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// Copyright (c) 2017 Cisco and/or its affiliates.
//
// 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:
//
// http://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 core
import (
"fmt"
"git.fd.io/govpp.git/api"
logger "github.com/sirupsen/logrus"
)
// processSubscriptionRequest processes a notification subscribe request.
func (c *Connection) processSubscriptionRequest(ch *channel, req *subscriptionRequest) error {
var err error
// subscribe / unsubscribe
if req.subscribe {
err = c.addNotifSubscription(req.sub)
} else {
err = c.removeNotifSubscription(req.sub)
}
// send the reply into the go channel
select {
case ch.notifSubsReplyChan <- err:
// reply sent successfully
default:
// unable to write into the channel without blocking
log.WithFields(logger.Fields{
"channel": ch.id,
}).Warn("Unable to deliver the subscribe reply, reciever end not ready.")
}
return err
}
// addNotifSubscription adds the notification subscription into the subscriptions map of the connection.
func (c *Connection) addNotifSubscription(subs *api.NotifSubscription) error {
// get message ID of the notification message
msgID, msgName, err := c.getSubscriptionMessageID(subs)
if err != nil {
return err
}
log.WithFields(logger.Fields{
"msg_name": msgName,
"msg_id": msgID,
}).Debug("Adding new notification subscription.")
// add the subscription into map
c.notifSubscriptionsLock.Lock()
defer c.notifSubscriptionsLock.Unlock()
c.notifSubscriptions[msgID] = append(c.notifSubscriptions[msgID], subs)
return nil
}
// removeNotifSubscription removes the notification subscription from the subscriptions map of the connection.
func (c *Connection) removeNotifSubscription(subs *api.NotifSubscription) error {
// get message ID of the notification message
msgID, msgName, err := c.getSubscriptionMessageID(subs)
if err != nil {
return err
}
log.WithFields(logger.Fields{
"msg_name": msgName,
"msg_id": msgID,
}).Debug("Removing notification subscription.")
// remove the subscription from the map
c.notifSubscriptionsLock.Lock()
defer c.notifSubscriptionsLock.Unlock()
for i, item := range c.notifSubscriptions[msgID] {
if item == subs {
// remove i-th item in the slice
c.notifSubscriptions[msgID] = append(c.notifSubscriptions[msgID][:i], c.notifSubscriptions[msgID][i+1:]...)
break
}
}
return nil
}
// isNotificationMessage returns true if someone has subscribed to provided message ID.
func (c *Connection) isNotificationMessage(msgID uint16) bool {
c.notifSubscriptionsLock.RLock()
defer c.notifSubscriptionsLock.RUnlock()
_, exists := c.notifSubscriptions[msgID]
return exists
}
// sendNotifications send a notification message to all subscribers subscribed for that message.
func (c *Connection) sendNotifications(msgID uint16, data []byte) {
c.notifSubscriptionsLock.RLock()
defer c.notifSubscriptionsLock.RUnlock()
matched := false
// send to notification to each subscriber
for _, subs := range c.notifSubscriptions[msgID] {
msg := subs.MsgFactory()
log.WithFields(logger.Fields{
"msg_name": msg.GetMessageName(),
"msg_id": msgID,
"msg_size": len(data),
}).Debug("Sending a notification to the subscription channel.")
if err := c.codec.DecodeMsg(data, msg); err != nil {
log.WithFields(logger.Fields{
"msg_name": msg.GetMessageName(),
"msg_id": msgID,
"msg_size": len(data),
}).Errorf("Unable to decode the notification message: %v", err)
continue
}
// send the message into the go channel of the subscription
select {
case subs.NotifChan <- msg:
// message sent successfully
default:
// unable to write into the channel without blocking
log.WithFields(logger.Fields{
"msg_name": msg.GetMessageName(),
"msg_id": msgID,
"msg_size": len(data),
}).Warn("Unable to deliver the notification, reciever end not ready.")
}
matched = true
}
if !matched {
log.WithFields(logger.Fields{
"msg_id": msgID,
"msg_size": len(data),
}).Info("No subscription found for the notification message.")
}
}
// getSubscriptionMessageID returns ID of the message the subscription is tied to.
func (c *Connection) getSubscriptionMessageID(subs *api.NotifSubscription) (uint16, string, error) {
msg := subs.MsgFactory()
msgID, err := c.GetMessageID(msg)
if err != nil {
log.WithFields(logger.Fields{
"msg_name": msg.GetMessageName(),
"msg_crc": msg.GetCrcString(),
}).Errorf("unable to retrieve message ID: %v", err)
return 0, "", fmt.Errorf("unable to retrieve message ID: %v", err)
}
return msgID, msg.GetMessageName(), nil
}
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