refactor codes in volume iscsi to improve readability

pkg/volume/iscsi/iscsi_util.go

@@ -46,7 +46,9 @@ var (
 )
 
 func updateISCSIDiscoverydb(b iscsiDiskMounter, tp string) error {
-	if b.chap_discovery {
+	if !b.chap_discovery {
+		return nil
+	}
 	out, err := b.exec.Run("iscsiadm", "-m", "discoverydb", "-t", "sendtargets", "-p", tp, "-I", b.Iface, "-o", "update", "-n", "discovery.sendtargets.auth.authmethod", "-v", "CHAP")
 	if err != nil {
 		return fmt.Errorf("iscsi: failed to update discoverydb with CHAP, output: %v", string(out))
@@ -61,12 +63,14 @@ func updateISCSIDiscoverydb(b iscsiDiskMounter, tp string) error {
 			}
 		}
 	}
-	}
 	return nil
 }
 
 func updateISCSINode(b iscsiDiskMounter, tp string) error {
-	if b.chap_session {
+	if !b.chap_session {
+		return nil
+	}
+
 	out, err := b.exec.Run("iscsiadm", "-m", "node", "-p", tp, "-T", b.Iqn, "-I", b.Iface, "-o", "update", "-n", "node.session.auth.authmethod", "-v", "CHAP")
 	if err != nil {
 		return fmt.Errorf("iscsi: failed to update node with CHAP, output: %v", string(out))
@@ -81,7 +85,6 @@ func updateISCSINode(b iscsiDiskMounter, tp string) error {
 			}
 		}
 	}
-	}
 	return nil
 }
 
@@ -96,7 +99,10 @@ func waitForPathToExist(devicePath *string, maxRetries int, deviceTransport stri
 }
 
 func waitForPathToExistInternal(devicePath *string, maxRetries int, deviceTransport string, osStat StatFunc, filepathGlob GlobFunc) bool {
-	if devicePath != nil {
+	if devicePath == nil {
+		return false
+	}
+
 	for i := 0; i < maxRetries; i++ {
 		var err error
 		if deviceTransport == "tcp" {
@@ -123,7 +129,6 @@ func waitForPathToExistInternal(devicePath *string, maxRetries int, deviceTransp
 		}
 		time.Sleep(time.Second)
 	}
-	}
 	return false
 }
 
@@ -231,13 +236,18 @@ func (util *ISCSIUtil) AttachDisk(b iscsiDiskMounter) (string, error) {
 		if iscsiTransport == "" {
 			glog.Errorf("iscsi: could not find transport name in iface %s", b.Iface)
 			return "", fmt.Errorf("Could not parse iface file for %s", b.Iface)
-		} else if iscsiTransport == "tcp" {
+		}
+		if iscsiTransport == "tcp" {
 			devicePath = strings.Join([]string{"/dev/disk/by-path/ip", tp, "iscsi", b.Iqn, "lun", b.lun}, "-")
 		} else {
 			devicePath = strings.Join([]string{"/dev/disk/by-path/pci", "*", "ip", tp, "iscsi", b.Iqn, "lun", b.lun}, "-")
 		}
-		exist := waitForPathToExist(&devicePath, 1, iscsiTransport)
-		if exist == false {
+
+		if exist := waitForPathToExist(&devicePath, 1, iscsiTransport); exist {
+			glog.V(4).Infof("iscsi: devicepath (%s) exists", devicePath)
+			devicePaths = append(devicePaths, devicePath)
+			continue
+		}
 		// build discoverydb and discover iscsi target
 		b.exec.Run("iscsiadm", "-m", "discoverydb", "-t", "sendtargets", "-p", tp, "-I", b.Iface, "-o", "new")
 		// update discoverydb with CHAP secret
@@ -246,7 +256,7 @@ func (util *ISCSIUtil) AttachDisk(b iscsiDiskMounter) (string, error) {
 			lastErr = fmt.Errorf("iscsi: failed to update discoverydb to portal %s error: %v", tp, err)
 			continue
 		}
-			out, err := b.exec.Run("iscsiadm", "-m", "discoverydb", "-t", "sendtargets", "-p", tp, "-I", b.Iface, "--discover")
+		out, err = b.exec.Run("iscsiadm", "-m", "discoverydb", "-t", "sendtargets", "-p", tp, "-I", b.Iface, "--discover")
 		if err != nil {
 			// delete discoverydb record
 			b.exec.Run("iscsiadm", "-m", "discoverydb", "-t", "sendtargets", "-p", tp, "-I", b.Iface, "-o", "delete")
@@ -267,8 +277,7 @@ func (util *ISCSIUtil) AttachDisk(b iscsiDiskMounter) (string, error) {
 			lastErr = fmt.Errorf("iscsi: failed to attach disk: Error: %s (%v)", string(out), err)
 			continue
 		}
-			exist = waitForPathToExist(&devicePath, 10, iscsiTransport)
-			if !exist {
+		if exist := waitForPathToExist(&devicePath, 10, iscsiTransport); !exist {
 			glog.Errorf("Could not attach disk: Timeout after 10s")
 			// update last error
 			lastErr = fmt.Errorf("Could not attach disk: Timeout after 10s")
@@ -276,10 +285,6 @@ func (util *ISCSIUtil) AttachDisk(b iscsiDiskMounter) (string, error) {
 		} else {
 			devicePaths = append(devicePaths, devicePath)
 		}
-		} else {
-			glog.V(4).Infof("iscsi: devicepath (%s) exists", devicePath)
-			devicePaths = append(devicePaths, devicePath)
-		}
 	}
 
 	if len(devicePaths) == 0 {
@@ -348,14 +353,19 @@ func (util *ISCSIUtil) DetachDisk(c iscsiDiskUnmounter, mntPath string) error {
 		return err
 	}
 	cnt--
+	if cnt != 0 {
+		return nil
+	}
 	// if device is no longer used, see if need to logout the target
-	if cnt == 0 {
 	device, prefix, err := extractDeviceAndPrefix(mntPath)
 	if err != nil {
 		return err
 	}
 	refCount, err := getDevicePrefixRefCount(c.mounter, prefix)
-		if err == nil && refCount == 0 {
+	if err != nil || refCount != 0 {
+		return nil
+	}
+
 	var bkpPortal []string
 	var volName, iqn, iface, initiatorName string
 	found := true
@@ -384,20 +394,20 @@ func (util *ISCSIUtil) DetachDisk(c iscsiDiskUnmounter, mntPath string) error {
 	}
 
 	for _, portal := range portals {
-				logout := []string{"-m", "node", "-p", portal, "-T", iqn, "--logout"}
-				delete := []string{"-m", "node", "-p", portal, "-T", iqn, "-o", "delete"}
+		logoutArgs := []string{"-m", "node", "-p", portal, "-T", iqn, "--logout"}
+		deleteArgs := []string{"-m", "node", "-p", portal, "-T", iqn, "-o", "delete"}
 		if found {
-					logout = append(logout, []string{"-I", iface}...)
-					delete = append(delete, []string{"-I", iface}...)
+			logoutArgs = append(logoutArgs, []string{"-I", iface}...)
+			deleteArgs = append(deleteArgs, []string{"-I", iface}...)
 		}
 		glog.Infof("iscsi: log out target %s iqn %s iface %s", portal, iqn, iface)
-				out, err := c.exec.Run("iscsiadm", logout...)
+		out, err := c.exec.Run("iscsiadm", logoutArgs...)
 		if err != nil {
 			glog.Errorf("iscsi: failed to detach disk Error: %s", string(out))
 		}
 		// Delete the node record
 		glog.Infof("iscsi: delete node record target %s iqn %s", portal, iqn)
-				out, err = c.exec.Run("iscsiadm", delete...)
+		out, err = c.exec.Run("iscsiadm", deleteArgs...)
 		if err != nil {
 			glog.Errorf("iscsi: failed to delete node record Error: %s", string(out))
 		}
@@ -405,27 +415,24 @@ func (util *ISCSIUtil) DetachDisk(c iscsiDiskUnmounter, mntPath string) error {
 	// Delete the iface after all sessions have logged out
 	// If the iface is not created via iscsi plugin, skip to delete
 	if initiatorName != "" && found && iface == (portals[0]+":"+volName) {
-				delete := []string{"-m", "iface", "-I", iface, "-o", "delete"}
-				out, err := c.exec.Run("iscsiadm", delete...)
+		deleteArgs := []string{"-m", "iface", "-I", iface, "-o", "delete"}
+		out, err := c.exec.Run("iscsiadm", deleteArgs...)
 		if err != nil {
 			glog.Errorf("iscsi: failed to delete iface Error: %s", string(out))
 		}
 	}
 
-		}
-	}
 	return nil
 }
 
 func extractTransportname(ifaceOutput string) (iscsiTransport string) {
 	re := regexp.MustCompile(`iface.transport_name = (.*)\n`)
 
-	rex_output := re.FindStringSubmatch(ifaceOutput)
-	if rex_output != nil {
-		iscsiTransport = rex_output[1]
-	} else {
+	rexOutput := re.FindStringSubmatch(ifaceOutput)
+	if rexOutput == nil {
 		return ""
 	}
+	iscsiTransport = rexOutput[1]
 
 	// While iface.transport_name is a required parameter, handle it being unspecified anyways
 	if iscsiTransport == "<empty>" {
@@ -452,9 +459,9 @@ func extractDeviceAndPrefix(mntPath string) (string, string, error) {
 func extractIface(mntPath string) (string, bool) {
 	re := regexp.MustCompile(`.+/iface-([^/]+)/.+`)
 
-	re_output := re.FindStringSubmatch(mntPath)
-	if re_output != nil {
-		return re_output[1], true
+	reOutput := re.FindStringSubmatch(mntPath)
+	if reOutput != nil {
+		return reOutput[1], true
 	}
 
 	return "", false