Better handling of when the specified port is already in use

diff --git a/commands/server.go b/commands/server.go
index ed04f04103d559b81fad9b1c3ed4f4c91e04b1bb..2b2794fe8ec60c7c2ac133fc8667357ef921c9e7 100644 (file)
--- a/commands/server.go
+++ b/commands/server.go
@@ -15,6 +15,7 @@ package commands
 
 import (
        "fmt"
+       "net"
        "net/http"
        "os"
        "strconv"
@@ -56,6 +57,19 @@ func server(cmd *cobra.Command, args []string) {
                BaseUrl = "http://" + BaseUrl
        }
 
+       l, err := net.Listen("tcp", ":"+strconv.Itoa(serverPort))
+       if err == nil {
+               l.Close()
+       } else {
+               jww.ERROR.Println("port", serverPort, "already in use, attempting to use an available port")
+               sp, err := helpers.FindAvailablePort()
+               if err != nil {
+                       jww.ERROR.Println("Unable to find alternative port to use")
+                       jww.ERROR.Fatalln(err)
+               }
+               serverPort = sp.Port
+       }
+
        if serverAppend {
                viper.Set("BaseUrl", strings.TrimSuffix(BaseUrl, "/")+":"+strconv.Itoa(serverPort))
        } else {

diff --git a/helpers/general.go b/helpers/general.go
index 208b0d2d3187408c49ae54cbd93105eaef1766e8..a2ebac9e1ca6931055c84e8907480534cd8aedd4 100644 (file)
--- a/helpers/general.go
+++ b/helpers/general.go
@@ -15,6 +15,8 @@ package helpers
 
 import (
        "bytes"
+       "fmt"
+       "net"
        "strings"
 )
 
@@ -49,3 +51,16 @@ func StripHTML(s string) string {
        }
        return output
 }
+
+func FindAvailablePort() (*net.TCPAddr, error) {
+       l, err := net.Listen("tcp", ":0")
+       if err == nil {
+               defer l.Close()
+               addr := l.Addr()
+               if a, ok := addr.(*net.TCPAddr); ok {
+                       return a, nil
+               }
+               return nil, fmt.Errorf("Unable to obtain a valid tcp port. %v", addr)
+       }
+       return nil, err
+}