/
server_streams.go
146 lines (135 loc) · 3.34 KB
/
server_streams.go
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// Copyright © 2017 The Things Network
// Use of this source code is governed by the MIT license that can be found in the LICENSE file.
package broker
import (
"io"
"github.com/TheThingsNetwork/go-utils/log"
"github.com/TheThingsNetwork/ttn/api"
"github.com/TheThingsNetwork/ttn/utils/errors"
"github.com/golang/protobuf/ptypes/empty"
"google.golang.org/grpc/metadata"
)
// BrokerStreamServer handles gRPC streams as channels
type BrokerStreamServer struct {
ctx log.Interface
RouterAssociateChanFunc func(md metadata.MD) (up chan *UplinkMessage, down <-chan *DownlinkMessage, cancel func(), err error)
HandlerSubscribeChanFunc func(md metadata.MD) (ch <-chan *DeduplicatedUplinkMessage, cancel func(), err error)
HandlerPublishChanFunc func(md metadata.MD) (ch chan *DownlinkMessage, err error)
}
// NewBrokerStreamServer returns a new BrokerStreamServer
func NewBrokerStreamServer() *BrokerStreamServer {
return &BrokerStreamServer{
ctx: log.Get(),
}
}
// SetLogger sets the logger
func (s *BrokerStreamServer) SetLogger(logger log.Interface) {
s.ctx = logger
}
// Associate handles uplink streams from and downlink streams to the router
func (s *BrokerStreamServer) Associate(stream Broker_AssociateServer) (err error) {
md, err := api.MetadataFromContext(stream.Context())
if err != nil {
return err
}
upChan, downChan, downCancel, err := s.RouterAssociateChanFunc(md)
if err != nil {
return err
}
defer func() {
ctx := s.ctx
if err != nil {
ctx = ctx.WithError(err)
}
downCancel()
close(upChan)
ctx.Debug("Closed Associate stream")
}()
upErr := make(chan error)
go func() (err error) {
defer func() {
if err != nil {
upErr <- err
}
close(upErr)
}()
for {
uplink, err := stream.Recv()
if err == io.EOF {
return nil
}
if err != nil {
return err
}
if err := uplink.Validate(); err != nil {
return errors.Wrap(err, "Invalid Uplink")
}
upChan <- uplink
}
}()
for {
select {
case err, errPresent := <-upErr:
if !errPresent {
return nil // stream closed
}
return err
case downlink, downlinkPresent := <-downChan:
if !downlinkPresent {
return nil // stream closed
}
if err := stream.Send(downlink); err != nil {
return err
}
}
}
}
// Subscribe handles uplink streams towards the handler
func (s *BrokerStreamServer) Subscribe(req *SubscribeRequest, stream Broker_SubscribeServer) (err error) {
md, err := api.MetadataFromContext(stream.Context())
if err != nil {
return err
}
ch, cancel, err := s.HandlerSubscribeChanFunc(md)
if err != nil {
return err
}
go func() {
<-stream.Context().Done()
err = stream.Context().Err()
cancel()
}()
for uplink := range ch {
if err := stream.Send(uplink); err != nil {
return err
}
}
return
}
// Publish handles downlink streams from the handler
func (s *BrokerStreamServer) Publish(stream Broker_PublishServer) error {
md, err := api.MetadataFromContext(stream.Context())
if err != nil {
return err
}
ch, err := s.HandlerPublishChanFunc(md)
if err != nil {
return err
}
defer func() {
close(ch)
}()
for {
downlink, err := stream.Recv()
if err == io.EOF {
return stream.SendAndClose(&empty.Empty{})
}
if err != nil {
return err
}
if err := downlink.Validate(); err != nil {
return errors.Wrap(err, "Invalid Downlink")
}
ch <- downlink
}
}