The Kubernetes Fluent Client for Node is a fluent API for the Kubernetes JavaScript Client with some additional logic for Server Side Apply, Watch with retry/signal control, and Field Selectors. In addition to providing a human-friendly API, it also provides a simple way to create and manage resources in the cluster and integrate with K8s in a type-safe way.
To install the Kubernetes Fluent Client, run the following command:
npm install kubernetes-fluent-client
See below for some example uses of the library.
import { K8s, kind } from "kubernetes-fluent-client";
// Let's create a random namespace to work in
const namespace = "my-namespace" + Math.floor(Math.random() * 1000);
// This will be called after the resources are created in the cluster
async function demo() {
// Now, we can use the fluent API to query for the resources we just created
// You can use watch to monitor resources in the cluster and react to changes
const watcher = K8s(kind.Pod).Watch((pod, phase) => {
console.log(`Pod ${pod.metadata?.name} is ${phase}`);
});
// This will run until the process is terminated or the watch is aborted
await watcher.start();
// Let's abort the watch after 5 seconds
setTimeout(watcher.close, 5 * 1000);
// Passing the name to Get() will return a single resource
const ns = await K8s(kind.Namespace).Get(namespace);
console.log(ns);
// This time we'll use the InNamespace() method to filter the results by namespace and name
const cm = await K8s(kind.ConfigMap).InNamespace(namespace).Get("my-configmap");
console.log(cm);
// If we don't pass a name to Get(), we'll get a list of resources as KubernetesListObject
// The matching resources will be in the items property
const pods = await K8s(kind.Pod).InNamespace(namespace).Get();
console.log(pods);
// Now let's delete the resources we created, you can pass the name to Delete() or the resource itself
await K8s(kind.Namespace).Delete(namespace);
// Let's use the field selector to find all the running pods in the cluster
const runningPods = await K8s(kind.Pod).WithField("status.phase", "Running").Get();
runningPods.items.forEach(pod => {
console.log(`${pod.metadata?.namespace}/${pod.metadata?.name} is running`);
});
// Get logs from a Deployment named "nginx" in the namespace
const logs = await K8s(kind.Deployment).InNamespace(namespace).Logs("nginx");
console.log(logs);
}
// Create a few resources to work with: Namespace, ConfigMap, and Pod
Promise.all([
// Create the namespace
K8s(kind.Namespace).Apply({
metadata: {
name: namespace,
},
}),
// Create the ConfigMap in the namespace
K8s(kind.ConfigMap).Apply({
metadata: {
name: "my-configmap",
namespace,
},
data: {
"my-key": "my-value",
},
}),
// Create the Pod in the namespace
K8s(kind.Pod).Apply({
metadata: {
name: "my-pod",
namespace,
},
spec: {
containers: [
{
name: "my-container",
image: "nginx",
},
],
},
}),
])
.then(demo)
.catch(err => {
console.error(err);
});
To chat with other users & see some examples of the fluent client in active use, go to Kubernetes Slack and join #pepr
channel.