csi: fix unpopulated fields in List Volumes API

The list stub object for volumes in `nomad/structs` did not match the stub
object in `api`. The `api` package also did not include the current
readers/writers fields that are expected by the UI. True up the two objects and
add the previously undocumented fields to the docs.

api/csi.go

@@ -384,6 +384,8 @@ type CSIVolumeListStub struct {
 	Topologies          []*CSITopology
 	AccessMode          CSIVolumeAccessMode
 	AttachmentMode      CSIVolumeAttachmentMode
+	CurrentReaders      int
+	CurrentWriters      int
 	Schedulable         bool
 	PluginID            string
 	Provider            string

nomad/structs/csi.go

@@ -367,12 +367,15 @@ type CSIVolListStub struct {
 	Schedulable         bool
 	PluginID            string
 	Provider            string
+	ControllerRequired  bool
 	ControllersHealthy  int
 	ControllersExpected int
 	NodesHealthy        int
 	NodesExpected       int
-	CreateIndex         uint64
-	ModifyIndex         uint64
+	ResourceExhausted   time.Time
+
+	CreateIndex uint64
+	ModifyIndex uint64
 }
 
 // NewCSIVolume creates the volume struct. No side-effects
@@ -409,7 +412,7 @@ func (v *CSIVolume) RemoteID() string {
 }
 
 func (v *CSIVolume) Stub() *CSIVolListStub {
-	stub := CSIVolListStub{
+	return &CSIVolListStub{
 		ID:                  v.ID,
 		Namespace:           v.Namespace,
 		Name:                v.Name,
@@ -422,15 +425,15 @@ func (v *CSIVolume) Stub() *CSIVolListStub {
 		Schedulable:         v.Schedulable,
 		PluginID:            v.PluginID,
 		Provider:            v.Provider,
+		ControllerRequired:  v.ControllerRequired,
 		ControllersHealthy:  v.ControllersHealthy,
 		ControllersExpected: v.ControllersExpected,
 		NodesHealthy:        v.NodesHealthy,
 		NodesExpected:       v.NodesExpected,
+		ResourceExhausted:   v.ResourceExhausted,
 		CreateIndex:         v.CreateIndex,
 		ModifyIndex:         v.ModifyIndex,
 	}
-
-	return &stub
 }
 
 // ReadSchedulable determines if the volume is potentially schedulable

website/content/api-docs/volumes.mdx

@@ -78,6 +78,8 @@ $ curl \
     ],
     "AccessMode": "multi-node-single-writer",
     "AttachmentMode": "file-system",
+    "CurrentReaders": 2,
+    "CurrentWriters": 1,
     "Schedulable": true,
     "PluginID": "plugin-id1",
     "Provider": "ebs",