[−][src]Crate again
Again is a wasm-compatible utility for retrying standard library Futures with a Result output type
A goal of any operation should be a successful outcome. This crate gives operations a better chance at achieving that.
Examples
Hello world
For simple cases, you can use the module level retry fn, which
will retry a task every second for 5 seconds with an exponential backoff.
again::retry(|| reqwest::get("https://api.company.com"));
Conditional retries
By default, again will retry any failed Future if its Result output type is an Err.
You may not want to retry every kind of error. In those cases you may wish to use the retry_if fn, which
accepts an additional argument to conditionally determine if the error
should be retried.
again::retry_if( || reqwest::get("https://api.company.com"), reqwest::Error::is_status, );
Retry policies
Every application has different needs. The default retry behavior in again
likely will not suit all of them. You can define your own retry behavior
with a RetryPolicy. A RetryPolicy can be configured with a fixed or exponential backoff,
jitter, and other common retry options. This objects may be reused
across operations. For more information see the RetryPolicy docs.
use again::RetryPolicy; use std::time::Duration; let policy = RetryPolicy::fixed(Duration::from_millis(100)) .with_max_retries(10) .with_jitter(false); policy.retry(|| reqwest::get("https://api.company.com"));
Logging
For visibility on when operations fail and are retried, a log::trace message is emitted,
logging the Debug display of the error and the delay before the next attempt.
wasm features
again supports WebAssembly targets i.e. wasm32-unknown-unknown which should make this
crate a good fit for most environments
Two cargo features exist to support various wasm runtimes: wasm-bindgen and stdweb.
To enable them add the following to your Cargo.toml file.
[dependencies]
again = { version = "xxx", features = ["wasm-bindgen"] }
Structs
| RetryPolicy | A template for configuring retry behavior |
Traits
| Condition | A type to determine if a failed Future should be retried |
| Task | A unit of work to be retried |
Functions
| retry | Retries a fallible |
| retry_if | Retries a fallible |