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toolbox - VMware guest tools library for Go

Overview

The toolbox library is a lightweight, extensible framework for implementing VMware guest tools functionality. The primary focus of the library is the implementation of VM guest RPC protocols, transport and dispatch. These protocols are undocumented for the most part, but open-vm-tools serves as a reference implementation. The toolbox provides default implementations of the supported RPCs, which can be overridden and/or extended by consumers.

Supported features

Feature list from the perspective of vSphere public API interaction. The properties, objects and methods listed are relative to the VirtualMachine managed object type.

guest.toolsVersionStatus property

The toolbox reports version as guestToolsUnmanaged.

See ToolsVersionStatus

guest.toolsRunningStatus and guest.guestState properties

The VMX determines these values based on the toolbox's response to the ping RPC.

guest.ipAddress property

The VMX requests this value via the Set_Option broadcastIP RPC.

The default value can be overridden by setting the Service.PrimaryIP function.

See vim.vm.GuestInfo

guest.net property

This data is pushed to the VMX using the SendGuestInfo(INFO_IPADDRESS_V3) RPC.

See GuestNicInfo.

ShutdownGuest and RebootGuest methods

The PowerCommandHandler provides power hooks for customized guest shutdown and reboot.

GuestAuthManager object

Not supported, but authentication can be customized.

See vim.vm.guest.AuthManager

GuestFileManager object

Method Supported Client Examples
ChangeFileAttributesInGuest Yes chmod
chown
touch
CreateTemporaryDirectoryInGuest Yes mktemp
CreateTemporaryFileInGuest Yes mktemp
DeleteDirectoryInGuest Yes rmdir
DeleteFileInGuest Yes rm
InitiateFileTransferFromGuest Yes download
InitiateFileTransferToGuest Yes upload
ListFilesInGuest Yes ls
MakeDirectoryInGuest Yes mkdir
MoveDirectoryInGuest Yes mv
MoveFileInGuest Yes mv

See vim.vm.guest.FileManager

GuestProcessManager

Currently, the ListProcessesInGuest and TerminateProcessInGuest methods only apply those processes and goroutines started by StartProgramInGuest.

Method Supported Client Examples
ListProcessesInGuest Yes ps
ReadEnvironmentVariableInGuest Yes getenv
StartProgramInGuest Yes start
TerminateProcessInGuest Yes kill

See vim.vm.guest.ProcessManager

Extensions

Authentication

Guest operations can be authenticated using the toolbox.CommandServer.Authenticate hook.

Go functions

The toolbox ProcessManager can manage both OS processes and Go functions running as go routines.

File handlers

The hgfs.FileHandler interface can be used to customize file transfer.

Process I/O

The toolbox provides support for I/O redirection without the use of disk files within the guest. Access to stdin, stdout and stderr streams is implemented as an hgfs.FileHandler within the ProcessManager.

See toolbox.Client and govc guest.run

http.RoundTripper

Building on top of the process I/O functionality, toolbox.NewProcessRoundTrip can be used to start a Go function to implement the http.RoundTripper interface over vmx guest RPC. This makes it possible to use the Go http.Client without network access to the VM or to a port that is bound to the guest's loopback address. It is intended for use with bootstrap configuration for example.

Directory archives

The toolbox provides support for transferring directories to and from guests as gzip'd tar streams, without writing the tar file itself to the guest file system. Archive supports is implemented as an hgfs.FileHandler within the hgfs package. See hgfs.NewArchiveHandler

Linux /proc file access

With standard vmware-tools, the file size is reported as returned by stat() and hence a Content-Length header of size 0. The toolbox reports /proc file size as hgfs.LargePacketMax to enable transfer of these files. Note that if the file data fits within in hgfs.LargePacketMax, the Content-Length header will be correct as it is sent after the first read by the vmx. However, if the file data exceeds hgfs.LargePacketMax, the Content-Length will be hgfs.LargePacketMax, and client side will truncate to that size.

Testing

The Go tests cover most of the toolbox code and can be run on any Linux or MacOSX machine, virtual or otherwise.

To test the toolbox with vSphere API interaction, it must be run inside a VM managed by vSphere without the standard vmtoolsd running.

The toolbox-test.sh can be used to run the full suite of toolbox tests with vSphere API interaction. Use the -s flag to start the standalone version of the toolbox and leave it running, to test vSphere interaction without running the test suite.

Consumers of the toolbox library

Supported guests

The toolbox guest RPC implementations tend to be simple and portable thanks to the Go standard library, but are only supported on Linux currently. Support for other guests, such as Windows, has been kept in mind but not yet tested.

Supported vSphere Versions

The toolbox is supported with vSphere 6.0 and 6.5, but may function with older versions.