added flags for ifconfig interface in server startup

cmd/server/main.go

@@ -1,6 +1,10 @@
 package main
 
 import (
+    "flag"
+    "log"
+    "os"
+    "fmt"
     "FRMS/internal/pkg/server"
 )
 
@@ -10,19 +14,32 @@ type reactorListener interface {
     GetPort() int
 }
 
-func NewReactorListener(ch chan error) reactorListener {
-    return server.NewReactorListener(ch)
+func NewReactorListener(s string,ch chan error) (reactorListener, error) {
+    return server.NewReactorListener(s, ch)
 }
 
 func main() {
     // lets get this bread
     // all we need to do is call the reactor coordinator and thats it
+    flag.Usage = func() {
+        w := flag.CommandLine.Output()
+        fmt.Fprintf(w,"Usage: %s [eth*,wlan*,etc.]\n",os.Args[0])
+    }
+    flag.Parse()
+    if flag.NArg() != 1 {
+        flag.Usage()
+        log.Fatal("Specify ifconfig interface. See man ifconfig for further information")
+    }
+    ifconfig := string(flag.Arg(0))
     ch := make(chan error)
-    rl := NewReactorListener(ch)
+    rl, err := NewReactorListener(ifconfig,ch)
+    if err != nil {
+        log.Fatal(err)
+    }
     go rl.Start()
-    err := <-ch // blocking to wait for any errors and keep alive otherwise
+    err = <-ch // blocking to wait for any errors and keep alive otherwise
     if err != nil {
         //fmt.Printf("ERROR: %v\n",err)
-        return
+        log.Fatal(err)
     }
 }

internal/pkg/server/centralcoordinator.go

@@ -29,9 +29,19 @@ func GetPort() (int, error) {
     return system.GetPort()
 }
 
-func NewReactorListener(ch chan error) *ReactorListener {
+func NewReactorListener(ifconfig string,ch chan error) (*ReactorListener, error) {
     m := make(map[uint32]*ReactorManager)
-    return &ReactorListener{Err:ch, Reactor:m}
+    var ip string
+    var port int
+    var err error
+    if ip, err = GetIp(ifconfig); err != nil {
+        return &ReactorListener{}, err
+    }
+
+    if port, err = GetPort(); err != nil {
+        return &ReactorListener{}, err
+    }
+    return &ReactorListener{Ip:ip,Port:port,Err:ch, Reactor:m}, nil
 }
 
 func (r *ReactorListener) GetIp() string {
@@ -48,18 +58,6 @@ func (r *ReactorListener) GetPort() int {
 
 func (r *ReactorListener) Start() {
     // start grpc server and implement reciever
-    if ip, err := GetIp("eth2"); err != nil {
-        r.Err <-err
-    } else {
-        r.Ip = ip
-    }
-
-    if port, err := GetPort(); err != nil {
-        r.Err <-err
-    } else {
-        r.Port = port
-    }
-
     if err := r.Register(); err != nil {
         r.Err <- err
     }