vSphere: fix crash due to disk without a datastore

Previously, we assumed all disks of types
VirtualDiskFlatVer1BackingInfo, VirtualDiskFlatVer2BackingInfo and
VirtualDiskRawDiskMappingVer1BackingInfo are located on a datastore. The
only exception was disks of type VirtualDiskRawDiskVer2BackingInfo for
which we didn't assume they are located on a datastore but for them RDM
is set to true and so we have a critical concern saying VMs which such
disks cannot be migrated.

However, the 'Datastore' property is optional and according to the
vSphere documentation: "If the file is not located on a datastore, then
this reference is null.". We noticed that this could actually happen,
even though we were not able to reproduce it on our development
environments, and once it happens forklift-controller crashes while
creating the inventory.

Therefore this PR introduces the following changes:
1. Make the code that builds the inventory more robust in terms of
   handling VMs with disks that are not located on a datastore
2. Add a critical concern for such VMs with disks that are not located
   on a datastore, saying such VMs cannot be migrated (later on we will
   anyway fail the validation of a plan due to unmapped storage in this
   case, even if we don't block migration of VMs with critical concerns)

Signed-off-by: Arik Hadas <[email protected]>

pkg/controller/provider/container/vsphere/model.go

@@ -688,44 +688,50 @@ func (v *VmAdapter) updateDisks(devArray *types.ArrayOfVirtualDevice) {
 			switch disk.Backing.(type) {
 			case *types.VirtualDiskFlatVer1BackingInfo:
 				backing := disk.Backing.(*types.VirtualDiskFlatVer1BackingInfo)
-				datastoreId, _ := sanitize(backing.Datastore.Value)
 				md := model.Disk{
 					Key:      disk.Key,
 					File:     backing.FileName,
 					Capacity: disk.CapacityInBytes,
-					Datastore: model.Ref{
+				}
+				if backing.Datastore != nil {
+					datastoreId, _ := sanitize(backing.Datastore.Value)
+					md.Datastore = model.Ref{
 						Kind: model.DsKind,
 						ID:   datastoreId,
-					},
+					}
 				}
 				disks = append(disks, md)
 			case *types.VirtualDiskFlatVer2BackingInfo:
 				backing := disk.Backing.(*types.VirtualDiskFlatVer2BackingInfo)
-				datastoreId, _ := sanitize(backing.Datastore.Value)
 				md := model.Disk{
 					Key:      disk.Key,
 					File:     backing.FileName,
 					Capacity: disk.CapacityInBytes,
 					Shared:   backing.Sharing != "sharingNone",
-					Datastore: model.Ref{
+				}
+				if backing.Datastore != nil {
+					datastoreId, _ := sanitize(backing.Datastore.Value)
+					md.Datastore = model.Ref{
 						Kind: model.DsKind,
 						ID:   datastoreId,
-					},
+					}
 				}
 				disks = append(disks, md)
 			case *types.VirtualDiskRawDiskMappingVer1BackingInfo:
 				backing := disk.Backing.(*types.VirtualDiskRawDiskMappingVer1BackingInfo)
-				datastoreId, _ := sanitize(backing.Datastore.Value)
 				md := model.Disk{
 					Key:      disk.Key,
 					File:     backing.FileName,
 					Capacity: disk.CapacityInBytes,
 					Shared:   backing.Sharing != "sharingNone",
-					Datastore: model.Ref{
+					RDM:      true,
+				}
+				if backing.Datastore != nil {
+					datastoreId, _ := sanitize(backing.Datastore.Value)
+					md.Datastore = model.Ref{
 						Kind: model.DsKind,
 						ID:   datastoreId,
-					},
-					RDM: true,
+					}
 				}
 				disks = append(disks, md)
 			case *types.VirtualDiskRawDiskVer2BackingInfo:

validation/policies/io/konveyor/forklift/vmware/datastore.rego

@@ -0,0 +1,15 @@
+package io.konveyor.forklift.vmware
+
+null_datastore {
+    some i
+    count(input.disks[i].datastore.id) == 0
+}
+
+concerns[flag] {
+    null_datastore
+    flag := {
+        "category": "Critical",
+        "label": "Disk is not located on a datastore",
+        "assessment": "The VM is configured with a disk that is not located on a datastore. The VM cannot be migrated"
+    }
+}

validation/policies/io/konveyor/forklift/vmware/datastore_test.rego

@@ -0,0 +1,33 @@
+package io.konveyor.forklift.vmware
+
+test_with_no_disks {
+    mock_vm := {
+        "name": "test",
+        "disks": []
+    }
+    results := concerns with input as mock_vm
+    count(results) == 0
+}
+
+test_with_valid_disk {
+    mock_vm := {
+        "name": "test",
+        "disks": [
+            { "datastore": { "kind": "datastore", "id": "datastore-1" } }
+        ]
+    }
+    results := concerns with input as mock_vm
+    count(results) == 0
+}
+
+test_with_invalid_disk {
+    mock_vm := {
+        "name": "test",
+        "disks": [
+            { "datastore": { "kind": "datastore", "id": "datastore-1" } },
+            { "datastore": { "kind": "", "id": "" } },
+        ]
+    }
+    results := concerns with input as mock_vm
+    count(results) == 1
+}