api: Add a method for extending VMDK

Signed-off-by: Stoyan Zhelyazkov <stoyan.zhelyazkov@broadcom.com>

govc/USAGE.md

@@ -81,6 +81,7 @@ but appear via `govc $cmd -h`:
  - [datastore.cp](#datastorecp)
  - [datastore.create](#datastorecreate)
  - [datastore.disk.create](#datastorediskcreate)
+ - [datastore.disk.extend](#datastorediskextend)
  - [datastore.disk.inflate](#datastorediskinflate)
  - [datastore.disk.info](#datastorediskinfo)
  - [datastore.disk.shrink](#datastorediskshrink)
@@ -1222,6 +1223,23 @@ Options:
   -uuid=                 Disk UUID
 ```
 
+## datastore.disk.extend
+
+```
+Usage: govc datastore.disk.extend [OPTIONS] VMDK
+
+Extend VMDK on DS.
+
+Examples:
+  govc datastore.disk.extend disks/disk1.vmdk -size=24G
+  govc datastore.disk.extend disks/disk1.vmdk -size=24G -eagerZero=true
+
+Options:
+  -ds=                   Datastore [GOVC_DATASTORE]
+  -eagerZero=false       If true, the extended part of the disk will be explicitly filled with zeroes
+  -size=0B               New capacity for the disk
+```
+
 ## datastore.disk.inflate
 
 ```

govc/datastore/disk/extend.go

@@ -0,0 +1,92 @@
+/*
+Copyright (c) 2024-2024 VMware, Inc. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package disk
+
+import (
+	"context"
+	"flag"
+	"fmt"
+
+	"github.com/vmware/govmomi/units"
+
+	"github.com/vmware/govmomi/govc/cli"
+	"github.com/vmware/govmomi/govc/flags"
+	"github.com/vmware/govmomi/object"
+)
+
+type extend struct {
+	*flags.DatastoreFlag
+	Bytes     units.ByteSize
+	EagerZero bool
+}
+
+func init() {
+	cli.Register("datastore.disk.extend", &extend{})
+}
+
+func (cmd *extend) Register(ctx context.Context, f *flag.FlagSet) {
+	cmd.DatastoreFlag, ctx = flags.NewDatastoreFlag(ctx)
+	cmd.DatastoreFlag.Register(ctx, f)
+
+	f.Var(&cmd.Bytes, "size", "New capacity for the disk")
+	f.BoolVar(&cmd.EagerZero, "eagerZero", false, "If true, the extended part of the disk will be explicitly filled with zeroes")
+}
+
+func (cmd *extend) Process(ctx context.Context) error {
+	return cmd.DatastoreFlag.Process(ctx)
+}
+
+func (cmd *extend) Usage() string {
+	return "VMDK"
+}
+
+func (cmd *extend) Description() string {
+	return `Extend VMDK on DS.
+
+Examples:
+  govc datastore.disk.extend disks/disk1.vmdk -size=24G
+  govc datastore.disk.extend disks/disk1.vmdk -size=24G -eagerZero=true`
+}
+
+func (cmd *extend) Run(ctx context.Context, f *flag.FlagSet) error {
+	if f.NArg() == 0 {
+		return flag.ErrHelp
+	}
+
+	dc, err := cmd.Datacenter()
+	if err != nil {
+		return err
+	}
+
+	ds, err := cmd.Datastore()
+	if err != nil {
+		return err
+	}
+
+	m := object.NewVirtualDiskManager(ds.Client())
+	path := ds.Path(f.Arg(0))
+	task, err := m.ExtendVirtualDisk(ctx, path, dc, int64(cmd.Bytes/1024), &cmd.EagerZero)
+	if err != nil {
+		return err
+	}
+
+	logger := cmd.ProgressLogger(fmt.Sprintf("Extending %s...", path))
+	defer logger.Wait()
+
+	_, err = task.WaitForResult(ctx, logger)
+	return err
+}

object/virtual_disk_manager.go

@@ -94,6 +94,33 @@ func (m VirtualDiskManager) CreateVirtualDisk(
 	return NewTask(m.c, res.Returnval), nil
 }
 
+// ExtendVirtualDisk extends an existing virtual disk.
+func (m VirtualDiskManager) ExtendVirtualDisk(
+	ctx context.Context,
+	name string, datacenter *Datacenter,
+	capacityKb int64,
+	eagerZero *bool) (*Task, error) {
+
+	req := types.ExtendVirtualDisk_Task{
+		This:          m.Reference(),
+		Name:          name,
+		NewCapacityKb: capacityKb,
+		EagerZero:     eagerZero,
+	}
+
+	if datacenter != nil {
+		ref := datacenter.Reference()
+		req.Datacenter = &ref
+	}
+
+	res, err := methods.ExtendVirtualDisk_Task(ctx, m.c, &req)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewTask(m.c, res.Returnval), nil
+}
+
 // MoveVirtualDisk moves a virtual disk.
 func (m VirtualDiskManager) MoveVirtualDisk(
 	ctx context.Context,

simulator/virtual_disk_manager.go

@@ -19,6 +19,7 @@ package simulator
 import (
 	"fmt"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/google/uuid"
@@ -76,12 +77,59 @@ func vdmCreateVirtualDisk(op types.VirtualDeviceConfigSpecFileOperation, req *ty
 			return fm.fault(name, err, new(types.CannotCreateFile))
 		}
 
+		if req.Spec != nil {
+			var spec interface{} = req.Spec
+			fileBackedSpec, ok := spec.(*types.FileBackedVirtualDiskSpec)
+
+			if !ok {
+				return fm.fault(name, nil, new(types.FileFault))
+			}
+
+			if _, err = f.WriteString(strconv.FormatInt(fileBackedSpec.CapacityKb, 10)); err != nil {
+				return fm.fault(name, err, new(types.FileFault))
+			}
+		}
+
 		_ = f.Close()
 	}
 
 	return nil
 }
 
+func vdmExtendVirtualDisk(req *types.ExtendVirtualDisk_Task) types.BaseMethodFault {
+	fm := Map.FileManager()
+
+	file, fault := fm.resolve(req.Datacenter, req.Name)
+	if fault != nil {
+		return fault
+	}
+
+	for _, name := range vdmNames(file) {
+		_, err := os.Stat(name)
+		if err == nil {
+			content, err := os.ReadFile(name)
+			if err != nil {
+				return fm.fault(name, err, new(types.FileFault))
+			}
+
+			capacity, err := strconv.Atoi(string(content))
+			if err != nil {
+				return fm.fault(name, err, new(types.FileFault))
+			}
+
+			if int64(capacity) > req.NewCapacityKb {
+				// cannot shrink disk
+				return fm.fault(name, nil, new(types.FileFault))
+			}
+			return nil
+		} else {
+			return fm.fault(name, nil, new(types.FileNotFound))
+		}
+	}
+
+	return nil
+}
+
 func (m *VirtualDiskManager) CreateVirtualDiskTask(ctx *Context, req *types.CreateVirtualDisk_Task) soap.HasFault {
 	task := CreateTask(m, "createVirtualDisk", func(*Task) (types.AnyType, types.BaseMethodFault) {
 		if err := vdmCreateVirtualDisk(types.VirtualDeviceConfigSpecFileOperationCreate, req); err != nil {
@@ -97,6 +145,21 @@ func (m *VirtualDiskManager) CreateVirtualDiskTask(ctx *Context, req *types.Crea
 	}
 }
 
+func (m *VirtualDiskManager) ExtendVirtualDiskTask(ctx *Context, req *types.ExtendVirtualDisk_Task) soap.HasFault {
+	task := CreateTask(m, "extendVirtualDisk", func(*Task) (types.AnyType, types.BaseMethodFault) {
+		if err := vdmExtendVirtualDisk(req); err != nil {
+			return "", err
+		}
+		return req.Name, nil
+	})
+
+	return &methods.ExtendVirtualDisk_TaskBody{
+		Res: &types.ExtendVirtualDisk_TaskResponse{
+			Returnval: task.Run(ctx),
+		},
+	}
+}
+
 func (m *VirtualDiskManager) DeleteVirtualDiskTask(ctx *Context, req *types.DeleteVirtualDisk_Task) soap.HasFault {
 	task := CreateTask(m, "deleteVirtualDisk", func(*Task) (types.AnyType, types.BaseMethodFault) {
 		fm := Map.FileManager()

simulator/virtual_disk_manager_test.go

@@ -86,6 +86,32 @@ func TestVirtualDiskManager(t *testing.T) {
 	}
 
 	qname := name
+	for i, fail := range []bool{false, true, true} {
+		if i == 1 {
+			spec.CapacityKb = 0
+		}
+
+		if i == 2 {
+			qname += "_missing_file"
+		}
+		task, err := dm.ExtendVirtualDisk(ctx, qname, nil, spec.CapacityKb*2, nil)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = task.Wait(ctx)
+		if fail {
+			if err == nil {
+				t.Error("expected error")
+			}
+		} else {
+			if err != nil {
+				t.Error(err)
+			}
+		}
+	}
+
+	qname = name
 	for _, fail := range []bool{false, true} {
 		id, err := dm.QueryVirtualDiskUuid(ctx, qname, nil)
 		if fail {