/
service.go
270 lines (226 loc) · 8.25 KB
/
service.go
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/*
Copyright SecureKey Technologies Inc. All Rights Reserved.
SPDX-License-Identifier: Apache-2.0
*/
package service
import (
"runtime/debug"
"time"
"app/service/fabric-sdk-go-gm/pkg/common/logging"
"app/service/fabric-sdk-go-gm/pkg/common/options"
"app/service/fabric-sdk-go-gm/pkg/common/providers/fab"
"app/service/fabric-sdk-go-gm/pkg/fab/events/service/blockfilter"
"app/service/fabric-sdk-go-gm/pkg/fab/events/service/dispatcher"
"github.com/pkg/errors"
)
const (
// stopTimeout is the time that we wait for the dispatcher to stop.
// It's hard-coded here since (at this point) it doesn't make sense to
// expose it as an option.
stopTimeout = 5 * time.Second
)
var logger = logging.NewLogger("fabsdk/fab")
// EventProducer produces events which are dispatched to clients
type EventProducer interface {
// Register registers the given event channel with the event producer
// and events are sent to this channel.
Register(eventch chan<- interface{})
}
// Dispatcher is responsible for processing registration requests and block/filtered block events.
type Dispatcher interface {
// Start starts the dispatcher, i.e. the dispatcher starts listening for requests/events
Start() error
// EventCh is the event channel over which to communicate with the dispatcher
EventCh() (chan<- interface{}, error)
// LastBlockNum returns the block number of the last block for which an event was received.
LastBlockNum() uint64
}
// Service allows clients to register for channel events, such as filtered block, chaincode, and transaction status events.
type Service struct {
params
dispatcher Dispatcher
}
// New returns a new event service initialized with the given Dispatcher
func New(dispatcher Dispatcher, opts ...options.Opt) *Service {
params := defaultParams()
options.Apply(params, opts)
return &Service{
params: *params,
dispatcher: dispatcher,
}
}
// Start starts the event service
func (s *Service) Start() error {
return s.dispatcher.Start()
}
// Stop stops the event service
func (s *Service) Stop() {
eventch, err := s.dispatcher.EventCh()
if err != nil {
logger.Warnf("Error stopping event service: %s", err)
return
}
errch := make(chan error)
eventch <- dispatcher.NewStopEvent(errch)
select {
case err := <-errch:
if err != nil {
logger.Warnf("Error while stopping dispatcher: %s", err)
}
case <-time.After(stopTimeout):
logger.Infof("Timed out waiting for dispatcher to stop")
}
}
// StopAndTransfer stops the event service and transfers all event registrations into a snapshot.
func (s *Service) StopAndTransfer() (fab.EventSnapshot, error) {
eventch, err := s.dispatcher.EventCh()
if err != nil {
logger.Warnf("Error stopping event service: %s", err)
return nil, err
}
snapshotch := make(chan fab.EventSnapshot)
errch := make(chan error)
eventch <- dispatcher.NewStopAndTransferEvent(snapshotch, errch)
select {
case snapshot := <-snapshotch:
return snapshot, nil
case err := <-errch:
logger.Warnf("Error while stopping dispatcher: %s", err)
return nil, err
case <-time.After(stopTimeout):
logger.Warnf("Timed out waiting for dispatcher to stop")
return nil, errors.New("timed out waiting for dispatcher to stop")
}
}
// Transfer transfers all event registrations into a snapshot.
func (s *Service) Transfer() (fab.EventSnapshot, error) {
eventch, err := s.dispatcher.EventCh()
if err != nil {
logger.Warnf("Error transferring registrations: %s", err)
return nil, err
}
snapshotch := make(chan fab.EventSnapshot)
errch := make(chan error)
eventch <- dispatcher.NewTransferEvent(snapshotch, errch)
select {
case snapshot := <-snapshotch:
return snapshot, nil
case err := <-errch:
logger.Warnf("Error while transferring event registrations into snapshot: %s", err)
return nil, err
case <-time.After(stopTimeout):
logger.Warnf("Timed out waiting to transfer event registrations")
return nil, errors.New("timed out waiting to transfer event registrations")
}
}
// Submit submits an event for processing
func (s *Service) Submit(event interface{}) error {
defer func() {
// During shutdown, events may still be produced and we may
// get a 'send on closed channel' panic. Just log and ignore the error.
if p := recover(); p != nil {
logger.Warnf("panic while submitting event: %s", p)
debug.PrintStack()
}
}()
eventch, err := s.dispatcher.EventCh()
if err != nil {
return errors.WithMessage(err, "Error submitting to event dispatcher")
}
eventch <- event
return nil
}
// Dispatcher returns the event dispatcher
func (s *Service) Dispatcher() Dispatcher {
return s.dispatcher
}
// RegisterBlockEvent registers for block events. If the client is not authorized to receive
// block events then an error is returned.
func (s *Service) RegisterBlockEvent(filter ...fab.BlockFilter) (fab.Registration, <-chan *fab.BlockEvent, error) {
eventch := make(chan *fab.BlockEvent, s.eventConsumerBufferSize)
regch := make(chan fab.Registration)
errch := make(chan error)
blockFilter := blockfilter.AcceptAny
if len(filter) > 1 {
return nil, nil, errors.New("only one block filter may be specified")
}
if len(filter) == 1 {
blockFilter = filter[0]
}
if err := s.Submit(dispatcher.NewRegisterBlockEvent(blockFilter, eventch, regch, errch)); err != nil {
return nil, nil, errors.WithMessage(err, "error registering for block events")
}
select {
case response := <-regch:
return response, eventch, nil
case err := <-errch:
return nil, nil, err
}
}
// RegisterFilteredBlockEvent registers for filtered block events. If the client is not authorized to receive
// filtered block events then an error is returned.
func (s *Service) RegisterFilteredBlockEvent() (fab.Registration, <-chan *fab.FilteredBlockEvent, error) {
eventch := make(chan *fab.FilteredBlockEvent, s.eventConsumerBufferSize)
regch := make(chan fab.Registration)
errch := make(chan error)
if err := s.Submit(dispatcher.NewRegisterFilteredBlockEvent(eventch, regch, errch)); err != nil {
return nil, nil, errors.WithMessage(err, "error registering for filtered block events")
}
select {
case response := <-regch:
return response, eventch, nil
case err := <-errch:
return nil, nil, err
}
}
// RegisterChaincodeEvent registers for chaincode events. If the client is not authorized to receive
// chaincode events then an error is returned.
// - ccID is the chaincode ID for which events are to be received
// - eventFilter is the chaincode event name for which events are to be received
func (s *Service) RegisterChaincodeEvent(ccID, eventFilter string) (fab.Registration, <-chan *fab.CCEvent, error) {
if ccID == "" {
return nil, nil, errors.New("chaincode ID is required")
}
if eventFilter == "" {
return nil, nil, errors.New("event filter is required")
}
eventch := make(chan *fab.CCEvent, s.eventConsumerBufferSize)
regch := make(chan fab.Registration)
errch := make(chan error)
if err := s.Submit(dispatcher.NewRegisterChaincodeEvent(ccID, eventFilter, eventch, regch, errch)); err != nil {
return nil, nil, errors.WithMessage(err, "error registering for chaincode events")
}
select {
case response := <-regch:
return response, eventch, nil
case err := <-errch:
return nil, nil, err
}
}
// RegisterTxStatusEvent registers for transaction status events. If the client is not authorized to receive
// transaction status events then an error is returned.
// - txID is the transaction ID for which events are to be received
func (s *Service) RegisterTxStatusEvent(txID string) (fab.Registration, <-chan *fab.TxStatusEvent, error) {
if txID == "" {
return nil, nil, errors.New("txID must be provided")
}
eventch := make(chan *fab.TxStatusEvent, s.eventConsumerBufferSize)
regch := make(chan fab.Registration)
errch := make(chan error)
if err := s.Submit(dispatcher.NewRegisterTxStatusEvent(txID, eventch, regch, errch)); err != nil {
return nil, nil, errors.WithMessage(err, "error registering for Tx Status events")
}
select {
case response := <-regch:
return response, eventch, nil
case err := <-errch:
return nil, nil, err
}
}
// Unregister unregisters the given registration.
// - reg is the registration handle that was returned from one of the RegisterXXX functions
func (s *Service) Unregister(reg fab.Registration) {
if err := s.Submit(dispatcher.NewUnregisterEvent(reg)); err != nil {
logger.Warnf("Error unregistering: %s", err)
}
}