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swiftkube/model
Swift Kubernetes API objects
.package(url: "https://github.com/swiftkube/model.git", from: "0.3.3")

Kubernetes 1.18.9 Swift Package Manager macOS + iOS + Linux CI Status

Table of contents

Overview

SwiftkubeModel is a zero-dependency Swift package for Kuberente API objects.

  • ☑ Model structs for all Kuberentes objects
  • Codable support
  • ☑ Closure-based builders for convenient object composition
  • ☑ Type-erased wrappers for Kubernetes resources

Compatibility Matrix

<1.18.9 1.18.9 - 1.18.13 1.19.8
SwiftkubeModel 0.2.x - -
SwiftkubeModel 0.3.x - -
  • Exact match of API objects in both model and the Kubernetes version.
  • - API objects mismatches either due to the removal of old API or the addition of new API. However, everything the model and Kubernetes have in common will work.

Usage

To use the Kubernetes objects just import SwiftkubeModel:

import SwiftkubeModel

let metadata = meta.v1.ObjectMatadata(name: "swiftkube")
let pod = core.v1.Pod(metadata: metadata)

All the objects are namespaced according to their API group and version, e.g. apps.v1.Deployment or networking.v1beta1.Ingress. Which means, that for example rbac.v1.Role and rbac.v1beta1.Role are completely different objects.

Examples

Any Kubernetes object can be constructed directly using the model structs. Here is an example for a Deployment manifest:

let deployment = apps.v1.Deployment(
    metadata: meta.v1.ObjectMeta(
        name: "nginx"
    ),
    spec: apps.v1.DeploymentSpec(
        replicas: 1,
        selector: meta.v1.LabelSelector(
            matchLabels: ["app": "nginx"]
        ),
        template: core.v1.PodTemplateSpec (
            spec: core.v1.PodSpec(
                containers: [
                    core.v1.Container(
                        image: "nginx",
                        name: "nginx",
                    )
                ]
            )
        )
    )
)

Here is a ConfigMap:

let configMap = core.v1.ConfigMap(
    metadata: meta.v1.ObjectMeta(
        name: "config"
    ),
    data: [
        "env": "dev",
        "log_leve": "debug"
    ]
)

A more complete example of a Deployment, that defines Probes, ResourceRequirements, Volumes and VolumeMounts would look something like this:

let deployment = apps.v1.Deployment(
    metadata: meta.v1.ObjectMeta(
        name: "opa",
        namespace: "default"
    ),
    spec: apps.v1.DeploymentSpec(
        replicas: 2,
        selector: meta.v1.LabelSelector(
            matchLabels: ["app": "opa"]
        ),
        template: core.v1.PodTemplateSpec (
            spec: core.v1.PodSpec(
                containers: [
                    core.v1.Container(
                        image: "openpolicyagent/opa",
                        name: "opa",
                        readinessProbe: core.v1.Probe(
                            failureThreshold: 1,
                            httpGet: core.v1.HTTPGetAction(
                                path: "/health",
                                port: 8080
                            ),
                            initialDelaySeconds: 10,
                            periodSeconds: 20,
                            successThreshold: 2,
                            timeoutSeconds: 5
                        ),
                        resources: core.v1.ResourceRequirements(
                            limits: [
                                "ram": "512MB"
                            ],
                            requests: [
                                "ram": "128MB",
                                "cpu": "200m",
                            ]
                        ),
                        volumeMounts: [
                            core.v1.VolumeMount(
                                mountPath: "/etc/test",
                                name: "data"
                            )
                        ]
                    )
                ],
                imagePullSecrets: [
                    core.v1.LocalObjectReference(name: "secret-name")
                ],
                volumes: [
                    core.v1.Volume(
                        name: "data",
                        persistentVolumeClaim: core.v1.PersistentVolumeClaimVolumeSource(
                            claimName: "pvc",
                            readOnly: true
                        )
                    )
                ]
            )
        )
    )
)

Builders

From the above example it is clear, that a certain knowledge of all the subtypes and their API groups is required, in order to comose a complete manifest. Furthermore, Swift doesn't allow arbitrary arguments order.

For this purpose SwiftkubeModel provides simple closure-based builder functions for convenience. All these functions reside under the sk namespace.

:warning: The syntax is not yet finalized and can break many times before v1.0.0 ships. This can also be replaced with Function/Result Builders, which is currently a WIP.

:warning: SwiftkubeModel currently provides conveniece builders only for the most common Kubernetes objects.

The above example would look like this:

let deployment = sk.deployment(name: "opa") {
    $0.metadata = sk.metadata {
        $0.namespace = "default"
    }
    $0.spec = sk.deploymentSpec {
        $0.replicas = 1
        $0.selector = sk.match(labels: ["app": "nginx"])
        $0.template = sk.podTemplate {
            $0.spec = sk.podSpec {
                $0.containers = [
                    sk.container(name: "opa") {
                        $0.image = "openpolicyagent/opa"
                        $0.readinessProbe = sk.probe(action: .httpGet(path: "/health", port: 8080)) {
                            $0.failureThreshold = 1
                            $0.initialDelaySeconds = 10
                            $0.periodSeconds = 20
                            $0.successThreshold = 2
                            $0.failureThreshold = 5
                        }
                        $0.resources = sk.requirements {
                            $0.requests = [
                                "ram": "512MB"
                            ]
                            $0.limits = [
                                "ram": "128MB",
                                "cpu": "200m",
                            ]
                        }
                        $0.volumeMounts = [
                            sk.volumeMount(name: "data", mountPath: "/etc/test")
                        ]
                    }
                ]
                $0.imagePullSecrets = [
                    sk.localObjectReference(name: "secret-name")
                ]
                $0.volumes = [
                    sk.volume(name: "data", from: .persistentVolumeClaim(claimName: "pvc", readOnly: true))
                ]
            }
        }
    }
}

Extensions

In addition to closure-based builders, SwiftkubeModel extends the Model objects with some convenience functions, inspired by cdk8s

core.v1.ConfigMap

  • Populating a ConfigMap
let configMap: core.v1.ConfigMap = sk.configMap(name: "test")

// populate the config map
configMap.add(data: "stuff", forKey: "foo")
configMap.add(binaryData: <binary>, forKey: "foo")
configMap.add(file: URL(fileURLWithPath: "/some/path"), forKey: "foo")
configMap.add(binaryFile: URL(fileURLWithPath: "/some/path"), forKey: "foo")

core.v1.Container

  • Mount a volume in a container
let container: core.v1.Container = ...
let volume: core.v1.Volume = ...

// mount a volume in a container
container.mount(volume: volume, on: "/data")
container.mount(volume: "dataVolume", on: "/data")

core.v1.Namespace

  • Finalizers
let namespace: core.v1.Namespace = ...

// add/remove finalizers
namespace.add(finalizer: "foo")
namespace.remove(finalizer: "foo")

core.v1.Secret

  • Populating a Secret: the values are Base64-encoded automatically
let secret: core.v1.Secret = sk.secret(name: "test")

// populate the secert
configMap.add(data: "stuff", forKey: "foo")
configMap.add(file: URL(fileURLWithPath: "/some/path"), forKey: "foo")

core.v1.Service

  • Server ports on a service
let service: core.v1.Service = ...

// add a service port entry
service.serve(port: 8080, targetPort: 80)

core.v1.ServiceAccount

  • Use secrets
let serviceAccount: core.v1.ServiceAccount = ...

// add an object reference for a secret
serviceAccount.use(imagePullSecret: "pullSecret")
serviceAccount.use(secret: "secret", namespace: "ns")

apps.v1.Deployment

  • Exposing a Deployment
let deployment: apps.v1.Deployment = ...

// expose a deployment instance to create a service
let service = deployment.expose(on: 8080, type: .clusterIP)

Type-erasure

Often when working with Kubernetes the concrete type of the resource is not known or not relevant, e.g. when creating resources from a YAML manifest file. Other times the type or kind of the resource must be derived at runtime given its string representation.

SwiftkubeModel provides a type-erased resource implementation AnyKubernetesAPIResource and its corresponding List-Type AnyKubernetesAPIResourceList in order to tackle these use-cases.

Here are some examples to clarify their purpose:

// Given a JSON string, e.g. at runtime, containing some Kuberenete resource
let str = """
   {
      "apiVersion": "v1",
      "kind": "Pod",
        "metadata": {
          "name": "test",
          "namespace": "ns"
      }
   }
	"""

// We can still decode it without knowing the concrete type
let data = str.data(using: .utf8)!
let resource = try? JSONDecoder().decode(AnyKubernetesAPIResource.self, from: data)

// When encoding the previous instance, it serializes the underlying resource
let data = try? JSONEncoder().encode(resource) 

Installation

To use the SwiftkubeModel in a SwiftPM project, add the following line to the dependencies in your Package.swift file:

.package(name: "SwiftkubeModel", url: "https://github.com/swiftkube/model.git", from: "0.3.0"),

then include it as a dependency in your target:

import PackageDescription

let package = Package(
    // ...
    dependencies: [
        .package(name: "SwiftkubeModel", url: "https://github.com/swiftkube/model.git", from: "0.2.0")
    ],
    targets: [
        .target(name: "<your-target>", dependencies: [
            .product(name: "SwiftkubeModel", package: "SwiftkubeModel"),
        ])
    ]
)

Then run swift build.

License

Swiftkube project is licensed under version 2.0 of the Apache License. See LICENSE for more details.

GitHub

link
Stars: 13
Last commit: 4 days ago

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iOS Software Engineer @ Perry Street Software
Perry Street Software is Jack’d and SCRUFF. We are two of the world’s largest gay, bi, trans and queer social dating apps on iOS and Android. Our brands reach more than 20 million members worldwide so members can connect, meet and express themselves on a platform that prioritizes privacy and security. We invest heavily into SwiftUI and using Swift Packages to modularize the codebase.

Release Notes

SwiftkubeModel 0.3.3
6 weeks ago
  • Add supported platforms for Swift package
  • Add CI for iOS build

Swiftpack is being maintained by Petr Pavlik | @ptrpavlik | @swiftpackco | API