Merge pull request #56921 from andyzhangx/flexvolume-windows

Automatic merge from submit-queue (batch tested with PRs 56650, 55813, 56911, 56921, 56871). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

enable flexvolume on Windows node

**What this PR does / why we need it**:
enable flexvolume on Windows node:
current PodVolumeDir is like 
`\var\lib\kubelet\pods\f54c5a74-da63-11e7-b71a-000d3a02c330\volumes\test~hostpath.cmd\flextest`
which is a unix path, with this PR, PodVolumeDir in **windows** kubelet  will be converted into like
`c:\var\lib\kubelet\pods\f54c5a74-da63-11e7-b71a-000d3a02c330\volumes\test~hostpath.cmd\flextest` 

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #56875

**Special notes for your reviewer**:
Detailed steps about how to use flexvolume on Windows with this PR:
https://github.com/andyzhangx/Demo/tree/master/windows/flexvolume

**Release note**:

```
enable flexvolume on Windows node
```

/sig windows

pkg/kubelet/volume_host.go

@@ -19,6 +19,7 @@ package kubelet
 import (
 	"fmt"
 	"net"
+	"runtime"
 
 	"github.com/golang/glog"
 
@@ -91,7 +92,11 @@ func (kvh *kubeletVolumeHost) GetVolumeDevicePluginDir(pluginName string) string
 }
 
 func (kvh *kubeletVolumeHost) GetPodVolumeDir(podUID types.UID, pluginName string, volumeName string) string {
-	return kvh.kubelet.getPodVolumeDir(podUID, pluginName, volumeName)
+	dir := kvh.kubelet.getPodVolumeDir(podUID, pluginName, volumeName)
+	if runtime.GOOS == "windows" {
+		dir = volume.GetWindowsPath(dir)
+	}
+	return dir
 }
 
 func (kvh *kubeletVolumeHost) GetPodVolumeDeviceDir(podUID types.UID, pluginName string) string {

pkg/volume/flexvolume/plugin.go

@@ -19,6 +19,7 @@ package flexvolume
 import (
 	"fmt"
 	"path"
+	"runtime"
 	"strings"
 	"sync"
 
@@ -100,7 +101,11 @@ func (plugin *flexVolumePlugin) Init(host volume.VolumeHost) error {
 func (plugin *flexVolumePlugin) getExecutable() string {
 	parts := strings.Split(plugin.driverName, "/")
 	execName := parts[len(parts)-1]
-	return path.Join(plugin.execPath, execName)
+	execPath := path.Join(plugin.execPath, execName)
+	if runtime.GOOS == "windows" {
+		execPath = volume.GetWindowsPath(execPath)
+	}
+	return execPath
 }
 
 // Name is part of the volume.VolumePlugin interface.

pkg/volume/util.go

@@ -514,3 +514,12 @@ func AccessModesContainedInAll(indexedModes []v1.PersistentVolumeAccessMode, req
 	}
 	return true
 }
+
+// GetWindowsPath get a windows path
+func GetWindowsPath(path string) string {
+	windowsPath := strings.Replace(path, "/", "\\", -1)
+	if strings.HasPrefix(windowsPath, "\\") {
+		windowsPath = "c:" + windowsPath
+	}
+	return windowsPath
+}

pkg/volume/util_test.go

@@ -869,3 +869,34 @@ func TestValidateZone(t *testing.T) {
 		}
 	}
 }
+
+func TestGetWindowsPath(t *testing.T) {
+	tests := []struct {
+		path         string
+		expectedPath string
+	}{
+		{
+			path:         `/var/lib/kubelet/pods/146f8428-83e7-11e7-8dd4-000d3a31dac4/volumes/kubernetes.io~disk`,
+			expectedPath: `c:\var\lib\kubelet\pods\146f8428-83e7-11e7-8dd4-000d3a31dac4\volumes\kubernetes.io~disk`,
+		},
+		{
+			path:         `\var/lib/kubelet/pods/146f8428-83e7-11e7-8dd4-000d3a31dac4\volumes\kubernetes.io~disk`,
+			expectedPath: `c:\var\lib\kubelet\pods\146f8428-83e7-11e7-8dd4-000d3a31dac4\volumes\kubernetes.io~disk`,
+		},
+		{
+			path:         `/`,
+			expectedPath: `c:\`,
+		},
+		{
+			path:         ``,
+			expectedPath: ``,
+		},
+	}
+
+	for _, test := range tests {
+		result := GetWindowsPath(test.path)
+		if result != test.expectedPath {
+			t.Errorf("GetWindowsPath(%v) returned (%v), want (%v)", test.path, result, test.expectedPath)
+		}
+	}
+}