Add util.PortRange, so that a port range can be a flag. Format: lo-hi

pkg/util/port_range.go

@@ -0,0 +1,100 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+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 util
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// PortRange represents a range of TCP/UDP ports.  To represent a single port,
+// set Size to 1.
+type PortRange struct {
+	Base int
+	Size int
+}
+
+// Contains tests whether a given port falls within the PortRange.
+func (pr *PortRange) Contains(p int) bool {
+	return (p >= pr.Base) && ((p - pr.Base) < pr.Size)
+}
+
+// String converts the PortRange to a string representation, which can be
+// parsed by PortRange.Set or ParsePortRange.
+func (pr PortRange) String() string {
+	if pr.Size == 0 {
+		return ""
+	}
+	return fmt.Sprintf("%d-%d", pr.Base, pr.Base+pr.Size-1)
+}
+
+// Set parses a string of the form "min-max", inclusive at both ends, and
+// sets the PortRange from it.  This is part of the flag.Value and pflag.Value
+// interfaces.
+func (pr *PortRange) Set(value string) error {
+	value = strings.TrimSpace(value)
+
+	// TODO: Accept "80" syntax
+	// TODO: Accept "80+8" syntax
+
+	if value == "" {
+		pr.Base = 0
+		pr.Size = 0
+		return nil
+	}
+
+	hyphenIndex := strings.Index(value, "-")
+	if hyphenIndex == -1 {
+		return fmt.Errorf("expected hyphen in port range")
+	}
+
+	var err error
+	var low int
+	var high int
+	low, err = strconv.Atoi(value[:hyphenIndex])
+	if err == nil {
+		high, err = strconv.Atoi(value[hyphenIndex+1:])
+	}
+	if err != nil {
+		return fmt.Errorf("unable to parse port range: %s", value)
+	}
+
+	if high < low {
+		return fmt.Errorf("end port cannot be less than start port: %s", value)
+	}
+	pr.Base = low
+	pr.Size = 1 + high - low
+	return nil
+}
+
+// Type returns a descriptive string about this type.  This is part of the
+// pflag.Value interface.
+func (*PortRange) Type() string {
+	return "portRange"
+}
+
+// ParsePortRange parses a string of the form "min-max", inclusive at both
+// ends, and initializs a new PortRange from it.
+func ParsePortRange(value string) (*PortRange, error) {
+	pr := &PortRange{}
+	err := pr.Set(value)
+	if err != nil {
+		return nil, err
+	}
+	return pr, nil
+}

pkg/util/port_range_test.go

@@ -0,0 +1,66 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+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 util
+
+import (
+	"testing"
+
+	flag "github.com/spf13/pflag"
+)
+
+func TestPortRange(t *testing.T) {
+	testCases := []struct {
+		input    string
+		success  bool
+		expected string
+		included int
+		excluded int
+	}{
+		{"100-200", true, "100-200", 200, 201},
+		{" 100-200 ", true, "100-200", 200, 201},
+		{"0-0", true, "0-0", 0, 1},
+		{"", true, "", -1, 0},
+		{"100", false, "", -1, -1},
+		{"100 - 200", false, "", -1, -1},
+		{"-100", false, "", -1, -1},
+		{"100-", false, "", -1, -1},
+	}
+
+	for i := range testCases {
+		tc := &testCases[i]
+		pr := &PortRange{}
+		var f flag.Value = pr
+		err := f.Set(tc.input)
+		if err != nil && tc.success == true {
+			t.Errorf("expected success, got %q", err)
+			continue
+		} else if err == nil && tc.success == false {
+			t.Errorf("expected failure")
+			continue
+		} else if tc.success {
+			if f.String() != tc.expected {
+				t.Errorf("expected %q, got %q", tc.expected, f.String())
+			}
+			if tc.included >= 0 && !pr.Contains(tc.included) {
+				t.Errorf("expected %q to include %d", f.String(), tc.included)
+			}
+			if tc.excluded >= 0 && pr.Contains(tc.excluded) {
+				t.Errorf("expected %q to exclude %d", f.String(), tc.excluded)
+			}
+		}
+	}
+}