feat: Helm charts created

[Helion55]

About this PR

This PR will add Helm Charts for the application. Deployment, Service, and Ingress manifests are created. The values.yaml file contains all the values for the manifests. NOTES.txt I have left empty because I feel maintainers can describe or change any stuff as required and this will be much more convenient to the end user. 
In the Ingress, I have configured it to use with SSL certificates, and the required values can be filled during the deployment; otherwise, it can be ignored, and the service can be exposed in the classic way. 

Note

1. Deployment, Service, and Ingress manifests are created.
2. values.yaml file have four sections: Common Values, Deployment Values, Service Values, and Ingress Values.
3. Environment variables for deployment are filled using the docker-compose.yaml file.
4. Notes.txt is fully customizable.
5.  Not used the Charts folder as there are no dependencies for this helm deployment.

Feature Added

Solved #32 

[TimoGlastra]

Nice! Thanks for this! Maybe you could add some simple docs on how to use this?

And maybe @jleach should also take a look? I'm not experienced in kubernetes setup

[TimoGlastra]

Should we give these mediator specific names?

[Helion55]

Sure, I will write the docs with the helm commands to install the application.

For the name: and description: I have left it default, but we can change that any time. Also suggest to me any note we should display after the helm deployment; I will write that too.

[TimoGlastra]

It would be good to be able to override all values. (Also wallet_name)

[Helion55]

I have written the values from the docker-compose.yaml file, it should be left with only "{}" this.
Like,
AGENT_NAME: {}
WALLET_NAME: {}
...
...

For reference I have done that. You can override the values as needed or can set the values with helm --set flag during helm install. You can refer to this https://helm.sh/docs/helm/helm_install/

[jleach]

You probably want these to be overridable also:

  AGENT_ENDPOINTS: "https://my-mediator.com,wss://my-mediator.com"

[jleach]

@Helion55 We can start with this although we'll need to make some notable changes. I could list 'em off but I think this would turn into an epic. We can either keep this alive and keep chipping away at it or merge and I can start contributing to the helm charts also. Thoughts @TimoGlastra ?

[Helion55]

Is that fine?

[Helion55]

If other k8s objects are required, I will work on them. So @jleach, if you kindly mention some of the tasks on which I can work, please let me know; this way the whole Helm Chart will be completed soon.

[jleach]

I think we can add the existing health check. Something like:

          livenessProbe:
            httpGet:
              path: /health
              port: http
            initialDelaySeconds: 45
            periodSeconds: 3
          readinessProbe:
            httpGet:
              path: /health
              port: http
            initialDelaySeconds: 45
            timeoutSeconds: 3

[jleach]

Wallet key, postgres password, are better stored in secrets. Let's move them and reverence them accordingly:

          envFrom:
            - secretRef:
                name: {{ include "mediator-agent.fullname" . }}-postgresql-creds
            - secretRef:
                name: {{ include "mediator-agent.fullname" . }}-creds

[jleach]

I think we should add the ability to control resource usage. Able to add that to the deployment?

          resources:
            {{- toYaml .Values.resources | nindent 12 }}

Then add values_dev.yml with the following:

resources:
  requests:
    memory: 256Mi
    cpu: 20m
  limits:
    memory: 256Mi
    cpu: 100m

This way we add different values for dev, test, stage, prod. Whatever different teams want to use.

[jleach]

Always is the default. The best practices is to not put in default values. Let's remove Always.

[jleach]

The mediator needs a caches directory, I'm not 100% sure why but it does. Let's add that as an emptyDir:

      volumes:
        - name: cache-volume
          emptyDir:
            sizeLimit: 1Gi

and

          volumeMounts:
            - name: cache-volume
              mountPath: /.cache

[jleach]

I might add an example of how a secret should be created to work with this helm chart. Not sure what to do with it. We only want it to run when a chart is installed, not updated so for now it can just live in notes unless you know a good way to do this:

---
apiVersion: v1
kind: Secret
metadata:
  name: {{ include "mediator-agent.fullname" . }}-creds
  labels: {{- include "mediator-agent.labels" . | nindent 4}}
type: Opaque
data:
  WALLET_NAME: {{.Values.wallet_user | default "mediator" | b64enc}} 
  WALLET_KEY: {{.Values.wallet_key | default (randAlphaNum 16) | b64enc}}