Table of contents
Overview
SwiftkubeModel is a zero-dependency Swift package for Kuberente API objects.
- Model structs for all Kuberentes objects
-
Codablesupport - Closure-based builders for convenient object composition
- Type-erased wrappers for Kubernetes resources
-
UnstructuredResourcetype for handling any Kubernetes resource
Compatibility Matrix
| <1.18.9 | 1.18.9 - 1.18.13 | 1.19.8 | 1.20.9 | 1.22.7 | |
|---|---|---|---|---|---|
| SwiftkubeModel 0.2.x | - | ✓ | - | - | - |
| SwiftkubeModel 0.3.x | - | - | ✓ | - | - |
| SwiftkubeModel 0.4.x | - | - | - | ✓ | - |
| SwiftkubeModel 0.5.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.
⚠️ 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.
⚠️ SwiftkubeModelcurrently 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) SwiftkubeModel also provides the UnstruturedResource, that is used as fallback for any unknown Kubernetes resource, that can't be determined by its GVK or GVR.
UnstruturedResource allows objects that do not have registered KubernetesAPIResources to be manipulated generically.
This can be used to deal with the API objects from a plug-in or CRDs.
let json = """
{
"apiVersion": "stable.example.com/v1",
"kind": "CronTab",
"metadata": {
"name": "my-new-cron-object",
"namespace": "default"
},
"spec": {
"cronSpec": "* * * * */5",
"image": "my-awesome-cron-image"
}
}
"""
let data = str.data(using: .utf8)!
let cron = try? JSONDecoder().decode(UnstructuredResource.self, from: data)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: "0.4.0"),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: "0.5.0")
],
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.