+
+
+def SimpleRetry(expected, fn, delay, timeout, args=None, wait_fn=time.sleep,
+ _time_fn=time.time):
+ """A wrapper over L{Retry} implementing a simpler interface.
+
+ All the parameters are the same as for L{Retry}, except it has one
+ extra argument: expected, which can be either a value (will be
+ compared with the result of the function, or a callable (which will
+ get the result passed and has to return a boolean). If the test is
+ false, we will retry until either the timeout has passed or the
+ tests succeeds. In both cases, the last result from calling the
+ function will be returned.
+
+ Note that this function is not expected to raise any retry-related
+ exceptions, always simply returning values. As such, the function is
+ designed to allow easy wrapping of code that doesn't use retry at
+ all (e.g. "if fn(args)" replaced with "if SimpleRetry(True, fn,
+ ...)".
+
+ @see: L{Retry}
+
+ """
+ rdict = {}
+
+ def helper(*innerargs):
+ # pylint: disable=W0142
+ result = rdict["result"] = fn(*innerargs)
+ if not ((callable(expected) and expected(result)) or result == expected):
+ raise RetryAgain()
+ return result
+
+ try:
+ result = Retry(helper, delay, timeout, args=args,
+ wait_fn=wait_fn, _time_fn=_time_fn)
+ except RetryTimeout:
+ assert "result" in rdict
+ result = rdict["result"]
+ return result