Spring Cloud Introduction (conference format)

This is the sample app used during an introduction to Spring Cloud (conference format, ~ 50min).

The purpose of this sample is to break a monolith for a Coffee app and show how Spring Cloud can help in the process. Each commit represents a step towards the end goal, that is:

• Create a Profile controller that uses both the customer-app and the store-app to provide a customer profile including their nearest stores.

• Because we can’t hard-code the url of the store-app service, we use the Spring Boot infrastructure to create a @ConfigurationProperties bean. This step also demonstrates the use of configuration meta-data to add assistance in the IDE.

• Instead of having a configuration per app, we can share the configuration of the whole infrastructure in a single place using a config server. This step uses a separate repository for the configuration (see spring-cloud-intro-conference-config).

• We can further improve the solution by adding a service registry (Eureka) so that the apps register themselves and can easily be located. This removes the use of a key for the url of the store-app service.

• What happens if the store-app is down? If we want to avoid cascading failures, we can use Hystrix and the circuit breaker.

• Finally, what does it take to deploy this infrastructure to the Cloud? Not much really: the only thing required is the location of the config server.

Running the app locally

There are many ways to start these apps locally:

• Run the main method (e.g. CustomerApplication) right from your ide

• On the command-line, execute mvn spring-boot:run

• Package the project (mvn package) and just execute the jar, e.g. java -jar target/customer-app-0.0.1-SNAPSHOT.jar

Running the app in the cloud

If you want to run that exact same app in the cloud, you need first an account with a cloud provider. At the time of writing, you can try Pivotal Web Services for free for 60 days, check https://run.pivotal.io/

The maven configuration expects to deploy the apps to PCF, check the root pom.xml for more details. You need to provide your CloudFoundry credentials to Maven. To do so, update your ~/.m2/settings.xml

<servers>
	<server>
		<id>pcf-instance</id>
		<username>your-cf-email@example.com</username>
		<password>secret</password>
	</server>
</servers>

Tip	You can avoid storing your password in plain text in your settings.xml as Maven supports encryption

In order to avoid clashes with other apps, the project defines a project-prefix (currently set to my-test- in the root pom.xml). Make sure to update that to a unique value first!

Pushing your app to the cloud should be as easy as invoking mvn cf:push on the command-line.