/
stream.go
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/
stream.go
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//
// Copyright (C) 2019-2020 Vdaas.org Vald team ( kpango, rinx, kmrmt )
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Package grpc provides generic functionality for grpc
package grpc
import (
"context"
"io"
"runtime"
"github.com/vdaas/vald/internal/errgroup"
"github.com/vdaas/vald/internal/errors"
"github.com/vdaas/vald/internal/log"
"github.com/vdaas/vald/internal/safety"
"google.golang.org/grpc"
)
type ClientStream = grpc.ClientStream
// BidirectionalStream represents gRPC bidirectional stream server handler.
func BidirectionalStream(ctx context.Context, stream grpc.ServerStream,
concurrency int,
newData func() interface{},
f func(context.Context, interface{}) (interface{}, error)) (err error) {
eg, ctx := errgroup.New(ctx)
if concurrency > 0 {
eg.Limitation(concurrency)
}
for {
select {
case <-ctx.Done():
err = eg.Wait()
if err != nil {
log.Error(err)
return err
}
return nil
default:
data := newData()
err = stream.RecvMsg(data)
if err != nil {
if err == io.EOF {
err = eg.Wait()
if err != nil {
log.Error(err)
return err
}
return nil
}
log.Error(err)
return err
}
if data != nil {
eg.Go(safety.RecoverFunc(func() (err error) {
var res interface{}
res, err = f(ctx, data)
if err != nil {
runtime.Gosched()
return err
}
if res != nil {
err = stream.SendMsg(res)
if err != nil {
runtime.Gosched()
return err
}
}
return nil
}))
}
}
}
}
// BidirectionalStreamClient is gRPC client stream.
func BidirectionalStreamClient(stream grpc.ClientStream,
dataProvider func() interface{},
newData func() interface{},
f func(interface{}, error)) (err error) {
ctx, cancel := context.WithCancel(stream.Context())
eg, ctx := errgroup.New(ctx)
eg.Go(safety.RecoverFunc(func() (err error) {
for {
select {
case <-ctx.Done():
return ctx.Err()
default:
res := newData()
err = stream.RecvMsg(res)
if err == io.EOF {
cancel()
return nil
}
f(res, err)
}
}
}))
defer func() {
if err != nil {
err = errors.Wrap(stream.CloseSend(), err.Error())
} else {
err = stream.CloseSend()
}
}()
return func() (err error) {
for {
select {
case <-ctx.Done():
return eg.Wait()
default:
data := dataProvider()
if data == nil {
err = stream.CloseSend()
cancel()
if err != nil {
return errors.Wrap(eg.Wait(), err.Error())
}
return eg.Wait()
}
err = stream.SendMsg(data)
if err != nil {
return err
}
}
}
}()
}