-// 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
}
Code Review / govpp.git / blobdiff