1 // Copyright (c) 2021 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 // Connection represents the client connection to VPP API.
24 // NOTE: This API is EXPERIMENTAL.
25 type Connection interface {
26 // NewStream creates a new stream for sending and receiving messages.
27 // Context can be used to close the stream using cancel or timeout.
28 NewStream(ctx context.Context, options ...StreamOption) (Stream, error)
30 // Invoke can be used for a simple request-reply RPC.
31 // It creates stream and calls SendMsg with req and RecvMsg which returns
33 Invoke(ctx context.Context, req Message, reply Message) error
36 // Stream provides low-level access for sending and receiving messages.
37 // Users should handle correct type and ordering of messages.
39 // It is not safe to call these methods on the same stream in different
42 // NOTE: This API is EXPERIMENTAL.
43 type Stream interface {
44 // SendMsg sends a message to the client.
45 // It blocks until message is sent to the transport.
46 SendMsg(Message) error
48 // RecvMsg blocks until a message is received or error occurs.
49 RecvMsg() (Message, error)
51 // Close closes the stream. Calling SendMsg and RecvMsg will return error
52 // after closing stream.
56 // StreamOption allows customizing a Stream. Available options are:
60 type StreamOption func(Stream)
62 // ChannelProvider provides the communication channel with govpp core.
63 type ChannelProvider interface {
64 // NewAPIChannel returns a new channel for communication with VPP via govpp core.
65 // It uses default buffer sizes for the request and reply Go channels.
66 NewAPIChannel() (Channel, error)
68 // NewAPIChannelBuffered returns a new channel for communication with VPP via govpp core.
69 // It allows to specify custom buffer sizes for the request and reply Go channels.
70 NewAPIChannelBuffered(reqChanBufSize, replyChanBufSize int) (Channel, error)
73 // Channel provides methods for direct communication with VPP channel.
74 type Channel interface {
75 // SendRequest asynchronously sends a request to VPP. Returns a request context, that can be used to call ReceiveReply.
76 // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply).
77 SendRequest(msg Message) RequestCtx
79 // SendMultiRequest asynchronously sends a multipart request (request to which multiple responses are expected) to VPP.
80 // Returns a multipart request context, that can be used to call ReceiveReply.
81 // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply).
82 SendMultiRequest(msg Message) MultiRequestCtx
84 // SubscribeNotification subscribes for receiving of the specified notification messages via provided Go channel.
85 // Note that the caller is responsible for creating the Go channel with preferred buffer size. If the channel's
86 // buffer is full, the notifications will not be delivered into it.
87 SubscribeNotification(notifChan chan Message, event Message) (SubscriptionCtx, error)
89 // SetReplyTimeout sets the timeout for replies from VPP. It represents the maximum time the API waits for a reply
90 // from VPP before returning an error.
91 SetReplyTimeout(timeout time.Duration)
93 // CheckCompatibility checks the compatiblity for the given messages.
94 // It will return an error if any of the given messages are not compatible.
95 CheckCompatiblity(msgs ...Message) error
97 // Close closes the API channel and releases all API channel-related resources
98 // in the ChannelProvider.
102 // RequestCtx is helper interface which allows to receive reply on request.
103 type RequestCtx interface {
104 // ReceiveReply receives a reply from VPP (blocks until a reply is delivered
105 // from VPP, or until an error occurs). The reply will be decoded into the msg
106 // argument. Error will be returned if the response cannot be received or decoded.
107 ReceiveReply(msg Message) error
110 // MultiRequestCtx is helper interface which allows to receive reply on multi-request.
111 type MultiRequestCtx interface {
112 // ReceiveReply receives a reply from VPP (blocks until a reply is delivered
113 // from VPP, or until an error occurs).The reply will be decoded into the msg
114 // argument. If the last reply has been already consumed, lastReplyReceived is
115 // set to true. Do not use the message itself if lastReplyReceived is
116 // true - it won't be filled with actual data.Error will be returned if the
117 // response cannot be received or decoded.
118 ReceiveReply(msg Message) (lastReplyReceived bool, err error)
121 // SubscriptionCtx is helper interface which allows to control subscription for
122 // notification events.
123 type SubscriptionCtx interface {
124 // Unsubscribe unsubscribes from receiving the notifications tied to the
125 // subscription context.