- Provide AppendToOutgoingContext interface for imrproved performance
over manually creating md and joining with existing md
- Add benchmarks for old/new approaches
Fixes#1390
This change introduces some behavior changes that should not impact users that
are following the proper stream protocol. Specifically, one of the following
conditions must be satisfied:
1. The user calls Close on the ClientConn.
2. The user cancels the context provided to NewClientStream, or its deadline
expires. (Note that it if the context is no longer needed before the deadline
expires, it is still recommended to call cancel to prevent bloat.) It is always
recommended to cancel contexts when they are no longer needed, and to
never use the background context directly, so all users should always be
doing this.
3. The user calls RecvMsg (or Recv in generated code) until a non-nil error is
returned.
4. The user receives any error from Header or SendMsg (or Send in generated
code) besides io.EOF. If none of the above happen, this will leak a goroutine
and a context, and grpc will not call the optionally-configured stats handler
with a stats.End message.
Before this change, if a user created a stream and the server ended the stream,
the stats handler would be invoked with a stats.End containing the final status
of the stream. Subsequent calls to RecvMsg would then trigger the stats handler
with InPayloads, which may be unexpected by stats handlers.
New connections can race with GracefulStop such that the server will accept the connection, but then close it immediately. If a connection is accepted before GracefulStop has a chance to effectively cancel the listeners, the server should handle it to avoid client errors.
The parent ClientConn should re-resolve when grpclb loses connection to the
remote balancer.
When the ClientConn inside grpclb gets a TransientFailure, it calls
lbManualResolver.ResolveNow(), which calls parent ClientConn's ResolveNow, and
eventually results in re-resolve happening in parent ClientConn's resolver (DNS
for example).
This PR adds a method to balancer.ClientConn interface, so balancer can tell
parent ClientConn to re-resolve.
WithBalancerName dial option specifies the name of the balancer to be used by the ClientConn. Service config updates can NOT override the balancer option.
