Example Cassandra Application

This simple application illustrates the use of the Cassandra data service in a Ruby application running on Cloud Foundry.

Installation

Create a Cassandra service instance

Find your Cassandra service via cf marketplace.

$ cf marketplace
Getting services from marketplace in org testing / space testing as me...
OK

service       plans     description
cassandra   default   A simple cassandra service broker implementation

Our service is called cassandra. To create an instance of this service, use:

$ cf create-service cassandra default cassandra-instance

Push the Example Application

The example application comes with a Cloud Foundry manifest.yml file, which provides all of the defaults necessary for an easy cf push.

$ cf push
Using manifest file cf-cassandra-example-app/manifest.yml

Creating app cassandra-example-app in org testing / space testing as me...
OK

Using route cassandra-example-app.example.com
Binding cassandra-example-app.example.com to cassandra-example-app...
OK

Uploading cassandra-example-app...
Uploading from: cf-cassandra-example-app
...
Showing health and status for app cassandra-example-app in org testing / space testing as me...
OK

requested state: started
instances: 0/1
usage: 256M x 1 instances
urls: cassandra-example-app.10.244.0.34.xip.io

     state     since                    cpu    memory          disk
#0   running   2017-10-31 01:42:43 PM   0.0%   75.5M of 256M   0 of 1G

If you now curl the application, you'll see that the application has detected that it's not bound to a cassandra instance.

$ curl http://cassandra-example-app.example.com/

      You must bind a Cassandra service instance to this application.

      You can run the following commands to create an instance and bind to it:

        $ cf create-service cassandra default cassandra-instance
        $ cf bind-service cassandra-example-app cassandra-instance

Bind the Instance

Now, simply bind the cassandra instance to our application.

$ cf bind-service cassandra-example-app cassandra-instance
Binding service cassandra-instance to app cassandra-example-app in org testing / space testing as me...
OK
TIP: Use 'cf push' to ensure your env variable changes take effect
$ cf push

Usage

You can now create and drop tables by POSTing and DELETEing to myTable.

$ export APP=http://cassandra-example-app.example.com
$ curl -X POST $APP/myTable
$ curl -X DELETE $APP/myTable
bar

Of course, be sure to replace example.com with the actual domain of your Cloud Foundry installation.