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eventserviceref.go
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eventserviceref.go
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/*
Copyright SecureKey Technologies Inc. All Rights Reserved.
SPDX-License-Identifier: Apache-2.0
*/
package chpvdr
import (
"sync/atomic"
"time"
"github.com/pkg/errors"
"github.com/vtbaas/vbaas-go-sdk/pkg/common/providers/fab"
"github.com/vtbaas/vbaas-go-sdk/pkg/util/concurrent/lazyref"
)
const (
defaultTimeout = 60 * time.Second
)
type eventClientProvider func() (fab.EventClient, error)
// EventClientRef holds a reference to the event client and manages its lifecycle.
// When the idle timeout has been reached then the event client is closed. The next time
// the event client ref is accessed, a new event client is created.
// The EventClientRef implements all of the functions of fab.EventService, so the
// EventClientRef may be used wherever an EventService is required.
type EventClientRef struct {
ref *lazyref.Reference
provider eventClientProvider
eventClient fab.EventClient
closed int32
}
// NewEventClientRef returns a new EventClientRef
func NewEventClientRef(idleTimeout time.Duration, evtClientProvider eventClientProvider) *EventClientRef {
clientRef := &EventClientRef{
provider: evtClientProvider,
}
if idleTimeout == 0 {
idleTimeout = defaultTimeout
}
clientRef.ref = lazyref.New(
clientRef.initializer(),
lazyref.WithFinalizer(clientRef.finalizer()),
lazyref.WithIdleExpiration(idleTimeout),
)
return clientRef
}
// Close immediately closes the connection.
func (ref *EventClientRef) Close() {
if !atomic.CompareAndSwapInt32(&ref.closed, 0, 1) {
// Already closed
return
}
logger.Debug("Closing the event client")
ref.ref.Close()
}
// Closed returns true if the event client is closed
func (ref *EventClientRef) Closed() bool {
return atomic.LoadInt32(&ref.closed) == 1
}
// RegisterBlockEvent registers for block events.
func (ref *EventClientRef) RegisterBlockEvent(filter ...fab.BlockFilter) (fab.Registration, <-chan *fab.BlockEvent, error) {
service, err := ref.get()
if err != nil {
return nil, nil, err
}
return service.RegisterBlockEvent(filter...)
}
// RegisterFilteredBlockEvent registers for filtered block events.
func (ref *EventClientRef) RegisterFilteredBlockEvent() (fab.Registration, <-chan *fab.FilteredBlockEvent, error) {
service, err := ref.get()
if err != nil {
return nil, nil, err
}
return service.RegisterFilteredBlockEvent()
}
// RegisterChaincodeEvent registers for chaincode events.
func (ref *EventClientRef) RegisterChaincodeEvent(ccID, eventFilter string) (fab.Registration, <-chan *fab.CCEvent, error) {
service, err := ref.get()
if err != nil {
return nil, nil, err
}
return service.RegisterChaincodeEvent(ccID, eventFilter)
}
// RegisterTxStatusEvent registers for transaction status events.
func (ref *EventClientRef) RegisterTxStatusEvent(txID string) (fab.Registration, <-chan *fab.TxStatusEvent, error) {
service, err := ref.get()
if err != nil {
return nil, nil, err
}
return service.RegisterTxStatusEvent(txID)
}
// Unregister removes the given registration and closes the event channel.
func (ref *EventClientRef) Unregister(reg fab.Registration) {
if service, err := ref.get(); err != nil {
logger.Warnf("Error unregistering event registration: %s", err)
} else {
service.Unregister(reg)
}
}
func (ref *EventClientRef) get() (fab.EventService, error) {
if ref.Closed() {
return nil, errors.New("event client is closed")
}
service, err := ref.ref.Get()
if err != nil {
return nil, err
}
return service.(fab.EventService), nil
}
func (ref *EventClientRef) initializer() lazyref.Initializer {
return func() (interface{}, error) {
if ref.eventClient != nil {
// Already connected
return ref.eventClient, nil
}
logger.Debug("Creating event client...")
eventClient, err := ref.provider()
if err != nil {
return nil, err
}
logger.Debug("...connecting event client...")
if err := eventClient.Connect(); err != nil {
return nil, err
}
ref.eventClient = eventClient
logger.Debug("...event client successfully connected.")
return eventClient, nil
}
}
func (ref *EventClientRef) finalizer() lazyref.Finalizer {
return func(interface{}) {
logger.Debug("Finalizer called")
if ref.eventClient != nil {
if ref.Closed() {
logger.Debug("Forcing close the event client")
ref.eventClient.Close()
} else {
logger.Debug("Closing the event client if no outstanding connections...")
// Only close the client if there are not outstanding registrations
if ref.eventClient.CloseIfIdle() {
logger.Debug("... closed event client.")
ref.eventClient = nil
} else {
logger.Debug("... event client was not closed since there are outstanding registrations.")
}
}
}
}
}