package api
import (
- "errors"
- "fmt"
"time"
)
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
)
-// Message is an interface that is implemented by all VPP Binary API messages generated by the binapi-generator.
+// 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
GetCrcString() string
}
-// DataType is an interface that is implemented by all VPP Binary API data types by the binapi-generator.
+// 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
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)
+ NewAPIChannelBuffered(reqChanBufSize, replyChanBufSize int) (Channel, error)
}
// MessageDecoder provides functionality for decoding binary data to 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
+ // LookupByID looks up message name and crc by ID
+ LookupByID(ID uint16) (string, 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, msgFactory func() Message) (*NotifSubscription, error)
+ // UnsubscribeNotification unsubscribes from receiving the notifications tied to the provided notification subscription.
+ UnsubscribeNotification(subscription *NotifSubscription) error
+ // CheckMessageCompatibility checks whether provided messages are compatible with the version of VPP
+ // which the library is connected to.
+ CheckMessageCompatibility(messages ...Message) 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)
+ // GetRequestChannel returns request go channel of the VPP channel
+ GetRequestChannel() chan<- *VppRequest
+ // GetReplyChannel returns reply go channel of the VPP channel
+ GetReplyChannel() <-chan *VppReply
+ // GetNotificationChannel returns notification go channel of the VPP channel
+ GetNotificationChannel() chan<- *NotifSubscribeRequest
+ // GetNotificationReplyChannel returns notification reply go channel of the VPP channel
+ GetNotificationReplyChannel() <-chan error
+ // GetMessageDecoder returns message decoder instance
+ GetMessageDecoder() MessageDecoder
+ // GetID returns channel's ID
+ GetID() uint16
+ // 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 context data
+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 context data
+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)
}
// VppRequest is a request that will be sent to VPP.
type VppRequest struct {
+ SeqNum uint16 // sequence number
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
+ SeqNum uint16 // sequence number
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
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("invalid message ID %d, expected %d "+
- "(also check if multiple goroutines are not sharing one GoVPP channel)", vppReply.MessageID, expMsgID)
- 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 %ds", ch.replyTimeout/time.Second)
- }
- 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
-}