Create & Init Project...

app/service/main/bns/lib/BUILD

@@ -0,0 +1,25 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_test",
+    "go_library",
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [
+        ":package-srcs",
+        "//app/service/main/bns/lib/resolvconf:all-srcs",
+        "//app/service/main/bns/lib/shuffle:all-srcs",
+    ],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

app/service/main/bns/lib/resolvconf/BUILD

@@ -0,0 +1,37 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_test",
+    "go_library",
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["resolvconf_unix_test.go"],
+    embed = [":go_default_library"],
+    rundir = ".",
+    tags = ["automanaged"],
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["resolvconf_unix.go"],
+    importpath = "go-common/app/service/main/bns/lib/resolvconf",
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

app/service/main/bns/lib/resolvconf/resolvconf_unix.go

@@ -0,0 +1,56 @@
+// +build linux darwin
+
+package resolvconf
+
+import (
+	"bufio"
+	"io"
+	"os"
+	"strings"
+)
+
+const (
+	resolvConfPath = "/etc/resolv.conf"
+)
+
+// ParseResolvConf parse /etc/resolv.conf file and return nameservers
+func ParseResolvConf() ([]string, error) {
+	fp, err := os.Open(resolvConfPath)
+	if err != nil {
+		return nil, err
+	}
+	defer fp.Close()
+	return parse(fp)
+}
+
+func parse(fp io.Reader) ([]string, error) {
+	var result []string
+
+	bufRd := bufio.NewReader(fp)
+	for {
+		line, err := bufRd.ReadString('\n')
+		if err != nil {
+			if err != io.EOF {
+				return nil, err
+			}
+			if line == "" {
+				break
+			}
+		}
+		line = strings.TrimSpace(line)
+
+		// ignore comment, comment startwith #
+		if strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		fields := strings.Fields(line)
+		if len(fields) < 2 {
+			continue
+		}
+		if fields[0] == "nameserver" {
+			result = append(result, fields[1:]...)
+		}
+	}
+	return result, nil
+}

app/service/main/bns/lib/resolvconf/resolvconf_unix_test.go

@@ -0,0 +1,72 @@
+// +build linux darwin
+
+package resolvconf
+
+import (
+	"bytes"
+	"io"
+	"reflect"
+	"testing"
+)
+
+const (
+	testdata1 = `domain localdomain
+search localdomain
+nameserver 192.168.6.2`
+	testdata2 = `#
+# macOS Notice
+#
+# This file is not consulted for DNS hostname resolution, address
+# resolution, or the DNS query routing mechanism used by most
+# processes on this system.
+#
+# To view the DNS configuration used by this system, use:
+#   scutil --dns
+#
+# SEE ALSO
+#   dns-sd(1), scutil(8)
+#
+# This file is automatically generated.
+#
+nameserver 10.23.194.202
+nameserver 10.23.194.203`
+)
+
+func Test_parse(t *testing.T) {
+	type args struct {
+		fp io.Reader
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    []string
+		wantErr bool
+	}{
+		{
+			name: "test1",
+			args: args{
+				bytes.NewBufferString(testdata1),
+			},
+			want: []string{"192.168.6.2"},
+		},
+		{
+			name: "test2",
+			args: args{
+				bytes.NewBufferString(testdata2),
+			},
+			want: []string{"10.23.194.202", "10.23.194.203"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := parse(tt.args.fp)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("parse() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("parse() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

app/service/main/bns/lib/resolvconf/resolvconf_windows.go

@@ -0,0 +1,8 @@
+// +build windows
+
+package resolvconf
+
+// ParseResolvConf TODO: windows support
+func ParseResolvConf() ([]string, error) {
+	return []string{}, nil
+}

app/service/main/bns/lib/shuffle/BUILD

@@ -0,0 +1,37 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_test",
+    "go_library",
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["shuffle_test.go"],
+    embed = [":go_default_library"],
+    rundir = ".",
+    tags = ["automanaged"],
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["shuffle.go"],
+    importpath = "go-common/app/service/main/bns/lib/shuffle",
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

app/service/main/bns/lib/shuffle/shuffle.go

@@ -0,0 +1,26 @@
+package shuffle
+
+import (
+	"math/rand"
+	"time"
+)
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+// Shuffler A type, typically a collection, that satisfies Shuffler
+// can be shuffle by Shuffle func
+type Shuffler interface {
+	Len() int
+	Swap(i, j int)
+}
+
+// Shuffle s
+func Shuffle(s Shuffler) {
+	l := s.Len()
+	for i := l; i > 0; i-- {
+		j := rand.Intn(i)
+		s.Swap(l-i, j)
+	}
+}

app/service/main/bns/lib/shuffle/shuffle_test.go

@@ -0,0 +1,27 @@
+package shuffle
+
+import (
+	"strings"
+	"testing"
+)
+
+type List []string
+
+func (l List) Len() int {
+	return len(l)
+}
+
+func (l List) Swap(i, j int) {
+	l[i], l[j] = l[j], l[i]
+}
+
+func TestShuffle(t *testing.T) {
+	l := List{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"}
+	old := strings.Join(l, "")
+	Shuffle(l)
+	new := strings.Join(l, "")
+	if old == new {
+		t.Errorf("shuffle error, %s == %s", old, new)
+	}
+	t.Log(new)
+}