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.
WithBalancerName dial option specifies the name of the balancer to be used by the ClientConn. Service config updates can NOT override the balancer option.
This allows ClientConn to get more up-to-date addresses from resolver.
ClientConn compares new addresses with the cached ones. So if resolver returns the same set of addresses, ClientConn will not notify balancer about it.
Also moved the initialization of resolver and balancer to avoid race. Balancer will only be started when ClientConn gets resolved addresses from balancer.
- The transport is now responsible for closing its own connection when an error
occurs or when the context given to it in NewClientTransport() is canceled.
- Remove client/server shutdown channels -- add cancel function to allow
self-cancellation.
- Plumb the clientConn's context into the client transport to allow for the
transport to be canceled even after it has been removed from the ac (due to
graceful close) when the ClientConn is closed.
A leak happens when DialContext times out before a balancer returns any
addresses or before a successful connection is established.
The loop in ClientConn.lbWatcher breaks and doneChan never gets closed.
- All logs use 1 severity level instead of printf
- All transport logs only go to verbose level 2+
- The default logger only log errors and verbosity level 1
- Add environment variable GRPC_GO_LOG_SEVERITY_LEVEL and GRPC_GO_LOG_VERBOSITY_LEVEL to set severity or verbosity levels for the default logger
