Cats and Dogs

Backend and Frontend are sample applications demonstrating the use of Service Registry and Circuit Breaker from Spring Cloud Services with Container-to-Container (C2C) Networking from Cloud Foundry.

This app is a "blend" of the CF Netowrking Release cats-and-dogs example app, and the Spring Cloud Services who is home? example app.

Building and Deploying

Using Gradle, run ./gradlew build (OS X, Linux) or gradlew.bat build (Windows).

$ ./gradlew build

Create the service registry and circuit dashboard

$ ./scripts/create_services.sh

Deploy the frontend and backend apps

$ ./scripts/deploy_apps.sh

You may also need to set the TRUST_CERTS environment variable to the API endpoint of your Elastic Runtime instance (as in api.example.com), then restage the applications so that the changes will take effect. Setting TRUST_CERTS causes Spring Cloud Services to add the the SSL certificate at the specfied API endpoint to the JVM's truststore, so that the client application can communicate with a Service Registry service instance (see the Service Registry Documentation.

$ cf set-env backend TRUST_CERTS api.wise.com
Setting env variable 'TRUST_CERTS' to 'api.wise.com' for app backend in org myorg / space development as user...
OK
TIP: Use 'cf restage' to ensure your env variable changes take effect
$ cf restage backend

$ cf set-env frontend TRUST_CERTS api.wise.com
Setting env variable 'TRUST_CERTS' to 'api.wise.com' for app frontend in org myorg / space development as user...
OK
TIP: Use 'cf restage' to ensure your env variable changes take effect
$ cf restage frontend

NOTE

By default, the Spring Cloud Services Starters for Service Registry causes all application endpoints to be secured by HTTP Basic authentication. For more information or if you wish to disable this, see the documentation. HTTP Basic authentication is disabled in these sample applications.

Trying It Out

Visit [ROUTE]/, where [ROUTE] is the route bound to the Frontend application. The Frontend application will use the Service Registry to look up the Backend application and get a message back, which contains a URL to a cat picture.

When the Frontend and Backend applications are initially deployed, the Frontend application will not be able to contact the Backend application. This is because a policy has not been created between the applications using the CF CLI network policy commands.

To create a policy, you can run the following command to allow communication between Frontend and Backend applications:

cf add-network-policy frontend --destination-app backend --protocol tcp --port 8080

To remove the network policy, you can run this command:

cf remove-network-policy frontend --destination-app backend --protocol tcp --port 8080

And to see existing policies:

cf network-policies

For more information about the Service Registry and its use in a client application, see the Service Registry documentation.