kwait

kwait

🚀 A simple, yet powerful Go library and CLI tool to wait for Kubernetes resources to enter the desired state. 🚀

Entirely inspired by the amazing k8s-wait-for project. The cli and featureset of kwait is designed to be a superset of k8s-wait-for's work with the power of Go!

Features

✅ Supports waiting for Pods, Services, Deployments and Jobs ✅ Provides additional wait modes for Pods and Jobs ✅ Can be used as a library or a standalone CLI tool ✅ Compatible with Kubernetes versions >= 1.24

Installation

go get -u github.com/devlincashman/kwait/cmd/kwait

Usage

CLI

The kwait CLI tool allows you to wait for Kubernetes resources to become ready. Here's an overview of the available flags:

Usage of kwait:
  -kind string
        Kind of the Kubernetes resource (e.g., pod, service, job, deployment).
  -l string
        Label selector for the Kubernetes resource.
  -n string
        Kubernetes namespace for the resource. (default "default")
  -name string
        Name of the Kubernetes resource.

To wait for a resource to become ready, simply run the kwait program and specify the resource type, name, and (optionally) a label selector. For example, to wait for a deployment named my-deployment in the my-namespace namespace to become ready, run:

kwait -n my-namespace -kind deployment -name my-deployment

Examples

Wait for all pods with a following label to enter 'Ready' state: kwait pod -lapp=example

Wait for all selected pods to enter the 'Ready' state:

kwait pod -l"release in (develop)"

Wait for all pods with a following label to enter 'Ready' or 'Error' state:

kwait pod-we -lapp=example

Wait for at least one pod to enter the 'Ready' state, even when the other ones are in 'Error' state:

kwait pod-wr -lapp=example

Wait for all the pods in that job to have a 'Succeeded' state:

kwait job examplejob

Wait for all the pods in that job to have a 'Succeeded' or 'Failed' state:

kwait job-we examplejob

Wait for at least one pod in that job to have 'Succeeded' state, does not mind some 'Failed' ones:

kwait job-wr examplejob

The program will wait until the resource exists and is ready or until it times out or fails a condition.

Supported Resource Types

The kwait program supports the following Kubernetes resource types:

• 🚀 Pods
• 🚀 Services
• 🚀 Deployments
• 🚀 Jobs

To wait for a resource of a specific type, use the -kind flag followed by the name of the resource type (e.g., pod, service, etc.).

Library

The kwait package can also be used as a library to wait for Kubernetes resources in your own Go programs. To use the package, simply import it and create a k8s.Resource object with the appropriate k8s.ResourceWatcher and k8s.ResourceReadyChecker implementations.

import (
    "github.com/devlincashman/kwait/internal/k8s"
    "k8s.io/apimachinery/pkg/runtime"
)

func main() {
    // Create a Kubernetes client
    clientset, err := k8s.NewClient()
    if err != nil {
        panic(err)
    }

    // Create a DeploymentResource
    deploymentResource := k8s.NewDeploymentResource(clientset, "my-namespace")

    // Create a Resource object
    resource := k8s.Resource{
        Watcher:      deploymentResource,
        ReadyChecker: deploymentResource,
    }

    // Wait for the deployment to become ready
    err = resource.WaitForReady("my-namespace", "my-deployment", "")
    if err != nil {
        panic(err)
    }
}