main.go

// Kcount counts Kubernetes objects across namespaces and clusters.
package main

import (
	"flag"
	"log"
	"os"
	"os/user"
	"path/filepath"
	"strings"
	"time"
)

func main() {
	flags := parseFlags()

	if !flags.daemon { // running as CLI app
		log.SetFlags(0)
		log.SetPrefix(os.Args[0] + ": ")
	}

	kubeconfigs, err := getKubeconfigs()
	if err != nil {
		log.Fatalf("getting kubeconfigs: %v", err)
	}

	clusters, err := Clusters(kubeconfigs, flags.allNamespaces, flags.namespace)
	if err != nil {
		log.Fatalf("getting cluster config from %s: %v", strings.Join(kubeconfigs, ", "), err)
	}

	if len(clusters) == 0 {
		log.Fatal("run in cluster, create $HOME/.kube/config, set KUBECONFIG or supply at least one kubeconfig")
	}

	if flags.daemon {
		go func() {
			for {
				counts := CountObjectsAcrossClusters(clusters, flags)
				for _, count := range counts {
					objectsCount.WithLabelValues(count.Cluster, count.Namespace, count.LabelSelector, count.Kind).Set(float64(count.Count))
					if flags.age {
						objectsNewest.WithLabelValues(count.Cluster, count.Namespace, count.LabelSelector, count.Kind).Set(float64(count.Newest.Unix()))
						objectsOldest.WithLabelValues(count.Cluster, count.Namespace, count.LabelSelector, count.Kind).Set(float64(count.Oldest.Unix()))
					}
				}
				time.Sleep(2 * time.Second)
			}
		}()
		addr, urlPath := ":2112", "/metrics"
		log.Printf("exposing Prometheus metrics at %s%s", addr, urlPath)
		log.Fatal(exposeMetrics(addr, urlPath))
	} else { // running as CLI app
		counts := CountObjectsAcrossClusters(clusters, flags)
		counts.Sort()
		counts.Print(flags)
	}
}

// getKubeconfigs returns one or more kubeconfigs from command line arguments or
// from KUBECONFIG environment variable or from $HOME/.kube/config (in that
// order of preference).
func getKubeconfigs() ([]string, error) {
	kubeconfigs := flag.Args()

	if len(kubeconfigs) == 0 {
		// KUBECONGIG can hold multiple kubeconfigs (separated by : on Linux/Mac)
		for _, k := range strings.Split(os.Getenv("KUBECONFIG"), ":") {
			if k != "" {
				kubeconfigs = append(kubeconfigs, k)
			}
		}
	}

	if len(kubeconfigs) == 0 {
		usr, err := user.Current()
		if err != nil {
			return nil, err
		}
		confFile := filepath.Join(usr.HomeDir, ".kube", "config")
		if _, err := os.Stat(confFile); err == nil { // check file exists
			kubeconfigs = append(kubeconfigs, confFile)
		}
	}

	return kubeconfigs, nil
}