[feat] listen on available port

1 files changed, 49 insertions, 0 deletions

diff --git a/pkg/helper/ports.go b/pkg/helper/ports.go
new file mode 100644
index 0000000..58e5856
--- /dev/null
+++ b/pkg/helper/ports.go
@@ -0,0 +1,49 @@
+package helper
+
+import (
+	"io/ioutil"
+	"net"
+	"os"
+	"path"
+	"strconv"
+)
+
+func getFirstAvailablePortFrom(port int) int {
+	for {
+		if isPortAvailable(port) {
+			return port
+		}
+		if port > 65535 {
+			return 0
+		}
+		port += 1
+	}
+}
+
+func isPortAvailable(port int) bool {
+	conn, err := net.Dial("tcp", "127.0.0.1:"+strconv.Itoa(port))
+	if err != nil {
+		return true
+	} else {
+		defer conn.Close()
+		return false
+	}
+}
+
+func writePortToFile(port int) error {
+	exeDir, err := getExecutableDir()
+	if err != nil {
+		return err
+	}
+	portFile := path.Join(exeDir, "port")
+	return ioutil.WriteFile(portFile, []byte(strconv.Itoa(port)+"\n"), 0644)
+
+}
+
+func getExecutableDir() (string, error) {
+	ex, err := os.Executable()
+	if err != nil {
+		return "", err
+	}
+	return path.Dir(ex), nil
+}