Merge pull request #950 from thockin/hostname_domainname

Extract hostname from (hostname.domainname)

Author: aboch

etchosts/etchosts.go

@@ -8,6 +8,7 @@ import (
 	"io/ioutil"
 	"os"
 	"regexp"
+	"strings"
 	"sync"
 )
 
@@ -78,10 +79,17 @@ func Build(path, IP, hostname, domainname string, extraContent []Record) error {
 		//set main record
 		var mainRec Record
 		mainRec.IP = IP
+		// User might have provided a FQDN in hostname or split it across hostname
+		// and domainname.  We want the FQDN and the bare hostname.
+		fqdn := hostname
 		if domainname != "" {
-			mainRec.Hosts = fmt.Sprintf("%s.%s %s", hostname, domainname, hostname)
+			fqdn = fmt.Sprintf("%s.%s", fqdn, domainname)
+		}
+		parts := strings.SplitN(fqdn, ".", 2)
+		if len(parts) == 2 {
+			mainRec.Hosts = fmt.Sprintf("%s %s", fqdn, parts[0])
 		} else {
-			mainRec.Hosts = hostname
+			mainRec.Hosts = fqdn
 		}
 		if _, err := mainRec.WriteTo(content); err != nil {
 			return err

etchosts/etchosts_test.go

@@ -81,6 +81,28 @@ func TestBuildHostname(t *testing.T) {
 	}
 }
 
+func TestBuildHostnameFQDN(t *testing.T) {
+	file, err := ioutil.TempFile("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(file.Name())
+
+	err = Build(file.Name(), "10.11.12.13", "testhostname.testdomainname.com", "", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	content, err := ioutil.ReadFile(file.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if expected := "10.11.12.13\ttesthostname.testdomainname.com testhostname\n"; !bytes.Contains(content, []byte(expected)) {
+		t.Fatalf("Expected to find '%s' got '%s'", expected, content)
+	}
+}
+
 func TestBuildNoIP(t *testing.T) {
 	file, err := ioutil.TempFile("", "")
 	if err != nil {