kube-scheduler: output flags in logical sections

Kubernetes-commit: a77652e9ab25382706e98e24f6026e28a9fbe621

pkg/util/globalflag/globalflags.go

@@ -0,0 +1,74 @@
+/*
+Copyright 2018 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 globalflag
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/spf13/pflag"
+
+	"k8s.io/apiserver/pkg/util/logs"
+)
+
+// AddGlobalFlags explicitly registers flags that libraries (klog, verflag, etc.) register
+// against the global flagsets from "flag" and "github.com/spf13/pflag".
+// We do this in order to prevent unwanted flags from leaking into the component's flagset.
+func AddGlobalFlags(fs *pflag.FlagSet, name string) {
+	addGlogFlags(fs)
+	logs.AddFlags(fs)
+
+	fs.BoolP("help", "h", false, fmt.Sprintf("help for %s", name))
+}
+
+// addGlogFlags explicitly registers flags that klog libraries(k8s.io/klog) register.
+func addGlogFlags(fs *pflag.FlagSet) {
+	// lookup flags in global flag set and re-register the values with our flagset
+	global := flag.CommandLine
+	local := pflag.NewFlagSet(os.Args[0], pflag.ExitOnError)
+
+	register(global, local, "logtostderr")
+	register(global, local, "alsologtostderr")
+	register(global, local, "v")
+	register(global, local, "skip_headers")
+	register(global, local, "stderrthreshold")
+	register(global, local, "vmodule")
+	register(global, local, "log_backtrace_at")
+	register(global, local, "log_dir")
+	register(global, local, "log_file")
+
+	fs.AddFlagSet(local)
+}
+
+// normalize replaces underscores with hyphens
+// we should always use hyphens instead of underscores when registering component flags
+func normalize(s string) string {
+	return strings.Replace(s, "_", "-", -1)
+}
+
+// register adds a flag to local that targets the Value associated with the Flag named globalName in global
+func register(global *flag.FlagSet, local *pflag.FlagSet, globalName string) {
+	if f := global.Lookup(globalName); f != nil {
+		pflagFlag := pflag.PFlagFromGoFlag(f)
+		pflagFlag.Name = normalize(pflagFlag.Name)
+		local.AddFlag(pflagFlag)
+	} else {
+		panic(fmt.Sprintf("failed to find flag in global flagset (flag): %s", globalName))
+	}
+}

pkg/util/globalflag/globalflags_test.go

@@ -0,0 +1,86 @@
+/*
+Copyright 2018 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 globalflag
+
+import (
+	"flag"
+	"reflect"
+	"sort"
+	"strings"
+	"testing"
+
+	"github.com/spf13/pflag"
+
+	apiserverflag "k8s.io/apiserver/pkg/util/flag"
+)
+
+func TestAddGlobalFlags(t *testing.T) {
+	namedFlagSets := &apiserverflag.NamedFlagSets{}
+	nfs := namedFlagSets.FlagSet("global")
+	AddGlobalFlags(nfs, "test-cmd")
+
+	actualFlag := []string{}
+	nfs.VisitAll(func(flag *pflag.Flag) {
+		actualFlag = append(actualFlag, flag.Name)
+	})
+
+	// Get all flags from flags.CommandLine, except flag `test.*`.
+	wantedFlag := []string{"help"}
+	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
+	pflag.VisitAll(func(flag *pflag.Flag) {
+		if !strings.Contains(flag.Name, "test.") {
+			wantedFlag = append(wantedFlag, normalize(flag.Name))
+		}
+	})
+	sort.Strings(wantedFlag)
+
+	if !reflect.DeepEqual(wantedFlag, actualFlag) {
+		t.Errorf("[Default]: expected %+v, got %+v", wantedFlag, actualFlag)
+	}
+
+	tests := []struct {
+		expectedFlag  []string
+		matchExpected bool
+	}{
+		{
+			// Happy case
+			expectedFlag:  []string{"alsologtostderr", "help", "log-backtrace-at", "log-dir", "log-file", "log-flush-frequency", "logtostderr", "skip-headers", "stderrthreshold", "v", "vmodule"},
+			matchExpected: false,
+		},
+		{
+			// Missing flag
+			expectedFlag:  []string{"logtostderr", "log-dir"},
+			matchExpected: true,
+		},
+		{
+			// Empty flag
+			expectedFlag:  []string{},
+			matchExpected: true,
+		},
+		{
+			// Invalid flag
+			expectedFlag:  []string{"foo"},
+			matchExpected: true,
+		},
+	}
+
+	for i, test := range tests {
+		if reflect.DeepEqual(test.expectedFlag, actualFlag) == test.matchExpected {
+			t.Errorf("[%d]: expected %+v, got %+v", i, test.expectedFlag, actualFlag)
+		}
+	}
+}