implement ip generator for nodes

Signed-off-by: Chanwit Kaewkasi <chanwit@gmail.com>

discovery/generator.go

@@ -0,0 +1,37 @@
+package discovery
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+)
+
+//
+// IP generator
+//
+func Generate(pattern string) []string {
+	re, _ := regexp.Compile(`\[(.+):(.+)\]`)
+	submatch := re.FindStringSubmatch(pattern)
+	if submatch == nil {
+		return []string{pattern}
+	}
+
+	from, err := strconv.Atoi(submatch[1])
+	if err != nil {
+		return []string{pattern}
+	}
+	to, err := strconv.Atoi(submatch[2])
+	if err != nil {
+		return []string{pattern}
+	}
+
+	template := re.ReplaceAllString(pattern, "%d")
+
+	result := make([]string, 0)
+	for val := from; val <= to; val++ {
+		entry := fmt.Sprintf(template, val)
+		result = append(result, entry)
+	}
+
+	return result
+}

discovery/generator_test.go

@@ -0,0 +1,41 @@
+package discovery
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGeneratorNotGenerate(t *testing.T) {
+	ips := Generate("127.0.0.1")
+	assert.Equal(t, len(ips), 1)
+	assert.Equal(t, ips[0], "127.0.0.1")
+}
+
+func TestGeneratorWithPortNotGenerate(t *testing.T) {
+	ips := Generate("127.0.0.1:8080")
+	assert.Equal(t, len(ips), 1)
+	assert.Equal(t, ips[0], "127.0.0.1:8080")
+}
+
+func TestGeneratorMatchFailedNotGenerate(t *testing.T) {
+	ips := Generate("127.0.0.[1]")
+	assert.Equal(t, len(ips), 1)
+	assert.Equal(t, ips[0], "127.0.0.[1]")
+}
+
+func TestGeneratorWithPort(t *testing.T) {
+	ips := Generate("127.0.0.[1:11]:2375")
+	assert.Equal(t, len(ips), 11)
+	assert.Equal(t, ips[0], "127.0.0.1:2375")
+	assert.Equal(t, ips[1], "127.0.0.2:2375")
+	assert.Equal(t, ips[2], "127.0.0.3:2375")
+	assert.Equal(t, ips[3], "127.0.0.4:2375")
+	assert.Equal(t, ips[4], "127.0.0.5:2375")
+	assert.Equal(t, ips[5], "127.0.0.6:2375")
+	assert.Equal(t, ips[6], "127.0.0.7:2375")
+	assert.Equal(t, ips[7], "127.0.0.8:2375")
+	assert.Equal(t, ips[8], "127.0.0.9:2375")
+	assert.Equal(t, ips[9], "127.0.0.10:2375")
+	assert.Equal(t, ips[10], "127.0.0.11:2375")
+}

discovery/nodes/nodes.go

@@ -15,12 +15,14 @@ func init() {
 }
 
 func (s *NodesDiscoveryService) Initialize(uris string, _ int) error {
-	for _, ip := range strings.Split(uris, ",") {
-		entry, err := discovery.NewEntry(ip)
-		if err != nil {
-			return err
+	for _, input := range strings.Split(uris, ",") {
+		for _, ip := range discovery.Generate(input) {
+			entry, err := discovery.NewEntry(ip)
+			if err != nil {
+				return err
+			}
+			s.entries = append(s.entries, entry)
 		}
-		s.entries = append(s.entries, entry)
 	}
 
 	return nil

discovery/nodes/nodes_test.go

@@ -14,6 +14,17 @@ func TestInitialise(t *testing.T) {
 	assert.Equal(t, discovery.entries[1].String(), "2.2.2.2:2222")
 }
 
+func TestInitialiseWithPattern(t *testing.T) {
+	discovery := &NodesDiscoveryService{}
+	discovery.Initialize("1.1.1.[1:2]:1111,2.2.2.[2:4]:2222", 0)
+	assert.Equal(t, len(discovery.entries), 5)
+	assert.Equal(t, discovery.entries[0].String(), "1.1.1.1:1111")
+	assert.Equal(t, discovery.entries[1].String(), "1.1.1.2:1111")
+	assert.Equal(t, discovery.entries[2].String(), "2.2.2.2:2222")
+	assert.Equal(t, discovery.entries[3].String(), "2.2.2.3:2222")
+	assert.Equal(t, discovery.entries[4].String(), "2.2.2.4:2222")
+}
+
 func TestRegister(t *testing.T) {
 	discovery := &NodesDiscoveryService{}
 	assert.Error(t, discovery.Register("0.0.0.0"))