When we receive a FailedPrecondition error, retry that more quickly
because we expect it will resolve shortly. This is particularly
important in the context of Consul servers behind a load balancer
because when establishing a connection we have to retry until we
randomly land on a leader node.
The default retry backoff goes from 2s, 4s, 8s, etc. which can result in
very long delays quite quickly. Instead, this backoff retries in 8ms
five times, then goes exponentially from there: 16ms, 32ms, ... up to a
max of 8152ms.
This mimics xDS's discovery protocol where you must request a resource
explicitly for the exporting side to send those events to you.
As part of this I aligned the overall ResourceURL with the TypeURL that
gets embedded into the encoded protobuf Any construct. The
CheckServiceNodes is now wrapped in a better named "ExportedService"
struct now.
* peerstream: dialer should reconnect when stream closes
If the stream is closed unexpectedly (i.e. when we haven't received
a terminated message), the dialer should attempt to re-establish the
stream.
Previously, the `HandleStream` would return `nil` when the stream
was closed. The caller then assumed the stream was terminated on purpose
and so didn't reconnect when instead it was stopped unexpectedly and
the dialer should have attempted to reconnect.
Previously, public referred to gRPC services that are both exposed on
the dedicated gRPC port and have their definitions in the proto-public
directory (so were considered usable by 3rd parties). Whereas private
referred to services on the multiplexed server port that are only usable
by agents and other servers.
Now, we're splitting these definitions, such that external/internal
refers to the port and public/private refers to whether they can be used
by 3rd parties.
This is necessary because the peering replication API needs to be
exposed on the dedicated port, but is not (yet) suitable for use by 3rd
parties.
Matt Keeler