# I-Ching
The I-Ching (a.k.a. the *Book of Changes*) is an ancient method of divination based on
cleromancy (assigning meaning to the generation of apparently random numbers.) Six numbers
between 6 and 9 are generated in order to create a hexagram, the meaning of which is
contained in the I Ching book.

You can find lots of great information on the 2000+ year history of the I-Ching on
[Wikipedia](https://en.wikipedia.org/wiki/I_Ching)

This app will send an I-Ching horoscope to the pre-configured mailhog instance in configurable intervalls.

This app uses the I-Ching library app https://github.com/Velfi/i-ching.git.

<!--## Configuration
Properties of the app can be configured in the file config.json. It is possible to configure the mail host and port.
It is also possible to configure the intervall of days between the sending of horoscopes and the time of sending. The default is to send one email every seven days at 8 am.-->

## First Start
The app can be deployed by running:

```bash
$     kubectl apply -f deployment.yaml 
```

This will start the deployment of the app in the pod, the service and an ingress for the HTTP frontend server and an ingress for the backend server.
When a pod with the app is initally started, one email will be sent to the configured receiver.

## Backend Server

The backend server is running inside the pod on the address http://localhost:8090/command. If a POST is sent to this address, the server will run the main logic of this app:
An E-Mail with an I-Ching horoscope (provided by the library app) will be sent to the configured email address.

The backend server can be tested from inside the pod by calling 'curl -X POST http://localhost:8090/iching/api/command' from the console.
The backend server has a separate ingress, so API requests can get forwarded to the backend. Also the backend does not need 'rewrite target'.

## HTTP Server

The frontend server is running inside the pod on the address http://localhost:8080/iching. It provides an HTML homepage with a button. Upon pressing the button, the backend server will be called (to send an E-Mail).
The frontend server has a separate ingress from the backend server, since the frontend server needs the 'rewrite target' annotation: So the Frontend is not running in the root folder but using the sub-path 'iching'.

<!--## Testing
The Jest unit tests can be run with

```bash
$     npm test
```
-->