Move static scheduler initialization out of module init()

Having call to algorithmprovider.ApplyFeatureGates() in module init
function was problematic as the mathod calls out to klog.Infof().
The call to klog.Infof() was then happening before klog related
application flags were parsed which resulted in klog misbehavior.
See kubernetes/klog#67.

Author: losipiuk

cluster-autoscaler/simulator/predicates.go

@@ -19,6 +19,7 @@ package simulator
 import (
 	"fmt"
 	"strings"
+	"sync"
 
 	apiv1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -44,6 +45,13 @@ const (
 	affinityPredicateName = "MatchInterPodAffinity"
 )
 
+var (
+	// initMutex is used for guarding static initialization.
+	staticInitMutex sync.Mutex
+	// statiInitHappened denotes if static initialization happened.
+	staticInitDone bool
+)
+
 // PredicateInfo assigns a name to a predicate
 type PredicateInfo struct {
 	Name      string
@@ -62,13 +70,21 @@ type PredicateChecker struct {
 // There are no const arrays in Go, this is meant to be used as a const.
 var priorityPredicates = []string{"PodFitsResources", "PodToleratesNodeTaints", "GeneralPredicates", "ready"}
 
-func init() {
+func staticInitIfNeeded() {
+	staticInitMutex.Lock()
+	defer staticInitMutex.Unlock()
+
+	if staticInitDone {
+		return
+	}
+
 	// This results in filtering out some predicate functions registered by defaults.init() method.
 	// In scheduler this method is run from app.runCommand().
 	// We also need to call it in CA to have simulation behaviour consistent with scheduler.
 	// Note: the logic of method is conditional and depends on feature gates enabled. To have same
 	//       behaviour in CA and scheduler both need to be run with same set of feature gates.
 	algorithmprovider.ApplyFeatureGates()
+	staticInitDone = true
 }
 
 // NoOpEventRecorder is a noop implementation of EventRecorder
@@ -92,6 +108,8 @@ func (NoOpEventRecorder) AnnotatedEventf(object runtime.Object, annotations map[
 
 // NewPredicateChecker builds PredicateChecker.
 func NewPredicateChecker(kubeClient kube_client.Interface, stop <-chan struct{}) (*PredicateChecker, error) {
+	staticInitIfNeeded()
+
 	informerFactory := informers.NewSharedInformerFactory(kubeClient, 0)
 	algorithmProvider := factory.DefaultProvider