Decouple shared functions between controllers (#8829)

* Decouple shared functions between controllers

* Apply suggestions from code review

Co-authored-by: Jintao Zhang <tao12345666333@163.com>

* Fix package names and fmt

Co-authored-by: Jintao Zhang <tao12345666333@163.com>

pkg/flags/flags_test.go

@@ -0,0 +1,110 @@
+/*
+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 flags
+
+import (
+	"os"
+	"testing"
+)
+
+func TestNoMandatoryFlag(t *testing.T) {
+	_, _, err := ParseFlags()
+	if err != nil {
+		t.Fatalf("Expected no error but got: %s", err)
+	}
+}
+
+func TestDefaults(t *testing.T) {
+	ResetForTesting(func() { t.Fatal("Parsing failed") })
+
+	oldArgs := os.Args
+	defer func() { os.Args = oldArgs }()
+	os.Args = []string{"cmd",
+		"--default-backend-service", "namespace/test",
+		"--http-port", "0",
+		"--https-port", "0",
+	}
+
+	showVersion, conf, err := ParseFlags()
+	if err != nil {
+		t.Fatalf("Unexpected error parsing default flags: %v", err)
+	}
+
+	if showVersion {
+		t.Fatal("Expected flag \"show-version\" to be false")
+	}
+
+	if conf == nil {
+		t.Fatal("Expected a controller Configuration")
+	}
+}
+
+func TestSetupSSLProxy(t *testing.T) {
+	// TODO
+}
+
+func TestFlagConflict(t *testing.T) {
+	ResetForTesting(func() { t.Fatal("Parsing failed") })
+
+	oldArgs := os.Args
+	defer func() { os.Args = oldArgs }()
+	os.Args = []string{"cmd", "--publish-service", "namespace/test", "--http-port", "0", "--https-port", "0", "--publish-status-address", "1.1.1.1"}
+
+	_, _, err := ParseFlags()
+	if err == nil {
+		t.Fatalf("Expected an error parsing flags but none returned")
+	}
+}
+
+func TestMaxmindEdition(t *testing.T) {
+	ResetForTesting(func() { t.Fatal("Parsing failed") })
+
+	oldArgs := os.Args
+	defer func() { os.Args = oldArgs }()
+	os.Args = []string{"cmd", "--publish-service", "namespace/test", "--http-port", "0", "--https-port", "0", "--maxmind-license-key", "0000000", "--maxmind-edition-ids", "GeoLite2-City, TestCheck"}
+
+	_, _, err := ParseFlags()
+	if err == nil {
+		t.Fatalf("Expected an error parsing flags but none returned")
+	}
+}
+
+func TestMaxmindMirror(t *testing.T) {
+	ResetForTesting(func() { t.Fatal("Parsing failed") })
+
+	oldArgs := os.Args
+	defer func() { os.Args = oldArgs }()
+	os.Args = []string{"cmd", "--publish-service", "namespace/test", "--http-port", "0", "--https-port", "0", "--maxmind-mirror", "http://geoip.local", "--maxmind-license-key", "0000000", "--maxmind-edition-ids", "GeoLite2-City, TestCheck"}
+
+	_, _, err := ParseFlags()
+	if err == nil {
+		t.Fatalf("Expected an error parsing flags but none returned")
+	}
+}
+
+func TestMaxmindRetryDownload(t *testing.T) {
+	ResetForTesting(func() { t.Fatal("Parsing failed") })
+
+	oldArgs := os.Args
+	defer func() { os.Args = oldArgs }()
+	os.Args = []string{"cmd", "--publish-service", "namespace/test", "--http-port", "0", "--https-port", "0", "--maxmind-mirror", "http://127.0.0.1", "--maxmind-license-key", "0000000", "--maxmind-edition-ids", "GeoLite2-City", "--maxmind-retries-timeout", "1s", "--maxmind-retries-count", "3"}
+
+	_, _, err := ParseFlags()
+	if err == nil {
+		t.Fatalf("Expected an error parsing flags but none returned")
+	}
+}