X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=api%2Fapi.go;h=c4f069faadcfbf840eafab03785f443c2ee65b86;hb=a4112fac7b86fe09650d2bb57969fe46404edd7d;hp=98932fa38b8f271917c4cd6bb5955b1152b835de;hpb=40cdb18263ac2624c5a007ef1b0ac7d1b21974bd;p=govpp.git diff --git a/api/api.go b/api/api.go index 98932fa..c4f069f 100644 --- a/api/api.go +++ b/api/api.go @@ -1,284 +1,127 @@ -// Copyright (c) 2017 Cisco and/or its affiliates. +// Copyright (c) 2021 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: +// 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 +// 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. +// 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 api import ( - "errors" - "fmt" + "context" "time" ) -// MessageType represents the type of a VPP message. -type MessageType int +// Connection represents the client connection to VPP API. +// +// NOTE: This API is EXPERIMENTAL. +type Connection interface { + // NewStream creates a new stream for sending and receiving messages. + // Context can be used to close the stream using cancel or timeout. + NewStream(ctx context.Context, options ...StreamOption) (Stream, error) -const ( - // RequestMessage represents a VPP request message - RequestMessage MessageType = iota - // ReplyMessage represents a VPP reply message - ReplyMessage - // EventMessage represents a VPP notification event message - EventMessage - // OtherMessage represents other VPP message (e.g. counters) - OtherMessage -) + // Invoke can be used for a simple request-reply RPC. + // It creates stream and calls SendMsg with req and RecvMsg which returns + // reply. + Invoke(ctx context.Context, req Message, reply Message) error +} -// Message is an interface that is implemented by all VPP Binary API messages generated by the binapigenerator. -type Message interface { - // GetMessageName returns the original VPP name of the message, as defined in the VPP API. - GetMessageName() string +// Stream provides low-level access for sending and receiving messages. +// Users should handle correct type and ordering of messages. +// +// It is not safe to call these methods on the same stream in different +// goroutines. +// +// NOTE: This API is EXPERIMENTAL. +type Stream interface { + // SendMsg sends a message to the client. + // It blocks until message is sent to the transport. + SendMsg(Message) error - // GetMessageType returns the type of the VPP message. - GetMessageType() MessageType + // RecvMsg blocks until a message is received or error occurs. + RecvMsg() (Message, error) - // GetCrcString returns the string with CRC checksum of the message definition (the string represents a hexadecimal number). - GetCrcString() string + // Close closes the stream. Calling SendMsg and RecvMsg will return error + // after closing stream. + Close() error } -// DataType is an interface that is implemented by all VPP Binary API data types by the binapi_generator. -type DataType interface { - // GetTypeName returns the original VPP name of the data type, as defined in the VPP API. - GetTypeName() string - - // GetCrcString returns the string with CRC checksum of the data type definition (the string represents a hexadecimal number). - GetCrcString() string -} +// StreamOption allows customizing a Stream. Available options are: +// - WithRequestSize +// - WithReplySize +// - WithReplyTimeout +type StreamOption func(Stream) // ChannelProvider provides the communication channel with govpp core. type ChannelProvider interface { // NewAPIChannel returns a new channel for communication with VPP via govpp core. // It uses default buffer sizes for the request and reply Go channels. - NewAPIChannel() (*Channel, error) + NewAPIChannel() (Channel, error) - // NewAPIChannel returns a new channel for communication with VPP via govpp core. + // NewAPIChannelBuffered returns a new channel for communication with VPP via govpp core. // It allows to specify custom buffer sizes for the request and reply Go channels. - NewAPIChannelBuffered() (*Channel, error) -} - -// MessageDecoder provides functionality for decoding binary data to generated API messages. -type MessageDecoder interface { - // DecodeMsg decodes binary-encoded data of a message into provided Message structure. - DecodeMsg(data []byte, msg Message) error -} - -// MessageIdentifier provides identification of generated API messages. -type MessageIdentifier interface { - // GetMessageID returns message identifier of given API message. - GetMessageID(msg Message) (uint16, error) -} - -// Channel is the main communication interface with govpp core. It contains two Go channels, one for sending the requests -// to VPP and one for receiving the replies from it. The user can access the Go channels directly, or use the helper -// methods provided inside of this package. Do not use the same channel from multiple goroutines concurrently, -// otherwise the responses could mix! Use multiple channels instead. -type Channel struct { - ReqChan chan *VppRequest // channel for sending the requests to VPP, closing this channel releases all resources in the ChannelProvider - ReplyChan chan *VppReply // channel where VPP replies are delivered to - - NotifSubsChan chan *NotifSubscribeRequest // channel for sending notification subscribe requests - NotifSubsReplyChan chan error // channel where replies to notification subscribe requests are delivered to - - MsgDecoder MessageDecoder // used to decode binary data to generated API messages - MsgIdentifier MessageIdentifier // used to retrieve message ID of a message - - replyTimeout time.Duration // maximum time that the API waits for a reply from VPP before returning an error, can be set with SetReplyTimeout - metadata interface{} // opaque metadata of the API channel -} - -// VppRequest is a request that will be sent to VPP. -type VppRequest struct { - Message Message // binary API message to be send to VPP - Multipart bool // true if multipart response is expected, false otherwise -} - -// VppReply is a reply received from VPP. -type VppReply struct { - MessageID uint16 // ID of the message - Data []byte // encoded data with the message - MessageDecoder can be used for decoding - LastReplyReceived bool // in case of multipart replies, true if the last reply has been already received and this one should be ignored - Error error // in case of error, data is nil and this member contains error description -} - -// NotifSubscribeRequest is a request to subscribe for delivery of specific notification messages. -type NotifSubscribeRequest struct { - Subscription *NotifSubscription // subscription details - Subscribe bool // true if this is a request to subscribe, false if unsubscribe -} - -// NotifSubscription represents a subscription for delivery of specific notification messages. -type NotifSubscription struct { - NotifChan chan Message // channel where notification messages will be delivered to - MsgFactory func() Message // function that returns a new instance of the specific message that is expected as a notification -} - -// RequestCtx is a context of a ongoing request (simple one - only one response is expected). -type RequestCtx struct { - ch *Channel -} - -// MultiRequestCtx is a context of a ongoing multipart request (multiple responses are expected). -type MultiRequestCtx struct { - ch *Channel -} - -const defaultReplyTimeout = time.Second * 1 // default timeout for replies from VPP, can be changed with SetReplyTimeout - -// NewChannelInternal returns a new channel structure with metadata field filled in with the provided argument. -// Note that this is just a raw channel not yet connected to VPP, it is not intended to be used directly. -// Use ChannelProvider to get an API channel ready for communication with VPP. -func NewChannelInternal(metadata interface{}) *Channel { - return &Channel{ - replyTimeout: defaultReplyTimeout, - metadata: metadata, - } -} - -// Metadata returns the metadata stored within the channel structure by the NewChannelInternal call. -func (ch *Channel) Metadata() interface{} { - return ch.metadata -} - -// SetReplyTimeout sets the timeout for replies from VPP. It represents the maximum time the API waits for a reply -// from VPP before returning an error. -func (ch *Channel) SetReplyTimeout(timeout time.Duration) { - ch.replyTimeout = timeout -} - -// Close closes the API channel and releases all API channel-related resources in the ChannelProvider. -func (ch *Channel) Close() { - if ch.ReqChan != nil { - close(ch.ReqChan) - } -} - -// SendRequest asynchronously sends a request to VPP. Returns a request context, that can be used to call ReceiveReply. -// In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply). -func (ch *Channel) SendRequest(msg Message) *RequestCtx { - ch.ReqChan <- &VppRequest{ - Message: msg, - } - return &RequestCtx{ch: ch} -} - -// ReceiveReply receives a reply from VPP (blocks until a reply is delivered from VPP, or until an error occurs). -// The reply will be decoded into the msg argument. Error will be returned if the response cannot be received or decoded. -func (req *RequestCtx) ReceiveReply(msg Message) error { - if req == nil || req.ch == nil { - return errors.New("invalid request context") - } - - lastReplyReceived, err := req.ch.receiveReplyInternal(msg) - - if lastReplyReceived { - err = errors.New("multipart reply recieved while a simple reply expected") - } - return err -} - -// SendMultiRequest asynchronously sends a multipart request (request to which multiple responses are expected) to VPP. -// Returns a multipart request context, that can be used to call ReceiveReply. -// In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply). -func (ch *Channel) SendMultiRequest(msg Message) *MultiRequestCtx { - ch.ReqChan <- &VppRequest{ - Message: msg, - Multipart: true, - } - return &MultiRequestCtx{ch: ch} -} - -// ReceiveReply receives a reply from VPP (blocks until a reply is delivered from VPP, or until an error occurs). -// The reply will be decoded into the msg argument. If the last reply has been already consumed, LastReplyReceived is -// set to true. Do not use the message itself if LastReplyReceived is true - it won't be filled with actual data. -// Error will be returned if the response cannot be received or decoded. -func (req *MultiRequestCtx) ReceiveReply(msg Message) (LastReplyReceived bool, err error) { - if req == nil || req.ch == nil { - return false, errors.New("invalid request context") - } - - return req.ch.receiveReplyInternal(msg) -} - -// receiveReplyInternal receives a reply from the reply channel into the provided msg structure. -func (ch *Channel) receiveReplyInternal(msg Message) (LastReplyReceived bool, err error) { - if msg == nil { - return false, errors.New("nil message passed in") - } - select { - // blocks until a reply comes to ReplyChan or until timeout expires - case vppReply := <-ch.ReplyChan: - if vppReply.Error != nil { - err = vppReply.Error - return - } - if vppReply.LastReplyReceived { - LastReplyReceived = true - return - } - // message checks - expMsgID, err := ch.MsgIdentifier.GetMessageID(msg) - if err != nil { - err = fmt.Errorf("message %s with CRC %s is not compatible with the VPP we are connected to", - msg.GetMessageName(), msg.GetCrcString()) - return false, err - } - if vppReply.MessageID != expMsgID { - err = fmt.Errorf("received invalid message ID, expected %d (%s), but got %d (check if multiple goroutines are not sharing single GoVPP channel)", - expMsgID, msg.GetMessageName(), vppReply.MessageID) - return false, err - } - // decode the message - err = ch.MsgDecoder.DecodeMsg(vppReply.Data, msg) - - case <-time.After(ch.replyTimeout): - err = fmt.Errorf("no reply received within the timeout period %s", ch.replyTimeout) - } - return -} - -// SubscribeNotification subscribes for receiving of the specified notification messages via provided Go channel. -// Note that the caller is responsible for creating the Go channel with preferred buffer size. If the channel's -// buffer is full, the notifications will not be delivered into it. -func (ch *Channel) SubscribeNotification(notifChan chan Message, msgFactory func() Message) (*NotifSubscription, error) { - subscription := &NotifSubscription{ - NotifChan: notifChan, - MsgFactory: msgFactory, - } - ch.NotifSubsChan <- &NotifSubscribeRequest{ - Subscription: subscription, - Subscribe: true, - } - return subscription, <-ch.NotifSubsReplyChan -} - -// UnsubscribeNotification unsubscribes from receiving the notifications tied to the provided notification subscription. -func (ch *Channel) UnsubscribeNotification(subscription *NotifSubscription) error { - ch.NotifSubsChan <- &NotifSubscribeRequest{ - Subscription: subscription, - Subscribe: false, - } - return <-ch.NotifSubsReplyChan -} - -// CheckMessageCompatibility checks whether provided messages are compatible with the version of VPP -// which the library is connected to. -func (ch *Channel) CheckMessageCompatibility(messages ...Message) error { - for _, msg := range messages { - _, err := ch.MsgIdentifier.GetMessageID(msg) - if err != nil { - return fmt.Errorf("message %s with CRC %s is not compatible with the VPP we are connected to", - msg.GetMessageName(), msg.GetCrcString()) - } - } - return nil + NewAPIChannelBuffered(reqChanBufSize, replyChanBufSize int) (Channel, error) +} + +// Channel provides methods for direct communication with VPP channel. +type Channel interface { + // SendRequest asynchronously sends a request to VPP. Returns a request context, that can be used to call ReceiveReply. + // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply). + SendRequest(msg Message) RequestCtx + + // SendMultiRequest asynchronously sends a multipart request (request to which multiple responses are expected) to VPP. + // Returns a multipart request context, that can be used to call ReceiveReply. + // In case of any errors by sending, the error will be delivered to ReplyChan (and returned by ReceiveReply). + SendMultiRequest(msg Message) MultiRequestCtx + + // SubscribeNotification subscribes for receiving of the specified notification messages via provided Go channel. + // Note that the caller is responsible for creating the Go channel with preferred buffer size. If the channel's + // buffer is full, the notifications will not be delivered into it. + SubscribeNotification(notifChan chan Message, event Message) (SubscriptionCtx, error) + + // SetReplyTimeout sets the timeout for replies from VPP. It represents the maximum time the API waits for a reply + // from VPP before returning an error. + SetReplyTimeout(timeout time.Duration) + + // CheckCompatibility checks the compatiblity for the given messages. + // It will return an error if any of the given messages are not compatible. + CheckCompatiblity(msgs ...Message) error + + // Close closes the API channel and releases all API channel-related resources + // in the ChannelProvider. + Close() +} + +// RequestCtx is helper interface which allows to receive reply on request. +type RequestCtx interface { + // ReceiveReply receives a reply from VPP (blocks until a reply is delivered + // from VPP, or until an error occurs). The reply will be decoded into the msg + // argument. Error will be returned if the response cannot be received or decoded. + ReceiveReply(msg Message) error +} + +// MultiRequestCtx is helper interface which allows to receive reply on multi-request. +type MultiRequestCtx interface { + // ReceiveReply receives a reply from VPP (blocks until a reply is delivered + // from VPP, or until an error occurs).The reply will be decoded into the msg + // argument. If the last reply has been already consumed, lastReplyReceived is + // set to true. Do not use the message itself if lastReplyReceived is + // true - it won't be filled with actual data.Error will be returned if the + // response cannot be received or decoded. + ReceiveReply(msg Message) (lastReplyReceived bool, err error) +} + +// SubscriptionCtx is helper interface which allows to control subscription for +// notification events. +type SubscriptionCtx interface { + // Unsubscribe unsubscribes from receiving the notifications tied to the + // subscription context. + Unsubscribe() error }