Example: Peer fanout in peer set #3231
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And add a similar method for peer fanouts.
teor2345
commented
Dec 14, 2021
Comment on lines
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| /// Fans out the same request to a few ready peers, | ||
| /// combining successful responses into a single response, | ||
| /// and ignoring errors. | ||
| /// | ||
| /// But if all requests return an error, returns an error from an arbitrary peer. | ||
| fn route_fanout(&mut self, req: Request) -> <Self as tower::Service<Request>>::Future { | ||
| // TODO: does each individual fanout request need a smaller timeout, | ||
| // to avoid stalling all the requests when a single peer doesn't respond? | ||
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| // Limit the fanout to half the ready peers, and to the fanout maximum. | ||
| let half_ready_peers = (self.ready_services.len() + 1) / 2; | ||
| let fanout_peers = min(constants::MAX_REQUEST_FANOUT, half_ready_peers); | ||
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| self.route_multiple(req.clone(), fanout_peers) | ||
| .map(|results| { | ||
| let responses: Vec<Response> = results | ||
| .iter() | ||
| .filter_map(|result| result.as_ref().ok()) | ||
| .cloned() | ||
| .collect(); | ||
| let first_error = results.into_iter().find_map(Result::err); | ||
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| if !responses.is_empty() { | ||
| Ok(combine_fanout_responses(req, responses)) | ||
| } else if let Some(first_error) = first_error { | ||
| // We could return a list of errors, but one should be enough | ||
| Err(first_error) | ||
| } else { | ||
| unreachable!("expected at least one peer result") | ||
| } | ||
| }) | ||
| .boxed() | ||
| } |
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@oxarbitrage this is the code I was struggling to get to compile.
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@oxarbitrage I'm going to close this PR, because we're not going to merge it :-) |
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Motivation
This PR has some example code for ticket #2214.
It should not be merged.