fix that hostname is added multiple times

cmd/hostname_set.go

@@ -71,25 +71,10 @@ func set_hostname(args ...string) {
 			panic(err)
 		}
 
-		input, err := ioutil.ReadFile("/etc/hosts")
-		if err != nil {
-			panic(err)
-		}
-
-		lines := strings.Split(string(input), "\n")
-		lines_new := []string{}
+		hostname_line := fmt.Sprintf("127.0.0.1	%s # added by device-init", hostname)
 
-		for i, line := range lines {
-			if strings.Contains(line, "127.0.0.1	localhost") {
-				lines_new = append(lines_new, lines[0:i+1]...)
-				lines_new = append(lines_new, fmt.Sprintf("127.0.0.1	%s", hostname))
-				lines_new = append(lines_new, lines[i+1:]...)
-			}
-		}
-		output := strings.Join(lines_new, "\n")
-		err = ioutil.WriteFile("/etc/hosts", []byte(output), 0644)
-		if err != nil {
-			panic(err)
+		if !is_present_in_hosts_file(hostname_line) && !is_present_in_hosts_file(hostname) {
+			addHostname(hostname_line)
 		}
 
 		err = exec.Command("hostname", hostname).Run()
@@ -140,3 +125,49 @@ func activeInterfaces() []string {
 	}
 	return result
 }
+
+func is_present_in_hosts_file(search_string string) bool {
+	found := false
+	for _, line := range readHostsFile() {
+		if strings.Contains(line, search_string) {
+			found = true
+		}
+	}
+	return found
+}
+
+func addHostname(hostname_line string) {
+	lines_old := readHostsFile()
+	lines_new := []string{}
+
+	if is_present_in_hosts_file("# added by device-init") {
+		for i, line := range lines_old {
+			if strings.Contains(line, "# added by device-init") {
+				lines_new = append(lines_new, lines_old[0:i]...)
+				lines_new = append(lines_new, hostname_line)
+				lines_new = append(lines_new, lines_old[i+1:]...)
+			}
+		}
+	} else {
+		for i, line := range lines_old {
+			if strings.Contains(line, "127.0.0.1	localhost") {
+				lines_new = append(lines_new, lines_old[0:i+1]...)
+				lines_new = append(lines_new, hostname_line)
+				lines_new = append(lines_new, lines_old[i+1:]...)
+			}
+		}
+	}
+	output := strings.Join(lines_new, "\n")
+	err := ioutil.WriteFile("/etc/hosts", []byte(output), 0644)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func readHostsFile() []string {
+	input, err := ioutil.ReadFile("/etc/hosts")
+	if err != nil {
+		panic(err)
+	}
+	return strings.Split(string(input), "\n")
+}

specs/device-init_spec.rb

@@ -18,7 +18,7 @@
 
   context "hostname" do
     before(:each) do
-      system('device-init hostname set device-tester >> /dev/null')
+      # system('device-init hostname set device-tester >> /dev/null')
       system('rm -f /boot/device-init.yaml')
     end
 
@@ -31,28 +31,67 @@
       end
 
       it "sets hostname" do
-        old_hostname_cmd_result = command('hostname').stdout
-        device_init_cmd_result = command('device-init hostname set black-pearl').stdout
+        device_init_cmd_result = command('device-init hostname set black-beauty').stdout
         new_hostname_cmd_result = command('hostname').stdout
 
-        expect(old_hostname_cmd_result).to contain("device-tester")
         expect(device_init_cmd_result).to contain("Set")
-        expect(new_hostname_cmd_result).to contain("black-pearl")
+        expect(new_hostname_cmd_result).to contain("black-beauty")
+      end
+
+      it "does not set hostname twice" do
+        device_init_cmd_result_one = command('device-init hostname set black-widow').stdout
+        device_init_cmd_result_two = command('device-init hostname set black-widow').stdout
+        hosts_file_content = command('cat /etc/hosts').stdout
+
+        expect(device_init_cmd_result_one).to contain("Set")
+        expect(device_init_cmd_result_two).to contain("Set")
+        expect(hosts_file_content.scan(/black-widow/).count).to eq(1)
+      end
+
+      it "replaces existing device-init hostname entry if it already exists" do
+        device_init_cmd_result = command('device-init hostname set black-mamba').stdout
+        hosts_file_content = command('cat /etc/hosts').stdout
+
+        expect(device_init_cmd_result).to contain("Set")
+        expect(hosts_file_content.scan(/black-mamba/).count).to eq(1)
+        expect(hosts_file_content.scan(/black-widow/).count).to eq(0)
+      end
+
+      it "it does not replaces existing hostname entry if it already exists" do
+        hostname = 'black-pearl'
+        hosts_file = %Q(
+127.0.0.1 localhost
+127.0.0.1 #{hostname}
+::1 localhost ip6-localhost ip6-loopback
+fe00::0 ip6-localnet
+ff00::0 ip6-mcastprefix
+ff02::1 ip6-allnodes
+ff02::2 ip6-allrouters
+172.17.0.2  device-tester
+        )
+
+        command(%Q(echo -n '#{hosts_file}' > /etc/hosts)).stdout
+        device_init_cmd_result = command("device-init hostname set #{hostname}").stdout
+        hosts_file_content = command('cat /etc/hosts').stdout
+
+        expect(device_init_cmd_result).to contain("Set")
+        expect(hosts_file_content.scan(/\# added by device-init/).count).to eq(0)
+        expect(hosts_file_content.scan(/#{Regexp.quote(hostname)}/).count).to eq(1)
       end
     end
 
     context "with config-file" do
       it "sets hostname" do
-        status = command(%q(echo -n 'hostname: "black-pearl"\n' > /boot/device-init.yaml)).exit_status
+        status = command(%q(echo -n 'hostname: "black-mood"\n' > /boot/device-init.yaml)).exit_status
         expect(status).to be(0)
 
         old_hostname_cmd_result = command('hostname').stdout
         device_init_cmd_result = command('device-init --config').stdout
         new_hostname_cmd_result = command('hostname').stdout
 
-        expect(old_hostname_cmd_result).to contain("device-tester")
+        expect(old_hostname_cmd_result).to contain("black-pearl")
         expect(device_init_cmd_result).to contain("Set")
-        expect(new_hostname_cmd_result).to contain("black-pearl")
+        expect(new_hostname_cmd_result).to contain("black-mood")
       end
     end
   end