space}

Create a Google Spanner service instance

cf create-service google-spanner sandbox spanner-sandbox-instance

Fetch the instance id of the spanner-sandbox-instance

gcloud spanner instances list

Note the NAME of the instance

Create a database within the instance

gcloud spanner databases create library --instance={name}

Replace the occurrence of {name} above with instance name of your spanner-sandbox-instance.

A single service instance may support multiple databases. In this case we’re creating a database named library.

Push the app (but don’t start it up)

cf push --no-start

The supplied manifest.yml sets the required environment variables.

Java Config via java-cfenv will take care to auto-fetch Google Spanner instance credentials at startup which are used to setup a connection and support on-demand database transactions.

Bind the Google Spanner service instance to the app

cf bind-service spring-books spanner-sandbox-instance

Set an environment variable

cf set-env spring-books GCP_SERVICE_ACCOUNT_KEY_JSON '{key-file-contents}'

We need to set an environment variable that contains the content of the service account JSON key file in order to authenticate requests from the application to the Google Spanner instance. Replace {key-file-contents} above with an actual service account key in JSON format.

Start the app

cf start spring-books

Visit the route for the app you just pushed in your favorite browser.

What does this app do?

Basically allows a librarian to maintain a simple inventory of books.

Try the different actions available:

• listing books
• adding a new book
• searching for a book by its ID

Teardown

cf unbind-service spring-books spanner-sandbox-instance
cf delete-service spanner-sandbox-instance -f
cf delete spring-books -r -f