RetryPolicy
Related Docs:
object RetryPolicy
| package service
Creates a new RetryPolicy based on the current RetryPolicy in which values of A
are first checked against a predicate function, and only if the predicate returns true
will the value be passed on to the current RetryPolicy.
Creates a new RetryPolicy based on the current RetryPolicy in which values of A
are first checked against a predicate function, and only if the predicate returns true
will the value be passed on to the current RetryPolicy.
The predicate function need not be a pure function, but can change its behavior over
time. For example, the predicate function's decision can be based upon backpressure
signals supplied by things like failure rates or latency, which allows RetryPolicys
to dynamically reduce the number of retries in response to backpressure.
The predicate function is only called on the first failure in a chain. Any additional
chained RetryPolicies returned by the current policy will then see additional failures
unfiltered. Contrast this will filterEach, which applies the filter to each RetryPolicy
in the chain.
Similar to filter, but the predicate is applied to each RetryPolicy in the chain
returned by the current RetryPolicy.
Similar to filter, but the predicate is applied to each RetryPolicy in the chain
returned by the current RetryPolicy. For example, if the current RetryPolicy returns
Some((D, P')) for value E (of type A), and the given predicate returns true for E,
then the value returned from the filtering RetryPolicy will be Some((D, P)) where
P is equal to P'.filterEach(pred).
One example where this is useful is to dynamically and fractionally allow retries based
upon backpressure signals. If, for example, the predicate function returned true or false
based upon a probability distribution computed from a backpressure signal, it could return
true 50% of the time, giving you a 50% chance of performing a single retry, a 25% chance of
performing 2 retries, 12.5% chance of performing 3 retries, etc. This might be more
desirable than just using filter where you end up with a 50% chance of no retries and
50% chance of the full number of retries.
Applies a dynamically chosen retry limit to an existing RetryPolicy that may allow for
more retries.
Applies a dynamically chosen retry limit to an existing RetryPolicy that may allow for
more retries. When the returned RetryPolicy is first invoked, it will call the maxRetries
by-name parameter to get the current maximum retries allowed. Regardless of the number
of retries that the underlying policy would allow, it is capped to be no greater than the
number returned by maxRetries on the first failure in the chain.
Using a dynamically choosen retry limit allows for the retry count to be tuned at runtime based upon backpressure signals such as failure rate or request latency.
A function defining retry behavior for a given value type
A.