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.
23 // MessageType represents the type of a VPP message.
27 // RequestMessage represents a VPP request message
28 RequestMessage MessageType = iota
29 // ReplyMessage represents a VPP reply message
31 // OtherMessage represents other VPP message (e.g. counters)
35 // Message is an interface that is implemented by all VPP Binary API messages generated by the binapi_generator.
36 type Message interface {
37 // GetMessageName returns the original VPP name of the message, as defined in the VPP API.
38 GetMessageName() string
40 // GetMessageType returns the type of the VPP message.
41 GetMessageType() MessageType
43 // GetCrcString returns the string with CRC checksum of the message definition (the string represents a hexadecimal number).
47 // DataType is an interface that is implemented by all VPP Binary API data types by the binapi_generator.
48 type DataType interface {
49 // GetTypeName returns the original VPP name of the data type, as defined in the VPP API.
52 // GetCrcString returns the string with CRC checksum of the data type definition (the string represents a hexadecimal number).
56 // ChannelProvider provides the communication channel with govpp core.
57 type ChannelProvider interface {
58 // NewAPIChannel returns a new channel for communication with VPP via govpp core.
59 // It uses default buffer sizes for the request and reply Go channels.
60 NewAPIChannel() (*Channel, error)
62 // NewAPIChannel returns a new channel for communication with VPP via govpp core.
63 // It allows to specify custom buffer sizes for the request and reply Go channels.
64 NewAPIChannelBuffered() (*Channel, error)
67 // MessageDecoder provides functionality for decoding binary data to generated API messages.
68 type MessageDecoder interface {
69 // DecodeMsg decodes binary-encoded data of a message into provided Message structure.
70 DecodeMsg(data []byte, msg Message) error
73 // MessageIdentifier provides identification of generated API messages.
74 type MessageIdentifier interface {
75 // GetMessageID returns message identifier of given API message.
76 GetMessageID(msg Message) (uint16, error)
79 // Channel is the main communication interface with govpp core. It contains two Go channels, one for sending the requests
80 // to VPP and one for receiving the replies from it. The user can access the Go channels directly, or use the helper
81 // methods provided inside of this package.
83 ReqChan chan *VppRequest // channel for sending the requests to VPP, closing this channel releases all resources in the ChannelProvider
84 ReplyChan chan *VppReply // channel where VPP replies are delivered to
86 NotifSubsChan chan *NotifSubscribeRequest // channel for sending notification subscribe requests
87 NotifSubsReplyChan chan error // channel where replies to notification subscribe requests are delivered to
89 MsgDecoder MessageDecoder // used to decode binary data to generated API messages
90 MsgIdentifier MessageIdentifier // used to retrieve message ID of a message
92 replyTimeout time.Duration // maximum time that the API waits for a reply from VPP before returning an error, can be set with SetReplyTimeout
93 metadata interface{} // opaque metadata of the API channel
96 // VppRequest is a request that will be sent to VPP.
97 type VppRequest struct {
98 Message Message // binary API message to be send to VPP
99 Multipart bool // true if multipart response is expected, false otherwise
102 // VppReply is a reply received from VPP.
103 type VppReply struct {
104 MessageID uint16 // ID of the message
105 Data []byte // encoded data with the message - MessageDecoder can be used for decoding
106 LastReplyReceived bool // in case of multipart replies, true if the last reply has been already received and this one should be ignored
107 Error error // in case of error, data is nil and this member contains error description
110 // NotifSubscribeRequest is a request to subscribe for delivery of specific notification messages.
111 type NotifSubscribeRequest struct {
112 Subscription *NotifSubscription // subscription details
113 Subscribe bool // true if this is a request to subscribe, false if unsubscribe
116 // NotifSubscription represents a subscription for delivery of specific notification messages.
117 type NotifSubscription struct {
118 NotifChan chan Message // channel where notification messages will be delivered to
119 MsgFactory func() Message // function that returns a new instance of the specific message that is expected as a notification
122 // RequestCtx is a context of a ongoing request (simple one - only one response is expected).
123 type RequestCtx struct {
127 // MultiRequestCtx is a context of a ongoing multipart request (multiple responses are expected).
128 type MultiRequestCtx struct {
132 const defaultReplyTimeout = time.Second * 1 // default timeout for replies from VPP, can be changed with SetReplyTimeout
134 // NewChannelInternal returns a new channel structure with metadata field filled in with the provided argument.
135 // Note that this is just a raw channel not yet connected to VPP, it is not intended to be used directly.
136 // Use ChannelProvider to get an API channel ready for communication with VPP.
137 func NewChannelInternal(metadata interface{}) *Channel {
139 replyTimeout: defaultReplyTimeout,
144 // Metadata returns the metadata stored within the channel structure by the NewChannelInternal call.
145 func (ch *Channel) Metadata() interface{} {
149 // SetReplyTimeout sets the timeout for replies from VPP. It represents the maximum time the API waits for a reply
150 // from VPP before returning an error.
151 func (ch *Channel) SetReplyTimeout(timeout time.Duration) {
152 ch.replyTimeout = timeout
155 // Close closes the API channel and releases all API channel-related resources in the ChannelProvider.
156 func (ch *Channel) Close() {
157 if ch.ReqChan != nil {
162 // SendRequest asynchronously sends a request to VPP. Returns a request context, that can be used to call ReceiveReply.
163 // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply).
164 func (ch *Channel) SendRequest(msg Message) *RequestCtx {
165 ch.ReqChan <- &VppRequest{
168 return &RequestCtx{ch: ch}
171 // ReceiveReply receives a reply from VPP (blocks until a reply is delivered from VPP, or until an error occurs).
172 // The reply will be decoded into the msg argument. Error will be returned if the response cannot be received or decoded.
173 func (req *RequestCtx) ReceiveReply(msg Message) error {
174 if req == nil || req.ch == nil {
175 return errors.New("invalid request context")
178 lastReplyReceived, err := req.ch.receiveReplyInternal(msg)
180 if lastReplyReceived {
181 err = errors.New("multipart reply recieved while a simple reply expected")
186 // SendMultiRequest asynchronously sends a multipart request (request to which multiple responses are expected) to VPP.
187 // Returns a multipart request context, that can be used to call ReceiveReply.
188 // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply).
189 func (ch *Channel) SendMultiRequest(msg Message) *MultiRequestCtx {
190 ch.ReqChan <- &VppRequest{
194 return &MultiRequestCtx{ch: ch}
197 // ReceiveReply receives a reply from VPP (blocks until a reply is delivered from VPP, or until an error occurs).
198 // The reply will be decoded into the msg argument. If the last reply has been already consumed, LastReplyReceived is
199 // set to true. Do not use the message itself if LastReplyReceived is true - it won't be filled with actual data.
200 // Error will be returned if the response cannot be received or decoded.
201 func (req *MultiRequestCtx) ReceiveReply(msg Message) (LastReplyReceived bool, err error) {
202 if req == nil || req.ch == nil {
203 return false, errors.New("invalid request context")
206 return req.ch.receiveReplyInternal(msg)
209 // receiveReplyInternal receives a reply from the reply channel into the provided msg structure.
210 func (ch *Channel) receiveReplyInternal(msg Message) (LastReplyReceived bool, err error) {
212 return false, errors.New("nil message passed in")
215 // blocks until a reply comes to ReplyChan or until timeout expires
216 case vppReply := <-ch.ReplyChan:
217 if vppReply.Error != nil {
221 if vppReply.LastReplyReceived {
222 LastReplyReceived = true
226 expMsgID, err := ch.MsgIdentifier.GetMessageID(msg)
228 err = fmt.Errorf("message %s with CRC %s is not compatible with the VPP we are connected to",
229 msg.GetMessageName(), msg.GetCrcString())
232 if vppReply.MessageID != expMsgID {
233 err = fmt.Errorf("invalid message ID %d, expected %d", vppReply.MessageID, expMsgID)
236 // decode the message
237 err = ch.MsgDecoder.DecodeMsg(vppReply.Data, msg)
239 case <-time.After(ch.replyTimeout):
240 err = fmt.Errorf("no reply received within the timeout period %ds", ch.replyTimeout/time.Second)
245 // SubscribeNotification subscribes for receiving of the specified notification messages via provided Go channel.
246 // Note that the caller is responsible for creating the Go channel with preferred buffer size. If the channel's
247 // buffer is full, the notifications will not be delivered into it.
248 func (ch *Channel) SubscribeNotification(notifChan chan Message, msgFactory func() Message) (*NotifSubscription, error) {
249 subscription := &NotifSubscription{
250 NotifChan: notifChan,
251 MsgFactory: msgFactory,
253 ch.NotifSubsChan <- &NotifSubscribeRequest{
254 Subscription: subscription,
257 return subscription, <-ch.NotifSubsReplyChan
260 // UnsubscribeNotification unsubscribes from receiving the notifications tied to the provided notification subscription.
261 func (ch *Channel) UnsubscribeNotification(subscription *NotifSubscription) error {
262 ch.NotifSubsChan <- &NotifSubscribeRequest{
263 Subscription: subscription,
266 return <-ch.NotifSubsReplyChan
269 // CheckMessageCompatibility checks whether provided messages are compatible with the version of VPP
270 // which the library is connected to.
271 func (ch *Channel) CheckMessageCompatibility(messages ...Message) error {
272 for _, msg := range messages {
273 _, err := ch.MsgIdentifier.GetMessageID(msg)
275 return fmt.Errorf("message %s with CRC %s is not compatible with the VPP we are connected to",
276 msg.GetMessageName(), msg.GetCrcString())