added async connect API, new structure of examples

Change-Id: Iab9bce174596c30998981e02b7030c248c423384
Signed-off-by: Rastislav Szabo <raszabo@cisco.com>

2 files changed, 135 insertions, 60 deletions

diff --git a/examples/example_client.go b/examples/cmd/simple-client/simple_client.go
index f2e5804..6e46d6b 100644
--- a/examples/example_client.go
+++ b/examples/cmd/simple-client/simple_client.go
@@ -12,7 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Example VPP management application that exercises the govpp API on real-world use-cases.
+// Binary simple-client is an example VPP management application that exercises the
+// govpp API on real-world use-cases.
 package main
 
 // Generates Go bindings for all VPP APIs located in the json directory.
@@ -22,19 +23,16 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"os/signal"
 
 	"git.fd.io/govpp.git"
 	"git.fd.io/govpp.git/api"
-	"git.fd.io/govpp.git/api/ifcounters"
-	"git.fd.io/govpp.git/core/bin_api/vpe"
 	"git.fd.io/govpp.git/examples/bin_api/acl"
 	"git.fd.io/govpp.git/examples/bin_api/interfaces"
 	"git.fd.io/govpp.git/examples/bin_api/tap"
 )
 
 func main() {
-	fmt.Println("Starting example VPP client...")
+	fmt.Println("Starting simple VPP client...")
 
 	// connect to VPP
 	conn, err := govpp.Connect()
@@ -64,8 +62,6 @@ func main() {
 
 	interfaceDump(ch)
 	interfaceNotifications(ch)
-
-	//interfaceCounters(ch)
 }
 
 // compatibilityCheck shows how an management application can check whether generated API messages are
@@ -223,56 +219,3 @@ func interfaceNotifications(ch *api.Channel) {
 	// unsubscribe from delivery of the notifications
 	ch.UnsubscribeNotification(subs)
 }
-
-// interfaceCounters is an example of using notification API to periodically retrieve interface statistics.
-// The ifcounters package contains the API that can be used to decode the strange VnetInterfaceCounters message.
-func interfaceCounters(ch *api.Channel) {
-	// subscribe for interface counters notifications
-	notifChan := make(chan api.Message, 100)
-	subs, _ := ch.SubscribeNotification(notifChan, interfaces.NewVnetInterfaceCounters)
-
-	// enable interface counters notifications from VPP
-	ch.SendRequest(&vpe.WantStats{
-		Pid:           uint32(os.Getpid()),
-		EnableDisable: 1,
-	}).ReceiveReply(&vpe.WantStatsReply{})
-
-	// create channel for Interrupt signal
-	sigChan := make(chan os.Signal, 1)
-	signal.Notify(sigChan, os.Interrupt)
-
-	// loop until Interrupt signal is received
-loop:
-	for {
-		select {
-		case <-sigChan:
-			// interrupt received
-			break loop
-		case notifMsg := <-notifChan:
-			notif := notifMsg.(*interfaces.VnetInterfaceCounters)
-			// notification received
-			fmt.Printf("%+v\n", notif)
-
-			if notif.IsCombined == 0 {
-				// simple counter
-				counters, err := ifcounters.DecodeCounters(ifcounters.VnetInterfaceCounters(*notif))
-				if err != nil {
-					fmt.Println("Error:", err)
-				} else {
-					fmt.Printf("%+v\n", counters)
-				}
-			} else {
-				// combined counter
-				counters, err := ifcounters.DecodeCombinedCounters(ifcounters.VnetInterfaceCounters(*notif))
-				if err != nil {
-					fmt.Println("Error:", err)
-				} else {
-					fmt.Printf("%+v\n", counters)
-				}
-			}
-		}
-	}
-
-	// unsubscribe from delivery of the notifications
-	ch.UnsubscribeNotification(subs)
-}
diff --git a/examples/cmd/stats-client/stats_client.go b/examples/cmd/stats-client/stats_client.go
new file mode 100644
index 0000000..fc40b24
--- /dev/null
+++ b/examples/cmd/stats-client/stats_client.go
@@ -0,0 +1,132 @@
+// 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.
+
+// Binary stats-client is an example VPP management application that exercises the
+// govpp API for interface counters together with asynchronous connection to VPP.
+package main
+
+// Generates Go bindings for all VPP APIs located in the json directory.
+//go:generate binapi-generator --input-dir=bin_api --output-dir=bin_api
+
+import (
+	"fmt"
+	"os"
+	"os/signal"
+
+	"git.fd.io/govpp.git"
+	"git.fd.io/govpp.git/api"
+	"git.fd.io/govpp.git/api/ifcounters"
+	"git.fd.io/govpp.git/core"
+	"git.fd.io/govpp.git/core/bin_api/vpe"
+	"git.fd.io/govpp.git/examples/bin_api/interfaces"
+)
+
+func main() {
+	fmt.Println("Starting stats VPP client...")
+
+	// async connect to VPP
+	conn, statCh, err := govpp.AsyncConnect()
+	if err != nil {
+		fmt.Println("Error:", err)
+		os.Exit(1)
+	}
+	defer conn.Disconnect()
+
+	// create an API channel that will be used in the examples
+	ch, err := conn.NewAPIChannel()
+	if err != nil {
+		fmt.Println("Error:", err)
+		os.Exit(1)
+	}
+	defer ch.Close()
+
+	// create channel for Interrupt signal
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, os.Interrupt)
+
+	var subs *api.NotifSubscription
+	var notifChan chan api.Message
+
+	// loop until Interrupt signal is received
+loop:
+	for {
+		select {
+
+		case connEvent := <-statCh:
+			// VPP connection state change
+			switch connEvent.State {
+			case core.Connected:
+				fmt.Println("VPP connected.")
+				if subs == nil {
+					subs, notifChan = subscribeNotification(ch)
+				}
+				requestStatistics(ch)
+
+			case core.Disconnected:
+				fmt.Println("VPP disconnected.")
+			}
+
+		case notifMsg := <-notifChan:
+			// counter notification received
+			processCounters(notifMsg.(*interfaces.VnetInterfaceCounters))
+
+		case <-sigChan:
+			// interrupt received
+			fmt.Println("Interrupt received, exiting.")
+			break loop
+		}
+	}
+
+	ch.UnsubscribeNotification(subs)
+}
+
+// subscribeNotification subscribes for interface counters notifications.
+func subscribeNotification(ch *api.Channel) (*api.NotifSubscription, chan api.Message) {
+
+	notifChan := make(chan api.Message, 100)
+	subs, _ := ch.SubscribeNotification(notifChan, interfaces.NewVnetInterfaceCounters)
+
+	return subs, notifChan
+}
+
+// requestStatistics requests interface counters notifications from VPP.
+func requestStatistics(ch *api.Channel) {
+	ch.SendRequest(&vpe.WantStats{
+		Pid:           uint32(os.Getpid()),
+		EnableDisable: 1,
+	}).ReceiveReply(&vpe.WantStatsReply{})
+}
+
+// processCounters processes a counter message received from VPP.
+func processCounters(msg *interfaces.VnetInterfaceCounters) {
+	fmt.Printf("%+v\n", msg)
+
+	if msg.IsCombined == 0 {
+		// simple counter
+		counters, err := ifcounters.DecodeCounters(ifcounters.VnetInterfaceCounters(*msg))
+		if err != nil {
+			fmt.Println("Error:", err)
+		} else {
+			fmt.Printf("%+v\n", counters)
+		}
+	} else {
+		// combined counter
+		counters, err := ifcounters.DecodeCombinedCounters(ifcounters.VnetInterfaceCounters(*msg))
+		if err != nil {
+			fmt.Println("Error:", err)
+		} else {
+			fmt.Printf("%+v\n", counters)
+		}
+	}
+}