/
groupcache.go
104 lines (83 loc) · 2.56 KB
/
groupcache.go
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package main
import (
"context"
"log"
"net/http"
"time"
"github.com/mailgun/groupcache/v2"
"github.com/prometheus/client_golang/prometheus"
"github.com/udhos/groupcache_exporter"
"github.com/udhos/groupcache_exporter/groupcache/mailgun"
"github.com/udhos/kube/kubeclient"
"github.com/udhos/kubegroup/kubegroup"
)
func startGroupcache(app *application) {
//
// create groupcache pool
//
myURL, errURL := kubegroup.FindMyURL(app.config.groupCachePort)
if errURL != nil {
log.Fatalf("my URL: %v", errURL)
}
log.Printf("groupcache my URL: %s", myURL)
pool := groupcache.NewHTTPPoolOpts(myURL, &groupcache.HTTPPoolOptions{})
//
// start groupcache server
//
app.serverGroupCache = &http.Server{Addr: app.config.groupCachePort, Handler: pool}
go func() {
log.Printf("groupcache server: listening on %s", app.config.groupCachePort)
err := app.serverGroupCache.ListenAndServe()
log.Printf("groupcache server: exited: %v", err)
}()
//
// start watcher for addresses of peers
//
clientsetOpt := kubeclient.Options{DebugLog: app.config.kubegroupDebug}
clientset, errClientset := kubeclient.New(clientsetOpt)
if errClientset != nil {
log.Fatalf("startGroupcache: kubeclient: %v", errClientset)
}
options := kubegroup.Options{
Client: clientset,
LabelSelector: app.config.kubegroupLabelSelector,
Pool: pool,
GroupCachePort: app.config.groupCachePort,
MetricsRegisterer: prometheus.DefaultRegisterer,
MetricsGatherer: prometheus.DefaultGatherer,
MetricsNamespace: "",
Debug: app.config.kubegroupDebug,
}
if _, errKg := kubegroup.UpdatePeers(options); errKg != nil {
log.Fatalf("kubegroup: %v", errKg)
}
//
// create cache
//
// https://talks.golang.org/2013/oscon-dl.slide#46
//
// 64 MB max per-node memory usage
app.cache = groupcache.NewGroup("gateways", app.config.groupCacheSizeBytes, groupcache.GetterFunc(
func(ctx context.Context, gatewayName string, dest groupcache.Sink) error {
out, _, errID := repoGetMultiple(ctx, app, gatewayName)
if errID != nil {
return errID
}
var expire time.Time // zero value for expire means no expiration
if app.config.groupCacheExpire != 0 {
expire = time.Now().Add(app.config.groupCacheExpire)
}
dest.SetString(out.GatewayID, expire)
return nil
}))
//
// expose prometheus metrics for groupcache
//
mailgun := mailgun.New(app.cache)
labels := map[string]string{
//"app": appName,
}
namespace := ""
collector := groupcache_exporter.NewExporter(namespace, labels, mailgun)
prometheus.MustRegister(collector)
}