# Mirko, an abstraction layer for hscloud kubernetes services.

local kube = import "kube.libsonnet";

{
    Environment(name): {
        local env = self,
        local cfg = env.cfg,
        cfg:: {
            name: name,
            namespace: cfg.name,
        },

        namespace: kube.Namespace(cfg.namespace),

        components: {}, // type: mirko.Component

        // Currently hardcoded!
        // This might end up being something passed part of kubecfg evaluation,
        // when we get to supporting multiple/federated clusters.
        // For now, this is goog enough.
        pkiRealm:: "hswaw.net",
        pkiClusterFQDN:: "k0.hswaw.net",

        // Generate an ingress if we have any public ports.
        publicHTTPPorts:: std.flattenArrays([
            [
                {
                    local component = env.components[c],

                    service: component.svc,
                    port: component.cfg.ports.publicHTTP[p].port,
                    dns: component.cfg.ports.publicHTTP[p].dns,
                    // Extra headers to set.
                    // BUG(q3k): these headers are applied to all components in the environment!
                    // We should be splitting up ingresses where necessary to combat this.
                    setHeaders: [],
                    // Extra paths to add to ingress. These are bare HTTPIngressPaths.
                    extraPaths: component.cfg.extraPaths,
                }
                for p in std.objectFields(env.components[c].cfg.ports.publicHTTP)
            ]
            for c in std.objectFields(env.components)
        ]),

        ingress: if std.length(env.publicHTTPPorts) > 0 then kube.Ingress("mirko-public") {
            metadata+: {
                namespace: env.cfg.namespace,
                labels: {
                    "app.kubernetes.io/name": cfg.name,
                    "app.kubernetes.io/managed-by": "kubecfg-mirko",
                    "app.kubernetes.io/component": cfg.name,
                    "mirko.hscloud.hackerspace.pl/environment": env.cfg.name,
                    "mirko.hscloud.hackerspace.pl/component": "mirko-public-ingress",
                },
                annotations+: {
                    "kubernetes.io/tls-acme": "true",
                    "certmanager.k8s.io/cluster-issuer": "letsencrypt-prod",
                    [if env.ingressServerSnippet != null]: "nginx.ingress.kubernetes.io/server-snippet": env.ingressServerSnippet,
                    [if std.length(env.extraHeaders) > 0 then "nginx.ingress.kubernetes.io/configuration-snippet"]:
                        std.join("\n", ["proxy_set_header %s;" % [h] for h in env.extraHeaders]),
                },
            },
            spec+: {
                tls: [
                    {
                        hosts: [p.dns for p in env.publicHTTPPorts],
                        secretName: "mirko-public-tls",
                    },
                ],
                rules: [
                    {
                        host: p.dns,
                        http: {
                            paths: [
                                { path: "/", backend: { serviceName: p.service.metadata.name, servicePort: p.port }},
                            ] + p.extraPaths,
                        },
                    }
                    for p in env.publicHTTPPorts
                ],
            },
        } else {},

        // Nginx Ingress Controller server configuration snippet to add.
        ingressServerSnippet:: null,

        // Extra request headers to add to ingress
        extraHeaders:: std.flattenArrays([
            std.flattenArrays([

                local portc = env.components[c].cfg.ports.publicHTTP[p];
                if std.objectHas(portc, "setHeaders") then portc.setHeaders else []
                for p in std.objectFields(env.components[c].cfg.ports.publicHTTP)
            ])
            for c in std.objectFields(env.components)
        ]),
    },

    Component(env, name): {
        local component = self,
        local cfg = component.cfg,

        makeName(suffix):: "%s%s%s" % [cfg.prefix, cfg.name, suffix],
        makeNameGlobal(suffix):: "%s-%s" % [env.cfg.namespace, component.makeName(suffix)],

        metadata:: {
            namespace: env.cfg.namespace,
            labels: {
                "app.kubernetes.io/name": env.cfg.name,
                "app.kubernetes.io/managed-by": "kubecfg-mirko",
                "app.kubernetes.io/component": cfg.name,
                "mirko.hscloud.hackerspace.pl/environment": env.cfg.name,
                "mirko.hscloud.hackerspace.pl/component": cfg.name,
            },
        },


        # Tunables for users.
        cfg:: {
            name: name,

            prefix:: "",
            image:: env.image,
            volumes:: {},
            containers:: {
                main: cfg.container,
            }, 
            nodeSelector: null,
            securityContext: {},
            container:: error "container(s) must be set",
            ports:: {
                publicHTTP: {}, // name -> { port: no, dns: fqdn }
                grpc: { main: 4200 }, // name -> port no
            },
            extraPaths:: [],
        },

        allPorts:: {
            ['grpc-' + p]: cfg.ports.grpc[p]
            for p in std.objectFields(cfg.ports.grpc)
        } + {
            ['pubhttp-' + p] : cfg.ports.publicHTTP[p].port
            for p in std.objectFields(cfg.ports.publicHTTP)
        },

        Container(name):: kube.Container(component.makeName(name)) {
            image: cfg.image,
            volumeMounts_: {
                pki: { mountPath: "/mnt/pki" },
            },
            ports_: {
                [p]: { containerPort: component.allPorts[p] }
                for p in std.objectFields(component.allPorts)
            },
            resources: {
                requests: {
                    cpu: "25m",
                    memory: "64Mi",
                },
                limits: {
                    cpu: "500m",
                    memory: "128Mi",
                },
            },
        },

        GoContainer(name, binary):: component.Container(name) {
            command: [
                binary,
                "-hspki_realm", env.pkiRealm,
                "-hspki_cluster", env.pkiClusterFQDN,
                "-hspki_tls_ca_path", "/mnt/pki/ca.crt",
                "-hspki_tls_certificate_path", "/mnt/pki/tls.crt",
                "-hspki_tls_key_path", "/mnt/pki/tls.key",
                "-logtostderr",
                "-listen_address", "0.0.0.0:4200",
            ],
        },

        deployment: kube.Deployment(component.makeName("-main")) {
            metadata+: component.metadata,
            spec+: {
                template+: {
                    spec+: {
                        volumes_: {
                            pki: {
                                secret: { secretName: component.pki.cert.spec.secretName },
                            },
                        } + cfg.volumes,
                        containers_: cfg.containers,
                        nodeSelector: cfg.nodeSelector,

                        serviceAccountName: component.sa.metadata.name,
                        securityContext: cfg.securityContext,
                    },
                },
            },
        },

        svc: kube.Service(component.makeName("")) { // No suffix, name part of DNS entry.
            metadata+: component.metadata,
            target_pod:: component.deployment.spec.template,
            spec+: {
                ports: [
                    {
                        name: p,
                        port: component.allPorts[p],
                        targetPort: component.allPorts[p],
                    }
                    for p in std.objectFields(component.allPorts)
                ],
            },
        },

        sa: kube.ServiceAccount(component.makeName("-main")) {
            metadata+: component.metadata,
        },

        pki: {
            cert: kube.Certificate(component.makeName("-cert")) {
                metadata+: component.metadata,
        
                spec: {
                    secretName: component.makeName("-cert"),
                    duration: "35040h0m0s", // 4 years
                    issuerRef: {
                        // Contract with cluster/lib/pki.libsonnet.
                        name: "pki-ca",
                        kind: "ClusterIssuer",
                    },
                    commonName: "%s.%s.svc.%s" % [component.svc.metadata.name, component.svc.metadata.namespace, env.pkiClusterFQDN ],
                    dnsNames: [
                        "%s" % [component.svc.metadata.name ],
                        "%s.%s" % [component.svc.metadata.name, component.svc.metadata.namespace ],
                        "%s.%s.svc" % [component.svc.metadata.name, component.svc.metadata.namespace ],
                        "%s.%s.svc.cluster.local" % [component.svc.metadata.name, component.svc.metadata.namespace ],
                        "%s.%s.svc.%s" % [component.svc.metadata.name, component.svc.metadata.namespace, env.pkiClusterFQDN ],
                    ],
                },
            },
        },
    },
}