1 // Copyright (c) 2017 Cisco and/or its affiliates.
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at:
7 // http://www.apache.org/licenses/LICENSE-2.0
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
22 "github.com/sirupsen/logrus"
25 // MessageType represents the type of a VPP message.
29 // RequestMessage represents a VPP request message
30 RequestMessage MessageType = iota
31 // ReplyMessage represents a VPP reply message
33 // EventMessage represents a VPP notification event message
35 // OtherMessage represents other VPP message (e.g. counters)
39 // Message is an interface that is implemented by all VPP Binary API messages generated by the binapigenerator.
40 type Message interface {
41 // GetMessageName returns the original VPP name of the message, as defined in the VPP API.
42 GetMessageName() string
44 // GetMessageType returns the type of the VPP message.
45 GetMessageType() MessageType
47 // GetCrcString returns the string with CRC checksum of the message definition (the string represents a hexadecimal number).
51 // DataType is an interface that is implemented by all VPP Binary API data types by the binapi_generator.
52 type DataType interface {
53 // GetTypeName returns the original VPP name of the data type, as defined in the VPP API.
56 // GetCrcString returns the string with CRC checksum of the data type definition (the string represents a hexadecimal number).
60 // ChannelProvider provides the communication channel with govpp core.
61 type ChannelProvider interface {
62 // NewAPIChannel returns a new channel for communication with VPP via govpp core.
63 // It uses default buffer sizes for the request and reply Go channels.
64 NewAPIChannel() (*Channel, error)
66 // NewAPIChannelBuffered returns a new channel for communication with VPP via govpp core.
67 // It allows to specify custom buffer sizes for the request and reply Go channels.
68 NewAPIChannelBuffered() (*Channel, error)
71 // MessageDecoder provides functionality for decoding binary data to generated API messages.
72 type MessageDecoder interface {
73 // DecodeMsg decodes binary-encoded data of a message into provided Message structure.
74 DecodeMsg(data []byte, msg Message) error
77 // MessageIdentifier provides identification of generated API messages.
78 type MessageIdentifier interface {
79 // GetMessageID returns message identifier of given API message.
80 GetMessageID(msg Message) (uint16, error)
83 // Channel is the main communication interface with govpp core. It contains two Go channels, one for sending the requests
84 // to VPP and one for receiving the replies from it. The user can access the Go channels directly, or use the helper
85 // methods provided inside of this package. Do not use the same channel from multiple goroutines concurrently,
86 // otherwise the responses could mix! Use multiple channels instead.
88 ReqChan chan *VppRequest // channel for sending the requests to VPP, closing this channel releases all resources in the ChannelProvider
89 ReplyChan chan *VppReply // channel where VPP replies are delivered to
91 NotifSubsChan chan *NotifSubscribeRequest // channel for sending notification subscribe requests
92 NotifSubsReplyChan chan error // channel where replies to notification subscribe requests are delivered to
94 MsgDecoder MessageDecoder // used to decode binary data to generated API messages
95 MsgIdentifier MessageIdentifier // used to retrieve message ID of a message
97 replyTimeout time.Duration // maximum time that the API waits for a reply from VPP before returning an error, can be set with SetReplyTimeout
98 metadata interface{} // opaque metadata of the API channel
99 lastTimedOut bool // wether last request timed out
102 // VppRequest is a request that will be sent to VPP.
103 type VppRequest struct {
104 Message Message // binary API message to be send to VPP
105 Multipart bool // true if multipart response is expected, false otherwise
108 // VppReply is a reply received from VPP.
109 type VppReply struct {
110 MessageID uint16 // ID of the message
111 Data []byte // encoded data with the message - MessageDecoder can be used for decoding
112 LastReplyReceived bool // in case of multipart replies, true if the last reply has been already received and this one should be ignored
113 Error error // in case of error, data is nil and this member contains error description
116 // NotifSubscribeRequest is a request to subscribe for delivery of specific notification messages.
117 type NotifSubscribeRequest struct {
118 Subscription *NotifSubscription // subscription details
119 Subscribe bool // true if this is a request to subscribe, false if unsubscribe
122 // NotifSubscription represents a subscription for delivery of specific notification messages.
123 type NotifSubscription struct {
124 NotifChan chan Message // channel where notification messages will be delivered to
125 MsgFactory func() Message // function that returns a new instance of the specific message that is expected as a notification
128 // RequestCtx is a context of a ongoing request (simple one - only one response is expected).
129 type RequestCtx struct {
133 // MultiRequestCtx is a context of a ongoing multipart request (multiple responses are expected).
134 type MultiRequestCtx struct {
138 const defaultReplyTimeout = time.Second * 1 // default timeout for replies from VPP, can be changed with SetReplyTimeout
140 // NewChannelInternal returns a new channel structure with metadata field filled in with the provided argument.
141 // Note that this is just a raw channel not yet connected to VPP, it is not intended to be used directly.
142 // Use ChannelProvider to get an API channel ready for communication with VPP.
143 func NewChannelInternal(metadata interface{}) *Channel {
145 replyTimeout: defaultReplyTimeout,
150 // Metadata returns the metadata stored within the channel structure by the NewChannelInternal call.
151 func (ch *Channel) Metadata() interface{} {
155 // SetReplyTimeout sets the timeout for replies from VPP. It represents the maximum time the API waits for a reply
156 // from VPP before returning an error.
157 func (ch *Channel) SetReplyTimeout(timeout time.Duration) {
158 ch.replyTimeout = timeout
161 // Close closes the API channel and releases all API channel-related resources in the ChannelProvider.
162 func (ch *Channel) Close() {
163 if ch.ReqChan != nil {
168 // SendRequest asynchronously sends a request to VPP. Returns a request context, that can be used to call ReceiveReply.
169 // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply).
170 func (ch *Channel) SendRequest(msg Message) *RequestCtx {
171 ch.ReqChan <- &VppRequest{
174 return &RequestCtx{ch: ch}
177 // ReceiveReply receives a reply from VPP (blocks until a reply is delivered from VPP, or until an error occurs).
178 // The reply will be decoded into the msg argument. Error will be returned if the response cannot be received or decoded.
179 func (req *RequestCtx) ReceiveReply(msg Message) error {
180 if req == nil || req.ch == nil {
181 return errors.New("invalid request context")
184 lastReplyReceived, err := req.ch.receiveReplyInternal(msg)
186 if lastReplyReceived {
187 err = errors.New("multipart reply recieved while a simple reply expected")
192 // SendMultiRequest asynchronously sends a multipart request (request to which multiple responses are expected) to VPP.
193 // Returns a multipart request context, that can be used to call ReceiveReply.
194 // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply).
195 func (ch *Channel) SendMultiRequest(msg Message) *MultiRequestCtx {
196 ch.ReqChan <- &VppRequest{
200 return &MultiRequestCtx{ch: ch}
203 // ReceiveReply receives a reply from VPP (blocks until a reply is delivered from VPP, or until an error occurs).
204 // The reply will be decoded into the msg argument. If the last reply has been already consumed, LastReplyReceived is
205 // set to true. Do not use the message itself if LastReplyReceived is true - it won't be filled with actual data.
206 // Error will be returned if the response cannot be received or decoded.
207 func (req *MultiRequestCtx) ReceiveReply(msg Message) (LastReplyReceived bool, err error) {
208 if req == nil || req.ch == nil {
209 return false, errors.New("invalid request context")
212 return req.ch.receiveReplyInternal(msg)
215 // receiveReplyInternal receives a reply from the reply channel into the provided msg structure.
216 func (ch *Channel) receiveReplyInternal(msg Message) (LastReplyReceived bool, err error) {
218 return false, errors.New("nil message passed in")
221 timer := time.NewTimer(ch.replyTimeout)
224 // blocks until a reply comes to ReplyChan or until timeout expires
225 case vppReply := <-ch.ReplyChan:
226 if vppReply.Error != nil {
230 if vppReply.LastReplyReceived {
231 LastReplyReceived = true
235 expMsgID, err := ch.MsgIdentifier.GetMessageID(msg)
237 err = fmt.Errorf("message %s with CRC %s is not compatible with the VPP we are connected to",
238 msg.GetMessageName(), msg.GetCrcString())
241 if vppReply.MessageID != expMsgID {
243 logrus.Warnf("received invalid message ID, expected %d (%s), but got %d (probably timed out reply from previous request)",
244 expMsgID, msg.GetMessageName(), vppReply.MessageID)
247 err = fmt.Errorf("received invalid message ID, expected %d (%s), but got %d (check if multiple goroutines are not sharing single GoVPP channel)",
248 expMsgID, msg.GetMessageName(), vppReply.MessageID)
251 ch.lastTimedOut = false
252 // decode the message
253 err = ch.MsgDecoder.DecodeMsg(vppReply.Data, msg)
256 ch.lastTimedOut = true
257 err = fmt.Errorf("no reply received within the timeout period %s", ch.replyTimeout)
264 // SubscribeNotification subscribes for receiving of the specified notification messages via provided Go channel.
265 // Note that the caller is responsible for creating the Go channel with preferred buffer size. If the channel's
266 // buffer is full, the notifications will not be delivered into it.
267 func (ch *Channel) SubscribeNotification(notifChan chan Message, msgFactory func() Message) (*NotifSubscription, error) {
268 subscription := &NotifSubscription{
269 NotifChan: notifChan,
270 MsgFactory: msgFactory,
272 ch.NotifSubsChan <- &NotifSubscribeRequest{
273 Subscription: subscription,
276 return subscription, <-ch.NotifSubsReplyChan
279 // UnsubscribeNotification unsubscribes from receiving the notifications tied to the provided notification subscription.
280 func (ch *Channel) UnsubscribeNotification(subscription *NotifSubscription) error {
281 ch.NotifSubsChan <- &NotifSubscribeRequest{
282 Subscription: subscription,
285 return <-ch.NotifSubsReplyChan
288 // CheckMessageCompatibility checks whether provided messages are compatible with the version of VPP
289 // which the library is connected to.
290 func (ch *Channel) CheckMessageCompatibility(messages ...Message) error {
291 for _, msg := range messages {
292 _, err := ch.MsgIdentifier.GetMessageID(msg)
294 return fmt.Errorf("message %s with CRC %s is not compatible with the VPP we are connected to",
295 msg.GetMessageName(), msg.GetCrcString())