Re: [PATCH 1/3] KVM Test: Introduce a helper class to run a test in the background

[Lucas Meneghel Rodrigues <lmr@redhat.com>]

On Fri, 2010-11-26 at 21:01 -0200, Lucas Meneghel Rodrigues wrote:
> Sometimes, we need to run a test when doing operations on a running VM
> (such as migrate the vm during its rebooting ). So this patch introduces
> a simple warpper BackgroundTest to run a specified test in the background
> through a dedicated thread, it also records the exception raised in the
> thead and raise it when master call join().

Since we've spent some time looking into this and noone came up with a
better solution, I'm applying Jason's series. In order to run the tests
in parallel, on your test set you can put either:

only migrate.with_file_transfer
or
only migrate.with_reboot

Provided, of course, that you already had a vm installed with autotest.
If you don't you probably want to include the unattended_install.cdrom
test before.

Cheers!

Lucas

> Changes from v1:
> - Rebase against latest upstream
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  client/tests/kvm/kvm_test_utils.py |   49 +++++++++++++++++++++++++++++++++++-
>  1 files changed, 48 insertions(+), 1 deletions(-)
> 
> diff --git a/client/tests/kvm/kvm_test_utils.py b/client/tests/kvm/kvm_test_utils.py
> index e7c8d33..218bf31 100644
> --- a/client/tests/kvm/kvm_test_utils.py
> +++ b/client/tests/kvm/kvm_test_utils.py
> @@ -21,7 +21,7 @@ More specifically:
>  @copyright: 2008-2009 Red Hat Inc.
>  """
>  
> -import time, os, logging, re, commands, signal
> +import time, os, logging, re, commands, signal, threading
>  from autotest_lib.client.common_lib import error
>  from autotest_lib.client.bin import utils
>  import kvm_utils, kvm_vm, kvm_subprocess, scan_results
> @@ -564,6 +564,53 @@ def run_autotest(vm, session, control_path, timeout, outputdir):
>          raise error.TestFail(e_msg)
>  
> 
> +class BackgroundTest(object):
> +    """
> +    This class would run a test in background through a dedicated thread.
> +    """
> +
> +    def __init__(self, func, params):
> +        """
> +        Initialize the object and set a few attributes.
> +        """
> +        self.thread = threading.Thread(target=self.launch,
> +                                       args=(func, params))
> +        self.exception = None
> +
> +
> +    def launch(self, func, params):
> +        """
> +        Catch and record the exception.
> +        """
> +        try:
> +            func(*params)
> +        except Exception, e:
> +            self.exception = e
> +
> +
> +    def start(self):
> +        """
> +        Run func(params) in a dedicated thread
> +        """
> +        self.thread.start()
> +
> +
> +    def join(self):
> +        """
> +        Wait for the join of thread and raise its exception if any.
> +        """
> +        self.thread.join()
> +        if self.exception:
> +            raise self.exception
> +
> +
> +    def is_alive(self):
> +        """
> +        Check whether the test is still alive.
> +        """
> +        return self.thread.is_alive()
> +
> +
>  def get_loss_ratio(output):
>      """
>      Get the packet loss ratio from the output of ping