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.
1. Call transport Close if newHTTP2Server returns non-nil error.
Handle ConnBegin was called before this error, and handle ConnEnd is not called (because Close() is not called), which caused ConnStats check to fail.
2. Skip stats test in go1.6.
go1.6 doesn't have DialContext (we use Dialer(Cancel: ctx.Done()) instead). When the give context is canceled, this function sometimes returns canceled error, while the server side still gets the conn. This caused the server blocking on reading the preface (which will eventually timeout, but the tests are too short for that), and there will be a missing ConnEnd.
This is in preparation for preventing any user-supplied metadata starting with "grpc-", which is reserved.
* stats: add methods to allow setting grpc-trace-bin and grpc-tags-bin headers
Pick these up in grpc's transport when sending and fill them when receiving.
* Add tags/trace to metadata and tests for that behavior
This is temporary to maintain compatibility and provide a migration strategy.
This will prevent the incoming RPCs' metadata from appearing in outgoing RPCs
unless it is explicitly copied, e.g.:
incomingMD, ok := metadata.FromContext(ctx)
if ok {
ctx = metadata.NewContext(ctx, incomingMD)
}
Fixes#1148
* add stats.tagger APIs and connection stats.
* fix comments
use ac.ctx in http2client
change name and comments
small fixes stats_tests
* add a TODO to ConnTagInfo
* rename handle to handleRPC
* modify stats comments
Brian Tiger Chow
dfawley
Daniel Nephin
Menghan Li
Gyu-Ho Lee
mmukhi
Jan Tattermusch
Charith Ellawala