This commit allows blocking clients to receive a more informative error
message than "context deadline exceeded", which is especially helpful in
tracking down persistent client misconfiguration (such as an invalid TLS
certificate, an invalid server that's refusing connections, etc.)
Nobody should directly need to reference these packages.
This is technically a breaking change. However:
- Package dns was exporting a NewBuilder method. This should never have been necessary to use, but if so, it can be replaced by importing the "grpc" package and then using resolver.Get("dns").
- Package passthrough was not exporting any symbols and there was never a need to even blank-import it.
After as much searching as possible, it appears nobody in the open source community is referencing either of these packages.
* Implement missing pieces for connection backoff.
Spec can be found here:
https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md
Summary of changes:
* Added a new type (marked experimental), ConnectParams, which contains
the knobs defined in the spec (except for minConnectTimeout).
* Added a new API (marked experimental), WithConnectParams() to return a
DialOption to dial with the provided parameters.
* Added new fields to the implementation of the exponential backoff in
internal/backoff which mirror the ones in ConnectParams.
* Marked existing APIs WithBackoffMaxDelay() and WithBackoffConfig() as
deprecated.
* Added a default exponential backoff implementation, for easy use of
internal callers.
Added a new backoff package which defines the backoff configuration
options, and is used by both the grpc package and the internal/backoff
package. This allows us to have all backoff related options in a
separate package.
Before these fixes, it was possible to see errors on new RPCs after a
connection began draining, and before establishing a new connection. There is
an inherent race between choosing a SubConn and attempting to creating a stream
on it. We should be able to avoid application-visible RPC errors due to this
with transparent retry. However, several bugs were preventing this from
working correctly:
1. Non-wait-for-ready RPCs were skipping transparent retry, though the retry
design calls for retrying them.
2. The transport closed itself (and would consequently error new RPCs) before
notifying the SubConn that it was draining.
3. The SubConn wasn't synchronously updating itself once it was notified about
the closing or draining state.
4. The SubConn would go into the TRANSIENT_FAILURE state instantaneously,
causing RPCs to fail instead of queue.
Easwar Swaminathan
Doug Fawley
Menghan Li
apolcyn
Edmond
Garrett Gutierrez
George Kechagias
Gaurav Gahlot
Sophos
Aliaksandr Mianzhynski
sethp-nr
Patrick Bogen
panguncle
Garrett Gutierrez
Joe Betz
yuxiaobo96