Move configuration work to library

Signed-off-by: jcsiadal <jeremy.c.siadal@intel.com>

Update to support show correctly

Signed-off-by: jcsiadal <jeremy.c.siadal@intel.com>

internal/pkg/configure/nfs.go

@@ -0,0 +1,69 @@
+package configure
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/hpcng/warewulf/internal/pkg/util"
+	"github.com/hpcng/warewulf/internal/pkg/warewulfconf"
+	"github.com/hpcng/warewulf/internal/pkg/wwlog"
+	"github.com/pkg/errors"
+)
+
+func configureNFS(show bool) error {
+
+	controller, err := warewulfconf.New()
+	if err != nil {
+		wwlog.Printf(wwlog.ERROR, "%s\n", err)
+		os.Exit(1)
+	}
+
+	if controller.Network == "" {
+		wwlog.Printf(wwlog.ERROR, "Network must be defined in warewulf.conf to configure NFS\n")
+		os.Exit(1)
+	}
+	if controller.Netmask == "" {
+		wwlog.Printf(wwlog.ERROR, "Netmask must be defined in warewulf.conf to configure NFS\n")
+		os.Exit(1)
+	}
+
+	if !show {
+
+		if controller.Nfs.Enabled {
+			exports, err := os.OpenFile("/etc/exports", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
+			if err != nil {
+				wwlog.Printf(wwlog.ERROR, "%s\n", err)
+				os.Exit(1)
+			}
+			defer exports.Close()
+
+			fmt.Fprintf(exports, "# This file was written by Warewulf (wwctl configure nfs)\n")
+
+			for _, export := range controller.Nfs.ExportsExtended {
+				fmt.Fprintf(exports, "%s %s/%s(%s)\n", export.Path, controller.Network, controller.Netmask, export.ExportOptions)
+			}
+
+			fmt.Printf("Enabling and restarting the NFS services\n")
+			if controller.Nfs.SystemdName == "" {
+				err := util.SystemdStart("nfs-server")
+				if err != nil {
+					return errors.Wrap(err, "failed to start nfs-server")
+				}
+			} else {
+				err := util.SystemdStart(controller.Nfs.SystemdName)
+				if err != nil {
+					return errors.Wrap(err, "failed to start")
+				}
+			}
+		}
+	} else {
+		fmt.Printf("/etc/exports:\n")
+
+		for _, export := range controller.Nfs.ExportsExtended {
+			fmt.Printf("%s %s/%s\n", export.Path, controller.Network, controller.Netmask)
+		}
+		fmt.Printf("\n")
+	}
+
+	return nil
+}