feat: Add stats poller service for retrieving VPP stats

api/configurator/configurator.proto

@@ -23,6 +23,12 @@ message Notification {
     }
 }
 
+message Stats {
+    oneof stats {
+        vpp.Stats vpp_stats = 1;
+    }
+}
+
 // Configurator provides basic operations for managing configuration
 // and monitoring state.
 service Configurator {
@@ -95,3 +101,20 @@ message NotificationResponse {
     // Notification data
     Notification notification = 2;
 }
+
+// StatsPoller provides operations for retrieving statistics.
+service StatsPoller {
+    // PollStats is used for polling metrics using poll period.
+    rpc PollStats(PollStatsRequest) returns (stream PollStatsResponse) {};
+}
+
+message PollStatsRequest {
+    // PeriodSec defines polling period (in seconds)
+    uint32 period_sec = 1;
+}
+
+
+message PollStatsResponse {
+    uint32 poll_seq = 1;
+    Stats stats = 2;
+}

api/models/vpp/interfaces/state.proto

@@ -9,6 +9,35 @@ option (gogoproto.messagename_all) = true;
 
 import "models/vpp/interfaces/interface.proto";
 
+message InterfaceStats {
+    string name = 1;
+
+    message CombinedCounter {
+        uint64 packets = 1;
+        uint64 bytes = 2;
+    }
+    CombinedCounter rx = 2;
+    CombinedCounter tx = 3;
+
+    CombinedCounter rx_unicast = 4;
+    CombinedCounter rx_multicast = 5;
+    CombinedCounter rx_broadcast = 6;
+    CombinedCounter tx_unicast = 7;
+    CombinedCounter tx_multicast = 8;
+    CombinedCounter tx_broadcast = 9;
+
+    uint64 rx_error = 12;
+    uint64 tx_error = 13;
+
+    uint64 rx_no_buf = 10;
+    uint64 rx_miss = 11;
+    uint64 drops = 14;
+    uint64 punts = 15;
+    uint64 ip4 = 16;
+    uint64 ip6 = 17;
+    uint64 mpls = 18;
+}
+
 message InterfaceState {
     string name = 1;
     string internal_name = 2;

api/models/vpp/vpp.proto

@@ -56,3 +56,7 @@ message ConfigData {
 message Notification {
     interfaces.InterfaceNotification interface = 1;
 }
+
+message Stats {
+    interfaces.InterfaceStats interface = 1;
+}

examples/grpc_vpp/stats_poller/main.go

@@ -0,0 +1,115 @@
+//  Copyright (c) 2019 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 main
+
+import (
+	"log"
+	"net"
+	"time"
+
+	"github.com/ligato/cn-infra/agent"
+	"github.com/ligato/cn-infra/infra"
+	"github.com/namsral/flag"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+
+	"github.com/ligato/vpp-agent/api/configurator"
+)
+
+var (
+	address    = flag.String("address", "localhost:9111", "address of GRPC server")
+	socketType = flag.String("socket-type", "tcp", "[tcp, tcp4, tcp6, unix, unixpacket]")
+	period     = flag.Uint("period", 3, "Polling period (in seconds)")
+)
+
+func main() {
+	ep := &ExamplePlugin{}
+	ep.SetName("stats-poller-example")
+	ep.Setup()
+
+	a := agent.NewAgent(
+		agent.AllPlugins(ep),
+	)
+	if err := a.Run(); err != nil {
+		log.Fatal()
+	}
+}
+
+// ExamplePlugin demonstrates the use of grpc to watch on VPP notifications using vpp-agent.
+type ExamplePlugin struct {
+	infra.PluginDeps
+
+	conn *grpc.ClientConn
+}
+
+// Init initializes example plugin.
+func (p *ExamplePlugin) Init() (err error) {
+	// Set up connection to the server.
+	p.conn, err = grpc.Dial("unix",
+		grpc.WithInsecure(),
+		grpc.WithDialer(dialer(*socketType, *address, time.Second*3)))
+
+	if err != nil {
+		return err
+	}
+
+	client := configurator.NewStatsPollerClient(p.conn)
+
+	// Start stats poller.
+	go p.pollStats(client)
+
+	return err
+}
+
+// Get is an implementation of client-side statistics streaming.
+func (p *ExamplePlugin) pollStats(client configurator.StatsPollerClient) {
+	p.Log.Infof("Polling every %v seconds..", *period)
+
+	req := &configurator.PollStatsRequest{
+		PeriodSec: uint32(*period),
+	}
+
+	ctx := context.Background()
+	stream, err := client.PollStats(ctx, req)
+	if err != nil {
+		p.Log.Fatalln("PollStats failed:", err)
+	}
+
+	var lastSeq uint32
+	for {
+		resp, err := stream.Recv()
+		if err != nil {
+			p.Log.Fatalln("Recv failed:", err)
+		}
+
+		if resp.PollSeq != lastSeq {
+			p.Log.Infof(" --- Poll sequence: %-3v", resp.PollSeq)
+		}
+		lastSeq = resp.PollSeq
+
+		vppStats := resp.GetStats().GetVppStats()
+		p.Log.Infof("VPP stats: %v", vppStats)
+	}
+}
+
+// Dialer for unix domain socket
+func dialer(socket, address string, timeoutVal time.Duration) func(string, time.Duration) (net.Conn, error) {
+	return func(addr string, timeout time.Duration) (net.Conn, error) {
+		// Pass values
+		addr, timeout = address, timeoutVal
+		// Dial with timeout
+		return net.DialTimeout(socket, addr, timeoutVal)
+	}
+}

plugins/govppmux/mock/mock_govppmux.go

@@ -68,15 +68,15 @@ func (p *GoVPPMux) ListStats(patterns ...string) ([]string, error) {
 }
 
 // DumpStats dumps stats from mocked stats API
-func (p *GoVPPMux) DumpStats(patterns ...string) ([]*adapter.StatEntry, error) {
+func (p *GoVPPMux) DumpStats(patterns ...string) ([]adapter.StatEntry, error) {
 	if p.stats == nil {
 		return nil, fmt.Errorf("failed to dump VPP stats, nil stats adapter")
 	}
 	return p.stats.DumpStats(patterns...)
 }
 
 // MockStats allows to set required stats which are then returned by 'ListStats' or 'DumpStats'
-func (p *GoVPPMux) MockStats(stats []*adapter.StatEntry) error {
+func (p *GoVPPMux) MockStats(stats []adapter.StatEntry) error {
 	if p.stats == nil {
 		return fmt.Errorf("failed to mock VPP stats, nil stats adapter")
 	}