Re: [Autotest] [PATCH 05/11] virt: Introducing libvirt VM class

[Amos Kong <akong@redhat.com>]

On 10/12/2011 05:07 AM, Lucas Meneghel Rodrigues wrote:
> This is a first attempt at providing a libvirt VM class,
> in order to implement the needed methods for virt testing.
> With this class, we will be able to implement a libvirt
> test, that behaves similarly to the KVM test.
>
> As of implementation details, libvirt_vm uses virsh
> (a userspace program written on top of libvirt) to
> do domain start, stop, verification of status and
> other common operations. The reason why virsh was
> used is to get more coverage of the userspace stack
> that libvirt offers, and also to catch issues that
> virsh users would catch.
>
> Signed-off-by: Lucas Meneghel Rodrigues<lmr@redhat.com>
> ---
>   client/virt/libvirt_vm.py | 1232 +++++++++++++++++++++++++++++++++++++++++++++
>   1 files changed, 1232 insertions(+), 0 deletions(-)
>   create mode 100644 client/virt/libvirt_vm.py
>
> diff --git a/client/virt/libvirt_vm.py b/client/virt/libvirt_vm.py
> new file mode 100644
> index 0000000..bed512f
> --- /dev/null
> +++ b/client/virt/libvirt_vm.py
> @@ -0,0 +1,1232 @@
> +"""
> +Utility classes and functions to handle Virtual Machine creation using qemu.
> +
> +@copyright: 2008-2009 Red Hat Inc.
> +"""
> +
> +import time, os, logging, fcntl, re, commands
> +from autotest_lib.client.common_lib import error
> +from autotest_lib.client.bin import utils, os_dep
> +from xml.dom import minidom
> +import virt_utils, virt_vm, aexpect
> +
> +DEBUG = False
> +try:
> +    VIRSH_EXEC = os_dep.command("virsh")
> +except ValueError:
> +    VIRSH_EXEC = None
> +
> +
> +def libvirtd_restart():
> +    """
> +    Restart libvirt daemon.
> +    """
> +    try:
> +        utils.run("service libvirtd restart")
> +        logging.debug("Restarted libvirtd successfuly")
> +        return True
> +    except error.CmdError, detail:
> +        logging.error("Failed to restart libvirtd: %s" % detail)
> +        return False
> +
> +
> +def virsh_cmd(cmd):
> +    if VIRSH_EXEC is None:
> +        raise ValueError('Missing command: virsh')
> +    cmd_result = utils.run("%s %s" % (VIRSH_EXEC, cmd), ignore_status=True,
> +                           verbose=DEBUG)
> +    if DEBUG:
> +        if cmd_result.stdout.strip():
> +            logging.debug("stdout: %s", cmd_result.stdout.strip())
> +        if cmd_result.stderr.strip():
> +            logging.debug("stderr: %s", cmd_result.stderr.strip())
> +    return cmd_result.stdout.strip()
> +
> +
> +def virsh_uri():
> +    """
> +    Return the hypervisor canonical URI.
> +    """
> +    return virsh_cmd("uri")
> +
> +
> +def virsh_hostname():
> +    """
> +    Return the hypervisor hostname.
> +    """
> +    return virsh_cmd("hostname")
> +
> +
> +def virsh_domstate(name):
> +    """
> +    Return the state about a running domain.
> +
> +    @param name: VM name
> +    """
> +    return virsh_cmd("domstate %s" % name)
> +
> +
> +def virsh_uuid(name):
> +    """
> +    Return the Converted domain name or id to the domain UUID.
> +
> +    @param name: VM name
> +    """
> +    return virsh_cmd("domuuid %s" % name)
> +
> +
> +def virsh_screenshot(name, filename):
> +    virsh_cmd("screenshot %s %s" % (name, filename))
> +    return filename
> +
> +
> +def virsh_dumpxml(name):
> +    """
> +    Return the domain information as an XML dump.
> +
> +    @param name: VM name
> +    """
> +    return virsh_cmd("dumpxml %s" % name)
> +
> +
> +def virsh_is_alive(name):
> +    """
> +    Return True if the domain is started/alive.
> +
> +    @param name: VM name
> +    """
> +    return not virsh_is_dead(name)
> +
> +
> +def virsh_is_dead(name):
> +    """
> +    Return True if the domain is not started/dead.
> +
> +    @param name: VM name
> +    """
> +    if (virsh_domstate(name) == 'running' or
> +        virsh_domstate(name) == 'idle'):
> +        return False
> +    else:
> +        return True
> +
> +
> +def virsh_suspend(name):
> +    """
> +    Return True on successful domain suspention of VM.
> +
> +    Suspend  a domain. It is kept in memory but will not be scheduled.
> +
> +    @param name: VM name
> +    """
> +    try:
> +        utils.run("virsh suspend %s" % (name))
> +        if virsh_domstate(name) == 'paused':
> +            logging.debug("Suspended VM %s", name)
> +            return True
> +        else:
> +            return False
> +    except error.CmdError:
> +        logging.error("Suspending VM %s failed", name)
> +        return False
> +
> +
> +def virsh_resume(name):
> +    """
> +    Return True on successful domain resumption of VM.
> +
> +    Move a domain out of the suspended state.
> +
> +    @param name: VM name
> +    """
> +    try:
> +        utils.run("virsh resume %s" % (name))
> +        if virsh_is_alive(name):
> +            logging.debug("Resumed VM %s", name)
> +            return True
> +        else:
> +            return False
> +    except error.CmdError:
> +        logging.error("Resume VM %s failed", name)
> +        return False
> +
> +
> +def virsh_start(name, vm):

    def virsh_start(name):

one or two augments here? this function is called with one augment in 
VM.start()

> +    """
> +    Return True on successful domain start.
> +
> +    Start a (previously defined) inactive domain.
> +
> +    @param name: VM name
> +    """
> +    if virsh_is_alive(name):
> +        return
> +    try:
> +        utils.run("virsh start %s" % (name))
> +        return True
> +    except error.CmdError:
> +        logging.error("Start VM %s failed", name)

If the virsh cmd fails, we would got two error message.
They are repeated, how about remove this one? or add a prefix(we would 
know it's an error of virsh cmd)

logging.error("Start VM %s failed", name)
logging.error("VM %s failed to start", self.name)

> +        return False
> +
> +

....
> +
> +class VM(virt_vm.BaseVM):
> +    """
> +    This class handles all basic VM operations for libvirt.
> +    """
> +    def __init__(self, name, params, root_dir, address_cache, state=None):
> +        """
> +        Initialize the object and set a few attributes.
> +
> +        @param name: The name of the object
> +        @param params: A dict containing VM params
> +                (see method make_qemu_command for a full description)

....
> +
> +    def start(self):
> +        """
> +        Starts this VM.
> +        """
> +        if virsh_start(self.name):

^^^^^^^^

> +            if self.wait_for_start():
> +                logging.debug("Started VM %s", self.name)
> +                return True
> +            else:
> +                logging.error("VM %s failed to start", self.name)
> +                return False
> +        else:
> +            logging.error("VM %s failed to start", self.name)

^^^^^^^^

> +            return False
> +
> +
> +    def wait_for_shutdown(self, count=60):
> +        """
> +        Return True on successful domain shutdown.
> +
> +        Wait for a domain to shutdown, libvirt does not block on domain
> +        shutdown so we need to watch for successful completion.
> +
> +        @param name: VM name
> +        @param name: Optional timeout value
> +        """
> +        timeout = count
> +        while count>  0:
> +            # check every 5 seconds
> +            if count % 5 == 0:
> +                if virsh_is_dead(self.name):
> +                    logging.debug("Shutdown took %d seconds", timeout - count)
> +                    return True
> +            count -= 1
> +            time.sleep(1)
> +            logging.debug("Waiting for guest to shutdown %d", count)
> +        return False
> +