Hello Config World Helidon

This example is a Helidon-based service that returns a “HelloConfig World” response when invoked. The application configuration uses a Kubernetes ConfigMap, instead of the default, microprofile properties file.

Before you begin

Install Verrazzano by following the installation instructions.

NOTE: The Hello World Helidon configuration example application deployment files are contained in the Verrazzano project located at <VERRAZZANO_HOME>/examples/helidon-config, where <VERRAZZANO_HOME> is the root of the Verrazzano project.

Deploy the Hello Config World Helidon application

Create a namespace for the application and add a label identifying the namespace as managed by Verrazzano.

$ kubectl create namespace helidon-config
$ kubectl label namespace helidon-config verrazzano-managed=true istio-injection=enabled

To deploy the application, apply the helidon-config OAM resources.

$ kubectl apply -f https://raw.githubusercontent.com/verrazzano/verrazzano/v1.0.4/examples/helidon-config/helidon-config-comp.yaml
$ kubectl apply -f https://raw.githubusercontent.com/verrazzano/verrazzano/v1.0.4/examples/helidon-config/helidon-config-app.yaml

Wait for the application to be ready.

$ kubectl wait \
   --for=condition=Ready pods \
   --all -n helidon-config \
   --timeout=300s

Explore the application

The Hello World Helidon configuration example implements a REST API endpoint, /config, which returns a message {"message":"HelloConfig World!"} when invoked.

NOTE: The following instructions assume that you are using a Kubernetes environment such as OKE. Other environments or deployments may require alternative mechanisms for retrieving addresses, ports, and such.

Follow these steps to test the endpoints:

Get the generated host name for the application.

$ HOST=$(kubectl get gateway helidon-config-helidon-config-appconf-gw \
     -n helidon-config \
     -o jsonpath={.spec.servers[0].hosts[0]})
$ echo $HOST
helidon-config-appconf.helidon-config.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
11.22.33.44

Access the application:
- Using the command line
```
$ curl -sk \
   -X GET \
   https://${HOST}/config \
   --resolve ${HOST}:443:${ADDRESS}
{"message":"HelloConfig World!"}
```
  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 helidon-config.example.com
```
  Then you can access the application in a browser at https://<host>/config.
- 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 edit the helidon-config-app.yaml file to use the appropriate value under the hosts section (such as yourhost.your.domain), before deploying the helidon-config application.
  - Then, you can use a browser to access the application at https://<yourhost.your.domain>/config.

A variety of endpoints associated with the deployed application, are available to further explore the logs, metrics, and such.

Accessing them may require the following:

Run this command to get the password that was generated for the telemetry components:

$ kubectl get secret \
   --namespace verrazzano-system verrazzano \
   -o jsonpath={.data.password} | base64 \
   --decode; echo

The associated user name is verrazzano.

You will have to accept the certificates associated with the endpoints.

You can retrieve the list of available ingresses with following command:

$ kubectl get ing -n verrazzano-system
NAME                         CLASS    HOSTS                                                    ADDRESS          PORTS     AGE
verrazzano-console-ingress   <none>   verrazzano.default.140.238.94.217.nip.io                 140.238.94.217   80, 443   7d2h
vmi-system-api               <none>   api.vmi.system.default.140.238.94.217.nip.io             140.238.94.217   80, 443   7d2h
vmi-system-es-ingest         <none>   elasticsearch.vmi.system.default.140.238.94.217.nip.io   140.238.94.217   80, 443   7d2h
vmi-system-grafana           <none>   grafana.vmi.system.default.140.238.94.217.nip.io         140.238.94.217   80, 443   7d2h
vmi-system-kibana            <none>   kibana.vmi.system.default.140.238.94.217.nip.io          140.238.94.217   80, 443   7d2h
vmi-system-prometheus        <none>   prometheus.vmi.system.default.140.238.94.217.nip.io      140.238.94.217   80, 443   7d2h

Using the ingress host information, some of the endpoints available are:

Description	Address	Credentials
Kibana	`https://[vmi-system-kibana ingress host]`	`verrazzano`/`telemetry-password`
Grafana	`https://[vmi-system-grafana ingress host]`	`verrazzano`/`telemetry-password`
Prometheus	`https://[vmi-system-prometheus ingress host]`	`verrazzano`/`telemetry-password`

Troubleshooting

Verify that the application configuration, domain, and ingress trait all exist.

$ kubectl get ApplicationConfiguration -n helidon-config
$ kubectl get IngressTrait -n helidon-config

Verify that the helidon-config service pods are successfully created and transition to the READY state. Note that this may take a few minutes and that you may see some of the services terminate and restart.
```
 $ kubectl get pods -n helidon-config

 NAME                                      READY   STATUS    RESTARTS   AGE
 helidon-config-deployment-676d97c7d4-wkrj2   3/3     Running   0          5m39s
```

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