chapi: add nfs mount endpoint (#117)

* chapi: add nfs mount endpoint
* Problem:
  * need capability in chapi to perform nfs mounts
* Implementation:
  * add endpoint which performs just mount without device checking.
* Testing: tested with nfs volumes using csi driver.
* Review: gcostea, rkumar
Signed-off-by: Shiva Krishna, Merla <[email protected]>

* Update endpoint for darwin flavor as well to avoid linter errors

Signed-off-by: Shiva Krishna, Merla <[email protected]>

Author: shivamerla

chapi/chapidriver.go

@@ -18,6 +18,7 @@ type Driver interface {
 	DeleteDevice(device *model.Device) error
 	OfflineDevice(device *model.Device) error
 	MountDevice(device *model.Device, mountPoint string, mountOptions []string, fsOpts *model.FilesystemOpts) (*model.Mount, error) // Idempotent
+	MountNFSVolume(source string, target string, mountOptions []string) error                                                       // Idempotent
 	BindMount(mountPoint string, newMountPoint string, rbind bool) error                                                            // Idempotent
 	BindUnmount(mountPoint string) error                                                                                            // Idempotent
 	UnmountDevice(device *model.Device, mountPoint string) (*model.Mount, error)                                                    // Idempotent

chapi/chapidriver_darwin.go

@@ -33,7 +33,7 @@ func (driver *MacDriver) GetMountOptions(device *model.Device, mountPoint string
 }
 
 // GetHostNetworks reports the networks on this host
-func (driver *MacDriver) GetHostNetworks() ([]*model.Network, error) {
+func (driver *MacDriver) GetHostNetworks() ([]*model.NetworkInterface, error) {
 	return nil, fmt.Errorf("not implemented")
 }
 
@@ -131,3 +131,8 @@ func (driver *MacDriver) BindUnmount(mountPoint string) error {
 func (driver *MacDriver) ExpandDevice(targetPath string, volAccessType model.VolumeAccessType) error {
 	return fmt.Errorf("not implemented")
 }
+
+// MountNFSVolume mounts NFS share onto given target path
+func (driver *MacDriver) MountNFSVolume(source string, targetPath string, mountOptions []string) error {
+	return nil
+}

chapi/chapidriver_fake.go

@@ -154,3 +154,8 @@ func (driver *FakeDriver) OfflineDevice(device *model.Device) error {
 func (driver *FakeDriver) ExpandDevice(targetPath string, volAccessType model.VolumeAccessType) error {
 	return nil
 }
+
+// MountNFSVolume mounts NFS share onto given target path
+func (driver *FakeDriver) MountNFSVolume(source string, targetPath string, mountOptions []string) error {
+	return nil
+}

chapi/chapidriver_linux.go

@@ -235,6 +235,17 @@ func (driver *LinuxDriver) GetMountsForDevice(device *model.Device) ([]*model.Mo
 	return linux.GetMountPointsForDevices(devices)
 }
 
+func (driver *LinuxDriver) MountNFSVolume(source string, targetPath string, mountOptions []string) error {
+	log.Tracef(">>>>> MountNFSVolume called with source %s target %s options %v: ", source, targetPath, mountOptions)
+	defer log.Trace("<<<<< MountNFSVolume")
+
+	err := linux.MountNFSShare(source, targetPath, mountOptions)
+	if err != nil {
+		return fmt.Errorf("Error mounting nfs share %s at %s, err %s", source, targetPath, err.Error())
+	}
+	return nil
+}
+
 // MountDevice mounts the given device to the given mount point. This must be idempotent.
 func (driver *LinuxDriver) MountDevice(device *model.Device, mountPoint string, mountOptions []string, fsOpts *model.FilesystemOpts) (*model.Mount, error) {
 	log.Tracef(">>>>> MountDevice, device: %+v, mountPoint: %s, mountOptions: %v, fsOpts: %+v", device, mountPoint, mountOptions, fsOpts)

linux/mount.go

@@ -570,6 +570,28 @@ func MountDeviceWithFileSystem(devPath string, mountPoint string, options []stri
 	return mount, nil
 }
 
+func MountNFSShare(source string, targetPath string, options []string) error {
+	log.Tracef(">>>>> MountNFSShare called with source %s target %s", source, targetPath)
+	defer log.Tracef("<<<<< MountNFSShare")
+
+	args := []string{source, targetPath}
+	optionArgs := []string{}
+	if len(options) != 0 {
+		optionArgs = append([]string{"-o"}, strings.Join(options, ","))
+	}
+	args = append(optionArgs, args...)
+	_, _, err := util.ExecCommandOutput(mountCommand, args)
+	if err != nil {
+		return err
+	}
+	// verify that mount is successful
+	err = verifyMount(source, targetPath)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 func performMount(devPath string, mountPoint string, options []string) (*model.Mount, error) {
 	args := []string{devPath, mountPoint}
 	optionArgs := []string{}
@@ -694,15 +716,17 @@ func verifyUnMount(mountPoint string) error {
 	log.Tracef("%s is unmounted", mountPoint)
 	return nil
 }
+
 func verifyMount(devPath, mountPoint string) error {
 	mountedDevice, err := GetDeviceFromMountPoint(mountPoint)
 	if err != nil {
 		return err
 	}
-	if mountedDevice != "" {
-		log.Tracef("%s is mounted at %s", devPath, mountPoint)
+	if mountedDevice == "" {
+		return fmt.Errorf("device %s is not mounted at %s", devPath, mountPoint)
 	}
-	return err
+	log.Tracef("%s is mounted at %s", devPath, mountPoint)
+	return nil
 }
 
 // GetFsType returns filesytem type for a given mount object