controller-utils

README

controller-utils

This is a library of Go functions to assist in building Kubernetes Controllers.

The pkg/controller package contains the main functionality. pkg/log contains helpers around logging. You can pass in a logr object to control the logs of this library.

Basic Usage

package main

import (
	"context"
	"fmt"

	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/client-go/dynamic"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/restmapper"
	ctrl "sigs.k8s.io/controller-runtime"

	"github.com/fairwindsops/controller-utils/pkg/controller"
)

func main() {
	dynamic, restMapper, err := getKubeClient()
	if err != nil {
		panic(err)
	}
	client := controller.Client{
		Context:    context.TODO(),
		Dynamic:    dynamic,
		RESTMapper: restMapper,
	}
	workloads, err := client.GetAllTopControllersSummary("")
	if err != nil {
		panic(err)
	}
	for _, workload := range workloads {
		ctrl := workload.TopController
		fmt.Println()
		fmt.Printf("Workload: %s/%s/%s\n", ctrl.GetKind(), ctrl.GetNamespace(), ctrl.GetName())
		fmt.Printf("  num pods: %d\n", workload.PodCount)
		fmt.Printf("  running: %d\n", workload.RunningPodCount)
		fmt.Printf("  podSpec: %#v\n", workload.PodSpec)
	}
}

func getKubeClient() (dynamic.Interface, meta.RESTMapper, error) {
	var restMapper meta.RESTMapper
	var dynamicClient dynamic.Interface
	kubeConf, configError := ctrl.GetConfig()
	if configError != nil {
		return dynamicClient, restMapper, configError
	}

	api, err := kubernetes.NewForConfig(kubeConf)
	if err != nil {
		return dynamicClient, restMapper, err
	}

	dynamicClient, err = dynamic.NewForConfig(kubeConf)
	if err != nil {
		return dynamicClient, restMapper, err
	}

	resources, err := restmapper.GetAPIGroupResources(api.Discovery())
	if err != nil {
		return dynamicClient, restMapper, err
	}
	restMapper = restmapper.NewDiscoveryRESTMapper(resources)
	return dynamicClient, restMapper, nil
}

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