# this is libjsonnet library for kubernetes related things
local kube = import '../../../kube/kube.libsonnet';

{
    local shells = self,
    local cfg = shells.cfg,

    # namespace defining parameters used by other functions
    # double colon "::" prevents it from appearing in output file
    cfg:: {
        namespace: "personal-vuko",
        appName: "three-shell-system",
        domain: "shells.vuko.pl",

        nginx_tag: "latest",
        nginx_image: "nginxinc/nginx-unprivileged:stable-alpine",

        storageClassName: "waw-hdd-redundant-2",

        resources: {
            requests: {
                cpu: "25m",
                memory: "50Mi",
            },
            limits: {
                cpu: "100m",
                memory: "200Mi",
            },
        },
    },

    # kubernete namespace personal-${name} for personal usage
    namespace: kube.Namespace(cfg.namespace),

    # function used for configuring components metatada
    metadata(component):: {
        namespace: cfg.namespace,
        labels: {
            "app.kubernetes.io/name": cfg.appName,
            "app.kubernetes.io/managed-by": "kubecfg",
            "app.kubernetes.io/component": component,
        },
    },
    
    # component - persistant (non volatile) memory
    # https://kubernetes.io/docs/concepts/storage/persistent-volumes/
    dataVolume: kube.PersistentVolumeClaim("html-data") {
        # override default PersistentVolumeClaim metatada with values defined
        # in medadata function prevoiusly created
        # "+" sign before means override
        metadata+: shells.metadata("html-data"),
        spec+: {
            storageClassName: cfg.storageClassName,
            # can be connected to multiple containers
            accessModes: [ "ReadWriteMany" ],
            resources: {
                requests: {
                    # amount of storage space: 500Mb
                    storage: "500Mi",
                },
            },
        },
    },

    # deployment declares pods
    # https://kubernetes.io/docs/concepts/workloads/controllers/deployment/
    deployment: kube.Deployment("shells") {
        metadata+: shells.metadata("shells"),
        spec+: {
            replicas: 1,
            template+: {
                spec+: {
                    # names ending with _ have special meaning in this context
                    # this is specified in ../../../kube/kube.upstream.jsonnet
                    # volumes_ { key: { ... } } is converted to volumes [{ name: key, ... }]
                    volumes_: {
                        # sftp container host keys secrets saved to kubernetes semi-manually using create-secrets.py
                        # https://kubernetes.io/docs/concepts/configuration/secret/
                        host_keys: { secret: { secretName: "shells-ssh-host-key-bd65mg4gbt" } },
                        # sftp container authorized_keys saved to kubernetes using command:
                        # kubectl -n personal-vuko create secret generic shells-ssh-authorized-keys --from-file="authorized_keys=${HOME}/.ssh/id_ed25519.pub"
                        authorized_keys: { secret: { secretName: "shells-ssh-authorized-keys", defaultMode: 256 } },
                        # to use created volume in deployment we need to claim it
                        html: kube.PersistentVolumeClaimVolume(shells.dataVolume),
                    },
                    # here are containers defined
                    # when they are defined in one deployment 
                    containers_: {
                        shells: kube.Container("nginx") {
                            image: cfg.nginx_image,
                            ports_: {
                                http: { containerPort: 80 },
                            },
                            resources: cfg.resources,
                            volumeMounts_: {
                                html: { mountPath: "/usr/share/nginx/html" },
                            },
                        },
                        sftp: kube.Container("sftp") {
                            image: "registry.k0.hswaw.net/vuko/hs-shells-sftp:latest",
                            ports_: {
                                sftp: { containerPort: 2222 },
                            },
                            command: [ "/bin/start" ],
                            resources: cfg.resources,
                            securityContext: {
                                # specify uid of user running command
                                runAsUser: 1,
                            },
                            volumeMounts_: {
                                # here volumes defined in volumes_ can be mounted
                                host_keys: { mountPath: "/etc/ssh/host" },
                                authorized_keys: { mountPath: "/etc/ssh/auth" },
                                html: { mountPath: "/data" },
                            },
                        },
                    },
                },
            },
        },
    },

    # defining a service of type LoadBancer gives you acces from internet
    # run: kubectl -n personal-${user} get services to see ip address
    svc: kube.Service("shells") {
        metadata+: shells.metadata("shells"),
        target_pod:: shells.deployment.spec.template,
        spec+: {
            ports: [
                { name: "http", port: 80, targetPort: 8080, protocol: "TCP" },
                { name: "sftp", port: 22, targetPort: 2222, protocol: "TCP" },
            ],
            type: "LoadBalancer",
            externalTrafficPolicy: "Local",
        },
    },

    # ingress creates VirtualHost on ingress.k0.hswaw.net forwaring http(s)
    # requests to your domain to specified Pod/container
    ingress: kube.Ingress("frontend") {
        metadata+: shells.metadata("frontend") {
            annotations+: {
                "kubernetes.io/tls-acme": "true",
                "certmanager.k8s.io/cluster-issuer": "letsencrypt-prod",
            },
        },
        spec+: {
            tls: [
                { hosts: [cfg.domain], secretName: "shells-frontend-tls"}
            ],
            rules: [
                {
                    host: cfg.domain,
                    http: {
                        paths: [
                            { path: "/", backend: shells.svc.name_port },
                        ],
                    },
                },
            ],
        },
    },
}