Synnefo » snf-ganeti

# List of all hooks

_hooks = []

def LoadHooks():

  """Load all QA hooks.

  """

  hooks_dir = qa_config.get('options', {}).get('hooks-dir', None)

  if not hooks_dir:

    return

  if hooks_dir not in sys.path:

    sys.path.insert(0, hooks_dir)

  for name in utils.ListVisibleFiles(hooks_dir):

    if name.endswith('.py'):

      # Load and instanciate hook

      print "Loading hook %s" % name

      _hooks.append(__import__(name[:-3], None, None, ['']).hook())

class QaHookContext:

  """Definition of context passed to hooks.

  """

  name = None

  phase = None

  success = None

  args = None

  kwargs = None

def _CallHooks(ctx):

  """Calls all hooks with the given context.

  """

  if not _hooks:

    return

  name = "%s-%s" % (ctx.phase, ctx.name)

  if ctx.success is not None:

    msg = "%s (success=%s)" % (name, ctx.success)

  else:

    msg = name

  print FormatInfo("Begin %s" % msg)

  for hook in _hooks:

    hook.run(ctx)

  print FormatInfo("End %s" % name)

def DefineHook(name):

  """Wraps a function with calls to hooks.

  Usage: prefix function with @qa_utils.DefineHook(...)

  This is based on PEP 318, "Decorators for Functions and Methods".

  """

  def wrapper(fn):

    def new_f(*args, **kwargs):

      # Create context

      ctx = QaHookContext()

      ctx.name = name

      ctx.phase = 'pre'

      ctx.args = args

      ctx.kwargs = kwargs

      _CallHooks(ctx)

      try:

        ctx.phase = 'post'

        ctx.success = True

        try:

          # Call real function

          return fn(*args, **kwargs)

        except:

          ctx.success = False

          raise

      finally:

        _CallHooks(ctx)

    # Override function metadata

    new_f.func_name = fn.func_name

    new_f.func_doc = fn.func_doc

    return new_f

  return wrapper