// NewClientStream creates a new Stream for the client side. This is called
// by generated code.
func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
var (
conn *Conn
t transport.ClientTransport
err error
)
for {
conn, err = cc.dopts.picker.Pick()
if err != nil {
return nil, toRPCErr(err)
}
t, err = conn.Wait(ctx)
if err != nil {
if err == ErrTransientFailure {
continue
}
return nil, toRPCErr(err)
}
break
}
// TODO(zhaoq): CallOption is omitted. Add support when it is needed.
callHdr := &transport.CallHdr{
Host: conn.authority,
Method: method,
}
cs := &clientStream{
desc: desc,
codec: conn.dopts.codec,
tracing: EnableTracing,
}
if cs.tracing {
cs.traceInfo.tr = trace.New("grpc.Sent."+transport.MethodFamily(method), method)
cs.traceInfo.firstLine.client = true
if deadline, ok := ctx.Deadline(); ok {
cs.traceInfo.firstLine.deadline = deadline.Sub(time.Now())
}
cs.traceInfo.tr.LazyLog(&cs.traceInfo.firstLine, false)
ctx = trace.NewContext(ctx, cs.traceInfo.tr)
}
s, err := t.NewStream(ctx, callHdr)
if err != nil {
return nil, toRPCErr(err)
}
cs.t = t
cs.s = s
cs.p = &parser{s: s}
return cs, nil
}
// Invoke is called by the generated code. It sends the RPC request on the
// wire and returns after response is received.
func Invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (err error) {
var c callInfo
for _, o := range opts {
if err := o.before(&c); err != nil {
return toRPCErr(err)
}
}
defer func() {
for _, o := range opts {
o.after(&c)
}
}()
if EnableTracing {
c.traceInfo.tr = trace.New("grpc.Sent."+transport.MethodFamily(method), method)
defer c.traceInfo.tr.Finish()
c.traceInfo.firstLine.client = true
if deadline, ok := ctx.Deadline(); ok {
c.traceInfo.firstLine.deadline = deadline.Sub(time.Now())
}
c.traceInfo.tr.LazyLog(&c.traceInfo.firstLine, false)
// TODO(dsymonds): Arrange for c.traceInfo.firstLine.remoteAddr to be set.
defer func() {
if err != nil {
c.traceInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
c.traceInfo.tr.SetError()
}
}()
}
topts := &transport.Options{
Last: true,
Delay: false,
}
var (
lastErr error // record the error that happened
)
for {
var (
err error
t transport.ClientTransport
stream *transport.Stream
conn *Conn
)
// TODO(zhaoq): Need a formal spec of retry strategy for non-failfast rpcs.
if lastErr != nil && c.failFast {
return toRPCErr(lastErr)
}
conn, err = cc.dopts.picker.Pick()
if err != nil {
return toRPCErr(err)
}
callHdr := &transport.CallHdr{
Host: conn.authority,
Method: method,
}
t, err = conn.Wait(ctx)
if err != nil {
if err == ErrTransientFailure {
continue
}
if lastErr != nil {
// This was a retry; return the error from the last attempt.
return toRPCErr(lastErr)
}
return toRPCErr(err)
}
if c.traceInfo.tr != nil {
c.traceInfo.tr.LazyLog(&payload{sent: true, msg: args}, true)
}
stream, err = sendRequest(ctx, conn.dopts.codec, callHdr, t, args, topts)
if err != nil {
if _, ok := err.(transport.ConnectionError); ok {
lastErr = err
continue
}
if lastErr != nil {
return toRPCErr(lastErr)
}
return toRPCErr(err)
}
// Receive the response
lastErr = recvResponse(conn.dopts.codec, t, &c, stream, reply)
if _, ok := lastErr.(transport.ConnectionError); ok {
continue
}
if c.traceInfo.tr != nil {
c.traceInfo.tr.LazyLog(&payload{sent: false, msg: reply}, true)
}
t.CloseStream(stream, lastErr)
if lastErr != nil {
return toRPCErr(lastErr)
}
return Errorf(stream.StatusCode(), stream.StatusDesc())
}
}