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)
81 // LookupByID looks up message name and crc by ID
82 LookupByID(ID uint16) (string, error)
85 // Channel is the main communication interface with govpp core. It contains two Go channels, one for sending the requests
86 // to VPP and one for receiving the replies from it. The user can access the Go channels directly, or use the helper
87 // methods provided inside of this package. Do not use the same channel from multiple goroutines concurrently,
88 // otherwise the responses could mix! Use multiple channels instead.
90 ReqChan chan *VppRequest // channel for sending the requests to VPP, closing this channel releases all resources in the ChannelProvider
91 ReplyChan chan *VppReply // channel where VPP replies are delivered to
93 NotifSubsChan chan *NotifSubscribeRequest // channel for sending notification subscribe requests
94 NotifSubsReplyChan chan error // channel where replies to notification subscribe requests are delivered to
96 MsgDecoder MessageDecoder // used to decode binary data to generated API messages
97 MsgIdentifier MessageIdentifier // used to retrieve message ID of a message
99 replyTimeout time.Duration // maximum time that the API waits for a reply from VPP before returning an error, can be set with SetReplyTimeout
100 metadata interface{} // opaque metadata of the API channel
101 lastTimedOut bool // wether last request timed out
104 // VppRequest is a request that will be sent to VPP.
105 type VppRequest struct {
106 Message Message // binary API message to be send to VPP
107 Multipart bool // true if multipart response is expected, false otherwise
110 // VppReply is a reply received from VPP.
111 type VppReply struct {
112 MessageID uint16 // ID of the message
113 Data []byte // encoded data with the message - MessageDecoder can be used for decoding
114 LastReplyReceived bool // in case of multipart replies, true if the last reply has been already received and this one should be ignored
115 Error error // in case of error, data is nil and this member contains error description
118 // NotifSubscribeRequest is a request to subscribe for delivery of specific notification messages.
119 type NotifSubscribeRequest struct {
120 Subscription *NotifSubscription // subscription details
121 Subscribe bool // true if this is a request to subscribe, false if unsubscribe
124 // NotifSubscription represents a subscription for delivery of specific notification messages.
125 type NotifSubscription struct {
126 NotifChan chan Message // channel where notification messages will be delivered to
127 MsgFactory func() Message // function that returns a new instance of the specific message that is expected as a notification
130 // RequestCtx is a context of a ongoing request (simple one - only one response is expected).
131 type RequestCtx struct {
135 // MultiRequestCtx is a context of a ongoing multipart request (multiple responses are expected).
136 type MultiRequestCtx struct {
140 const defaultReplyTimeout = time.Second * 1 // default timeout for replies from VPP, can be changed with SetReplyTimeout
142 // NewChannelInternal returns a new channel structure with metadata field filled in with the provided argument.
143 // Note that this is just a raw channel not yet connected to VPP, it is not intended to be used directly.
144 // Use ChannelProvider to get an API channel ready for communication with VPP.
145 func NewChannelInternal(metadata interface{}) *Channel {
147 replyTimeout: defaultReplyTimeout,
152 // Metadata returns the metadata stored within the channel structure by the NewChannelInternal call.
153 func (ch *Channel) Metadata() interface{} {
157 // SetReplyTimeout sets the timeout for replies from VPP. It represents the maximum time the API waits for a reply
158 // from VPP before returning an error.
159 func (ch *Channel) SetReplyTimeout(timeout time.Duration) {
160 ch.replyTimeout = timeout
163 // Close closes the API channel and releases all API channel-related resources in the ChannelProvider.
164 func (ch *Channel) Close() {
165 if ch.ReqChan != nil {
170 // SendRequest asynchronously sends a request to VPP. Returns a request context, that can be used to call ReceiveReply.
171 // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply).
172 func (ch *Channel) SendRequest(msg Message) *RequestCtx {
173 ch.ReqChan <- &VppRequest{
176 return &RequestCtx{ch: ch}
179 // ReceiveReply receives a reply from VPP (blocks until a reply is delivered from VPP, or until an error occurs).
180 // The reply will be decoded into the msg argument. Error will be returned if the response cannot be received or decoded.
181 func (req *RequestCtx) ReceiveReply(msg Message) error {
182 if req == nil || req.ch == nil {
183 return errors.New("invalid request context")
186 lastReplyReceived, err := req.ch.receiveReplyInternal(msg)
188 if lastReplyReceived {
189 err = errors.New("multipart reply recieved while a simple reply expected")
194 // SendMultiRequest asynchronously sends a multipart request (request to which multiple responses are expected) to VPP.
195 // Returns a multipart request context, that can be used to call ReceiveReply.
196 // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply).
197 func (ch *Channel) SendMultiRequest(msg Message) *MultiRequestCtx {
198 ch.ReqChan <- &VppRequest{
202 return &MultiRequestCtx{ch: ch}
205 // ReceiveReply receives a reply from VPP (blocks until a reply is delivered from VPP, or until an error occurs).
206 // The reply will be decoded into the msg argument. If the last reply has been already consumed, LastReplyReceived is
207 // set to true. Do not use the message itself if LastReplyReceived is true - it won't be filled with actual data.
208 // Error will be returned if the response cannot be received or decoded.
209 func (req *MultiRequestCtx) ReceiveReply(msg Message) (LastReplyReceived bool, err error) {
210 if req == nil || req.ch == nil {
211 return false, errors.New("invalid request context")
214 return req.ch.receiveReplyInternal(msg)
217 // receiveReplyInternal receives a reply from the reply channel into the provided msg structure.
218 func (ch *Channel) receiveReplyInternal(msg Message) (LastReplyReceived bool, err error) {
220 return false, errors.New("nil message passed in")
223 timer := time.NewTimer(ch.replyTimeout)
226 // blocks until a reply comes to ReplyChan or until timeout expires
227 case vppReply := <-ch.ReplyChan:
228 if vppReply.Error != nil {
232 if vppReply.LastReplyReceived {
233 LastReplyReceived = true
238 expMsgID, err := ch.MsgIdentifier.GetMessageID(msg)
240 err = fmt.Errorf("message %s with CRC %s is not compatible with the VPP we are connected to",
241 msg.GetMessageName(), msg.GetCrcString())
245 if vppReply.MessageID != expMsgID {
246 var msgNameCrc string
247 if nameCrc, err := ch.MsgIdentifier.LookupByID(vppReply.MessageID); err != nil {
248 msgNameCrc = err.Error()
254 logrus.Warnf("received invalid message ID, expected %d (%s), but got %d (%s) (probably timed out reply from previous request)",
255 expMsgID, msg.GetMessageName(), vppReply.MessageID, msgNameCrc)
259 err = fmt.Errorf("received invalid message ID, expected %d (%s), but got %d (%s) (check if multiple goroutines are not sharing single GoVPP channel)",
260 expMsgID, msg.GetMessageName(), vppReply.MessageID, msgNameCrc)
264 ch.lastTimedOut = false
265 // decode the message
266 err = ch.MsgDecoder.DecodeMsg(vppReply.Data, msg)
270 ch.lastTimedOut = true
271 err = fmt.Errorf("no reply received within the timeout period %s", ch.replyTimeout)
278 // SubscribeNotification subscribes for receiving of the specified notification messages via provided Go channel.
279 // Note that the caller is responsible for creating the Go channel with preferred buffer size. If the channel's
280 // buffer is full, the notifications will not be delivered into it.
281 func (ch *Channel) SubscribeNotification(notifChan chan Message, msgFactory func() Message) (*NotifSubscription, error) {
282 subscription := &NotifSubscription{
283 NotifChan: notifChan,
284 MsgFactory: msgFactory,
286 ch.NotifSubsChan <- &NotifSubscribeRequest{
287 Subscription: subscription,
290 return subscription, <-ch.NotifSubsReplyChan
293 // UnsubscribeNotification unsubscribes from receiving the notifications tied to the provided notification subscription.
294 func (ch *Channel) UnsubscribeNotification(subscription *NotifSubscription) error {
295 ch.NotifSubsChan <- &NotifSubscribeRequest{
296 Subscription: subscription,
299 return <-ch.NotifSubsReplyChan
302 // CheckMessageCompatibility checks whether provided messages are compatible with the version of VPP
303 // which the library is connected to.
304 func (ch *Channel) CheckMessageCompatibility(messages ...Message) error {
305 for _, msg := range messages {
306 _, err := ch.MsgIdentifier.GetMessageID(msg)
308 return fmt.Errorf("message %s with CRC %s is not compatible with the VPP we are connected to",
309 msg.GetMessageName(), msg.GetCrcString())