fix(transport): return Poll::ready until error is consumed #495
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
When a lazy connection fails to connect it first returns Poll::ready from the reconnect service, yet the subsequent call returns Poll::pending making tower_balance loop forever. Instead, on error we return Ready until the error is consumed in the call method.
LucioFranco
requested changes
Jan 5, 2021
Member
LucioFranco
left a comment
LucioFranco
left a comment
There was a problem hiding this comment.
Sorry for the delay on this! I'd like to see that one trait bound change, then we can merge it.
| pub(crate) struct Reconnect<M, Target> | ||
| where | ||
| M: Service<Target>, | ||
| M::Error: Debug, |
Member
There was a problem hiding this comment.
I think we actually want to use Into<Box<dyn Error + Send + Sync>> here and then convert it. If it impls that trait and you call into() then it will automatically impl Debug because of the Error trait.
Contributor
Author
There was a problem hiding this comment.
I think I've done what you've suggested in the last comment.
LucioFranco
reviewed
Jan 14, 2021
| M::Future: Unpin, | ||
| Error: From<M::Error> + From<S::Error>, | ||
| Target: Clone, | ||
| <M as tower_service::Service<Target>>::Error: fmt::Debug, |
Member
There was a problem hiding this comment.
This still needs to be Into<Error> or else it might break the stack down the line.
Member
|
Closing in favor of #536 |
Member
|
Thanks @tl-helge-hoff for getting this started! |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When a lazy connection fails to connect the first time it returns Poll::ready and saves the error in the Reconnect service.
Subsequent calls to
Reconnect::poll_readyreturnPoll::Pendingwhich makes tower_balance loop forever as it will never get a ready service.This is due to
Reconnect::poll_readybeing called twice bytower_balanceand returning firstPoll::Readyand thenPoll::Pending.Motivation
We bumped into the infinite-looping issue while using the
Channel::balance_channeltogether with tls,when our tls config was incorrect and triggering an error during the handshake.
Solution
Reconnect::poll_readywill consistently returnPoll::Readyuntil the error is consumed inReconnect::call.After the error is consumed, and the error is surfaced through a client call, the
Reconnectservice will try to connect again.The PR also adds trace logging in the
Reconnectservice.