Retry

Provides generic retry functions.

lib.rs:

Retry is a crate for retrying something that can fail with exponential backoff. It is designed to have a declarative interface for ease of use. It can be used as follows:

# use pravega_client_retry::retry_policy::RetryWithBackoff;
# use pravega_client_retry::retry_result::RetryResult;
# use pravega_client_retry::retry_sync::retry_sync;
# use snafu::Snafu;

    #[derive(Debug, PartialEq, Eq, Snafu)]
    pub enum SnafuError {
        #[snafu(display("Retryable error"))]
        Retryable,
        #[snafu(display("NonRetryable error"))]
        Nonretryable,
    }

let retry_policy = RetryWithBackoff::default_setting().max_tries(1);
let mut collection = vec![1, 2].into_iter();
let value = retry_sync(retry_policy, || match collection.next() {
    Some(n) if n == 2 => RetryResult::Success(n),
    Some(_) => RetryResult::Retry(SnafuError::Retryable),
    None => RetryResult::Fail(SnafuError::Nonretryable),
}).unwrap();

assert_eq!(value, 2);

The above will retry the code 1 times if it throws Err(Retry::Retry). If it throws a Err(Retry::Err) or returns successfully it will return immediately. The delay following each of the filed attempts would be 1, 10,respectively. If all retries fail, it will return Err(RetryErr) that has error message.