Spring Boot

A Spring Boot-based simple web application

Before you begin

Install Verrazzano by following the installation instructions.

NOTE: The Spring Boot example application deployment files are contained in the Verrazzano project located at <VERRAZZANO_HOME>/examples/springboot-app, where VERRAZZANO_HOME is the root of the Verrazzano project.

Deploy the application

This example provides a simple web application developed using Spring Boot. For more information and the source code of this application, see the Verrazzano Examples.

NOTE

To run this application in the default namespace:

$ kubectl label namespace default verrazzano-managed=true istio-injection=enabled

If you chose the default namespace, you can skip Step 1 and ignore the -n option in the rest of the commands.

Create a namespace for the Spring Boot application and add a label identifying the namespace as managed by Verrazzano.
```
$ kubectl create namespace springboot
$ kubectl label namespace springboot verrazzano-managed=true istio-injection=enabled
```
To deploy the application, apply the Spring Boot OAM resources.
```
$ kubectl apply -f https://raw.githubusercontent.com/verrazzano/verrazzano/master/examples/springboot-app/springboot-comp.yaml -n springboot
$ kubectl apply -f https://raw.githubusercontent.com/verrazzano/verrazzano/master/examples/springboot-app/springboot-app.yaml -n springboot
```
Wait for the Spring Boot application to be ready.
```
$ kubectl wait \
   --for=condition=Ready pods \
   --all \
   -n springboot \
   --timeout=300s
```

Explore the application

Get the generated host name for the application.
```
$ HOST=$(kubectl get gateways.networking.istio.io \
     -n springboot \
     -o jsonpath={.items[0].spec.servers[0].hosts[0]})
$ echo $HOST

# Sample output
springboot-appconf.springboot.11.22.33.44.nip.io
```
Get the EXTERNAL_IP address of the istio-ingressgateway service.
```
$ ADDRESS=$(kubectl get service \
     -n istio-system istio-ingressgateway \
     -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
$ echo $ADDRESS

# Sample output
11.22.33.44
```
Access the application.
- Using the command line
```
# The expected response of this query is the HTML of a web page
$ curl -sk \
   https://${HOST} \
   --resolve ${HOST}:443:${ADDRESS}

$ curl -sk \
   https://${HOST}/facts \
   --resolve ${HOST}:443:${ADDRESS}

# Sample output
In 1524, Verrazzano became the first European to enter the New York Harbor and the Hudson River.
```
  If you are using nip.io, then you do not need to include --resolve.
- Local testing with a browser
  
  Temporarily, modify the /etc/hosts file (on Mac or Linux) or c:\Windows\System32\Drivers\etc\hosts file (on Windows 10), to add an entry mapping the host name to the ingress gateway’s EXTERNAL-IP address. For example:
```
11.22.33.44 springboot.example.com
```
  Then, you can access the application in a browser at https://springboot.example.com/ and https://springboot.example.com/facts.
  - If you are using nip.io, then you can access the application in a browser using the HOST variable (for example, https://${HOST}/facts).
  - If you are going through a proxy, you may need to add *.nip.io to the NO_PROXY list.
- Using your own DNS name
  
  Point your own DNS name to the ingress gateway’s EXTERNAL-IP address.
  - In this case, you would need to have edited the springboot-app.yaml file to use the appropriate value under the hosts section (such as yourhost.your.domain), before deploying the Spring Boot application.
  - Then, you can use a browser to access the application at https://<yourhost.your.domain>/ and https://<yourhost.your.domain>/facts.
    
    The actuator endpoint is accessible under the path /actuator and the Prometheus endpoint exposing metrics data in a format that can be scraped by a Prometheus server is accessible under the path /actuator/prometheus.
A variety of endpoints associated with the deployed application are available to further explore the logs, metrics, and such. You can access them according to the directions here.

Undeploy the application

To undeploy the application, delete the Spring Boot OAM resources.
```
$ kubectl delete -f https://raw.githubusercontent.com/verrazzano/verrazzano/master/examples/springboot-app/springboot-app.yaml -n springboot
$ kubectl delete -f https://raw.githubusercontent.com/verrazzano/verrazzano/master/examples/springboot-app/springboot-comp.yaml -n springboot
```
Delete the namespace springboot after the application pod is terminated.
```
$ kubectl delete namespace springboot
```