Merge pull request #40696 from jayunit100/sched_server_cleanup

Automatic merge from submit-queue (batch tested with PRs 40696, 39914, 40374)

Cleanup scheduler server with an external config class

**What this PR does / why we need it**:

Some cleanup in cmd/server so that the parts which setup scheduler configuration are stored and separately tested. 

- additionally a simple unit test to check that erroneous configs return a non-nil error is included.
- it also will make sure we  avoid nil panics of schedulerConfiguration is misconfigured.

plugin/cmd/kube-scheduler/app/BUILD

@@ -5,11 +5,15 @@ licenses(["notice"])
 load(
     "@io_bazel_rules_go//go:def.bzl",
     "go_library",
+    "go_test",
 )
 
 go_library(
     name = "go_default_library",
-    srcs = ["server.go"],
+    srcs = [
+        "configurator.go",
+        "server.go",
+    ],
     tags = ["automanaged"],
     deps = [
         "//pkg/api:go_default_library",
@@ -53,3 +57,10 @@ filegroup(
     ],
     tags = ["automanaged"],
 )
+
+go_test(
+    name = "go_default_test",
+    srcs = ["configurator_test.go"],
+    library = ":go_default_library",
+    tags = ["automanaged"],
+)

plugin/cmd/kube-scheduler/app/configurator.go

@@ -0,0 +1,113 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package app
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"k8s.io/kubernetes/plugin/cmd/kube-scheduler/app/options"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	v1core "k8s.io/client-go/kubernetes/typed/core/v1"
+
+	restclient "k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/clientcmd"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/client/clientset_generated/clientset"
+
+	clientv1 "k8s.io/client-go/pkg/api/v1"
+
+	"k8s.io/kubernetes/plugin/pkg/scheduler"
+	_ "k8s.io/kubernetes/plugin/pkg/scheduler/algorithmprovider"
+	schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
+	latestschedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api/latest"
+	"k8s.io/kubernetes/plugin/pkg/scheduler/factory"
+
+	"github.com/golang/glog"
+)
+
+func createRecorder(kubecli *clientset.Clientset, s *options.SchedulerServer) record.EventRecorder {
+	eventBroadcaster := record.NewBroadcaster()
+	eventBroadcaster.StartLogging(glog.Infof)
+	eventBroadcaster.StartRecordingToSink(&v1core.EventSinkImpl{Interface: v1core.New(kubecli.Core().RESTClient()).Events("")})
+	return eventBroadcaster.NewRecorder(api.Scheme, clientv1.EventSource{Component: s.SchedulerName})
+}
+
+func createClient(s *options.SchedulerServer) (*clientset.Clientset, error) {
+	kubeconfig, err := clientcmd.BuildConfigFromFlags(s.Master, s.Kubeconfig)
+	if err != nil {
+		return nil, fmt.Errorf("unable to build config from flags: %v", err)
+	}
+
+	kubeconfig.ContentType = s.ContentType
+	// Override kubeconfig qps/burst settings from flags
+	kubeconfig.QPS = s.KubeAPIQPS
+	kubeconfig.Burst = int(s.KubeAPIBurst)
+
+	cli, err := clientset.NewForConfig(restclient.AddUserAgent(kubeconfig, "leader-election"))
+	if err != nil {
+		return nil, fmt.Errorf("invalid API configuration: %v", err)
+	}
+	return cli, nil
+}
+
+// createScheduler encapsulates the entire creation of a runnable scheduler.
+func createScheduler(s *options.SchedulerServer, kubecli *clientset.Clientset, recorder record.EventRecorder) (*scheduler.Scheduler, error) {
+	configurator := factory.NewConfigFactory(kubecli, s.SchedulerName, s.HardPodAffinitySymmetricWeight, s.FailureDomains)
+
+	// Rebuild the configurator with a default Create(...) method.
+	configurator = &schedulerConfigurator{
+		configurator,
+		s.PolicyConfigFile,
+		s.AlgorithmProvider}
+
+	return scheduler.NewFromConfigurator(configurator, func(cfg *scheduler.Config) {
+		cfg.Recorder = recorder
+	})
+}
+
+// schedulerConfigurator is an interface wrapper that provides default Configuration creation based on user
+// provided config file.
+type schedulerConfigurator struct {
+	scheduler.Configurator
+	policyFile        string
+	algorithmProvider string
+}
+
+// Create implements the interface for the Configurator, hence it is exported even through the struct is not.
+func (sc schedulerConfigurator) Create() (*scheduler.Config, error) {
+	if _, err := os.Stat(sc.policyFile); err != nil {
+		if sc.Configurator != nil {
+			return sc.Configurator.CreateFromProvider(sc.algorithmProvider)
+		}
+		return nil, fmt.Errorf("Configurator was nil")
+	}
+
+	// policy file is valid, try to create a configuration from it.
+	var policy schedulerapi.Policy
+	configData, err := ioutil.ReadFile(sc.policyFile)
+	if err != nil {
+		return nil, fmt.Errorf("unable to read policy config: %v", err)
+	}
+	if err := runtime.DecodeInto(latestschedulerapi.Codec, configData, &policy); err != nil {
+		return nil, fmt.Errorf("invalid configuration: %v", err)
+	}
+	return sc.CreateFromConfig(policy)
+}

plugin/cmd/kube-scheduler/app/configurator_test.go

@@ -0,0 +1,31 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package app
+
+import (
+	"testing"
+)
+
+func TestSchedulerConfiguratorFailure(t *testing.T) {
+	sc := &schedulerConfigurator{
+	// policyfile and algorithm are intentionally undefined.
+	}
+	_, error := sc.Create()
+	if error == nil {
+		t.Fatalf("Expected error message when creating with incomplete configurator.")
+	}
+}

plugin/cmd/kube-scheduler/app/server.go

@@ -19,7 +19,6 @@ package app
 
 import (
 	"fmt"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/http/pprof"
@@ -28,24 +27,13 @@ import (
 	"strconv"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apiserver/pkg/server/healthz"
-	v1core "k8s.io/client-go/kubernetes/typed/core/v1"
+
-	clientv1 "k8s.io/client-go/pkg/api/v1"
-	restclient "k8s.io/client-go/rest"
-	"k8s.io/client-go/tools/clientcmd"
-	"k8s.io/client-go/tools/record"
-	"k8s.io/kubernetes/pkg/api"
-	"k8s.io/kubernetes/pkg/client/clientset_generated/clientset"
 	"k8s.io/kubernetes/pkg/client/leaderelection"
 	"k8s.io/kubernetes/pkg/client/leaderelection/resourcelock"
 	"k8s.io/kubernetes/pkg/util/configz"
 	"k8s.io/kubernetes/plugin/cmd/kube-scheduler/app/options"
-	"k8s.io/kubernetes/plugin/pkg/scheduler"
 	_ "k8s.io/kubernetes/plugin/pkg/scheduler/algorithmprovider"
-	schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
-	latestschedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api/latest"
-	"k8s.io/kubernetes/plugin/pkg/scheduler/factory"
 
 	"github.com/golang/glog"
 	"github.com/prometheus/client_golang/prometheus"
@@ -124,13 +112,6 @@ func Run(s *options.SchedulerServer) error {
 	panic("unreachable")
 }
 
-func createRecorder(kubecli *clientset.Clientset, s *options.SchedulerServer) record.EventRecorder {
-	eventBroadcaster := record.NewBroadcaster()
-	eventBroadcaster.StartLogging(glog.Infof)
-	eventBroadcaster.StartRecordingToSink(&v1core.EventSinkImpl{Interface: v1core.New(kubecli.Core().RESTClient()).Events("")})
-	return eventBroadcaster.NewRecorder(api.Scheme, clientv1.EventSource{Component: s.SchedulerName})
-}
-
 func startHTTP(s *options.SchedulerServer) {
 	mux := http.NewServeMux()
 	healthz.InstallHandler(mux)
@@ -156,61 +137,3 @@ func startHTTP(s *options.SchedulerServer) {
 	}
 	glog.Fatal(server.ListenAndServe())
 }
-
-func createClient(s *options.SchedulerServer) (*clientset.Clientset, error) {
-	kubeconfig, err := clientcmd.BuildConfigFromFlags(s.Master, s.Kubeconfig)
-	if err != nil {
-		return nil, fmt.Errorf("unable to build config from flags: %v", err)
-	}
-
-	kubeconfig.ContentType = s.ContentType
-	// Override kubeconfig qps/burst settings from flags
-	kubeconfig.QPS = s.KubeAPIQPS
-	kubeconfig.Burst = int(s.KubeAPIBurst)
-
-	cli, err := clientset.NewForConfig(restclient.AddUserAgent(kubeconfig, "leader-election"))
-	if err != nil {
-		return nil, fmt.Errorf("invalid API configuration: %v", err)
-	}
-	return cli, nil
-}
-
-// schedulerConfigurator is an interface wrapper that provides default Configuration creation based on user
-// provided config file.
-type schedulerConfigurator struct {
-	scheduler.Configurator
-	policyFile        string
-	algorithmProvider string
-}
-
-func (sc schedulerConfigurator) Create() (*scheduler.Config, error) {
-	if _, err := os.Stat(sc.policyFile); err != nil {
-		return sc.Configurator.CreateFromProvider(sc.algorithmProvider)
-	}
-
-	// policy file is valid, try to create a configuration from it.
-	var policy schedulerapi.Policy
-	configData, err := ioutil.ReadFile(sc.policyFile)
-	if err != nil {
-		return nil, fmt.Errorf("unable to read policy config: %v", err)
-	}
-	if err := runtime.DecodeInto(latestschedulerapi.Codec, configData, &policy); err != nil {
-		return nil, fmt.Errorf("invalid configuration: %v", err)
-	}
-	return sc.CreateFromConfig(policy)
-}
-
-// createScheduler encapsulates the entire creation of a runnable scheduler.
-func createScheduler(s *options.SchedulerServer, kubecli *clientset.Clientset, recorder record.EventRecorder) (*scheduler.Scheduler, error) {
-	configurator := factory.NewConfigFactory(kubecli, s.SchedulerName, s.HardPodAffinitySymmetricWeight, s.FailureDomains)
-
-	// Rebuild the configurator with a default Create(...) method.
-	configurator = &schedulerConfigurator{
-		configurator,
-		s.PolicyConfigFile,
-		s.AlgorithmProvider}
-
-	return scheduler.NewFromConfigurator(configurator, func(cfg *scheduler.Config) {
-		cfg.Recorder = recorder
-	})
-}