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main.go
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main.go
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package main
import (
"context"
"flag"
"fmt"
"math/rand"
"net/http"
"os"
"path/filepath"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/watch"
"k8s.io/client-go/kubernetes"
_ "k8s.io/client-go/plugin/pkg/client/auth"
"k8s.io/client-go/rest"
"k8s.io/client-go/tools/cache"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/client-go/util/homedir"
"github.com/snebel29/kooper/log"
"github.com/snebel29/kooper/monitoring/metrics"
"github.com/snebel29/kooper/operator/controller"
"github.com/snebel29/kooper/operator/handler"
"github.com/snebel29/kooper/operator/retrieve"
)
const (
metricsPrefix = "metricsexample"
metricsAddr = ":7777"
prometheusBackend = "prometheus"
)
var (
metricsBackend string
)
func initFlags() error {
fg := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
fg.StringVar(&metricsBackend, "metrics-backend", "prometheus", "the metrics backend to use")
return fg.Parse(os.Args[1:])
}
// sleep will sleep randomly from 0 to 1000 milliseconds.
func sleepRandomly() {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
sleepMS := r.Intn(10) * 100
time.Sleep(time.Duration(sleepMS) * time.Millisecond)
}
// errRandomly will will err randomly.
func errRandomly() error {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
if r.Intn(10)%3 == 0 {
return fmt.Errorf("random error :)")
}
return nil
}
// creates prometheus recorder and starts serving metrics in background.
func createPrometheusRecorder(logger log.Logger) metrics.Recorder {
// We could use also prometheus global registry (the default one)
// prometheus.DefaultRegisterer instead of creating a new one
reg := prometheus.NewRegistry()
m := metrics.NewPrometheus(reg)
// Start serving metrics in background.
h := promhttp.HandlerFor(reg, promhttp.HandlerOpts{})
go func() {
logger.Infof("serving metrics at %s", metricsAddr)
http.ListenAndServe(metricsAddr, h)
}()
return m
}
func getMetricRecorder(backend string, logger log.Logger) (metrics.Recorder, error) {
switch backend {
case prometheusBackend:
logger.Infof("using Prometheus metrics recorder")
return createPrometheusRecorder(logger), nil
}
return nil, fmt.Errorf("wrong metrics backend")
}
func main() {
// Initialize logger.
log := &log.Std{}
// Init flags.
if err := initFlags(); err != nil {
log.Errorf("error parsing arguments: %s", err)
os.Exit(1)
}
// Get k8s client.
k8scfg, err := rest.InClusterConfig()
if err != nil {
// No in cluster? letr's try locally
kubehome := filepath.Join(homedir.HomeDir(), ".kube", "config")
k8scfg, err = clientcmd.BuildConfigFromFlags("", kubehome)
if err != nil {
log.Errorf("error loading kubernetes configuration: %s", err)
os.Exit(1)
}
}
k8scli, err := kubernetes.NewForConfig(k8scfg)
if err != nil {
log.Errorf("error creating kubernetes client: %s", err)
os.Exit(1)
}
// Create our retriever so the controller knows how to get/listen for pod events.
retr := &retrieve.Resource{
Object: &corev1.Pod{},
ListerWatcher: &cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
return k8scli.CoreV1().Pods("").List(options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
return k8scli.CoreV1().Pods("").Watch(options)
},
},
}
// Our domain logic that will print every add/sync/update and delete event we .
hand := &handler.HandlerFunc{
AddFunc: func(_ context.Context, obj runtime.Object) error {
sleepRandomly()
return errRandomly()
},
DeleteFunc: func(_ context.Context, s string) error {
sleepRandomly()
return errRandomly()
},
}
// Create the controller that will refresh every 30 seconds.
m, err := getMetricRecorder(metricsBackend, log)
if err != nil {
log.Errorf("errors getting metrics backend: %s", err)
os.Exit(1)
}
cfg := &controller.Config{
Name: "metricsControllerTest",
}
ctrl := controller.New(cfg, hand, retr, nil, nil, m, log)
// Start our controller.
stopC := make(chan struct{})
if err := ctrl.Run(stopC); err != nil {
log.Errorf("error running controller: %s", err)
os.Exit(1)
}
os.Exit(0)
}