Introduce higer-level API for retrieving statistics

- see stats-api example

Change-Id: I11d29d32b60d25238e75cb6b86ee34842348ab38
Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

1 files changed, 139 insertions, 0 deletions

diff --git a/api/binapi.go b/api/binapi.go
new file mode 100644
index 0000000..ac9f8a4
--- /dev/null
+++ b/api/binapi.go
@@ -0,0 +1,139 @@
+// Copyright (c) 2017 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:
+//
+//     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.
+
+package api
+
+import (
+	"time"
+)
+
+// MessageType represents the type of a VPP message.
+// Note: this is currently derived from the message header (fields),
+// and in many cases it does not represent the actual type of VPP message.
+// This means that some replies can be identified as requests, etc.
+// TODO: use services to identify type of message
+type MessageType int
+
+const (
+	// RequestMessage represents a VPP request message
+	RequestMessage MessageType = iota
+	// ReplyMessage represents a VPP reply message
+	ReplyMessage
+	// EventMessage represents a VPP event message
+	EventMessage
+	// OtherMessage represents other VPP message
+	OtherMessage
+)
+
+// 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 returns the string with CRC checksum of the message definition (the string represents a hexadecimal number).
+	GetCrcString() string
+
+	// GetMessageType returns the type of the VPP message.
+	GetMessageType() MessageType
+}
+
+// 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
+}
+
+// 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)
+
+	// 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(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
+}
+
+var registeredMessages = make(map[string]Message)
+
+// RegisterMessage is called from generated code to register message.
+func RegisterMessage(x Message, name string) {
+	name = x.GetMessageName() + "_" + x.GetCrcString()
+	/*if _, ok := registeredMessages[name]; ok {
+		panic(fmt.Errorf("govpp: duplicate message registered: %s (%s)", name, x.GetCrcString()))
+	}*/
+	registeredMessages[name] = x
+}
+
+// GetRegisteredMessages returns list of all registered messages.
+func GetRegisteredMessages() map[string]Message {
+	return registeredMessages
+}
+
+// GoVppAPIPackageIsVersion1 is referenced from generated binapi files
+// to assert that that code is compatible with this version of the GoVPP api package.
+const GoVppAPIPackageIsVersion1 = true