57 lines
2.0 KiB
Rust
57 lines
2.0 KiB
Rust
use std::pin::Pin;
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use futures::{Future, FutureExt};
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use tower::retry::Policy;
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/// A very basic retry policy with a limited number of retry attempts.
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///
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/// TODO: Remove this when <https://github.com/tower-rs/tower/pull/414> lands.
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#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
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pub struct RetryLimit {
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remaining_tries: usize,
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}
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impl RetryLimit {
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/// Create a policy with the given number of retry attempts.
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pub fn new(retry_attempts: usize) -> Self {
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RetryLimit {
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remaining_tries: retry_attempts,
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}
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}
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}
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impl<Req: Clone + std::fmt::Debug, Res, E: std::fmt::Debug> Policy<Req, Res, E> for RetryLimit {
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type Future = Pin<Box<dyn Future<Output = Self> + Send + Sync + 'static>>;
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fn retry(&self, req: &Req, result: Result<&Res, &E>) -> Option<Self::Future> {
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if let Err(e) = result {
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if self.remaining_tries > 0 {
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tracing::debug!(?req, ?e, remaining_tries = self.remaining_tries, "retrying");
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let remaining_tries = self.remaining_tries - 1;
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let retry_outcome = RetryLimit { remaining_tries };
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Some(
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// Let other tasks run, so we're more likely to choose a different peer,
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// and so that any notfound inv entries win the race to the PeerSet.
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//
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// # Security
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//
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// We want to choose different peers for retries, so we have a better chance of getting each block.
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// This is implemented by the connection state machine sending synthetic `notfound`s to the
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// `InventoryRegistry`, as well as forwarding actual `notfound`s from peers.
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Box::pin(tokio::task::yield_now().map(move |()| retry_outcome)),
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)
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} else {
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None
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}
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} else {
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None
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}
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}
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fn clone_request(&self, req: &Req) -> Option<Req> {
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Some(req.clone())
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}
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}
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