Introduce StatsAPI and it's initial implementation

- this implementation is basically Go wrapper around VPP's vppapiclient C library

Change-Id: I6f53dc3e228868834bf3a8a00c686ad05e22f3dd
Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

2 files changed, 75 insertions, 0 deletions

diff --git a/examples/cmd/stats-api/stats_api.go b/examples/cmd/stats-api/stats_api.go
new file mode 100644
index 0000000..74454ab
--- /dev/null
+++ b/examples/cmd/stats-api/stats_api.go
@@ -0,0 +1,66 @@
+// Copyright (c) 2018 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 (
+	"fmt"
+	"log"
+
+	"git.fd.io/govpp.git/adapter"
+	"git.fd.io/govpp.git/adapter/vppapiclient"
+)
+
+// This example shows how to work with VPP's new stats API.
+
+func main() {
+	fmt.Println("Starting VPP stats API example..")
+
+	client := vppapiclient.NewStatClient(vppapiclient.DefaultStatSocket)
+
+	// connect to stats API
+	if err := client.Connect(); err != nil {
+		log.Fatalln("connecting client failed:", err)
+	}
+	defer client.Disconnect()
+
+	// list stats by patterns
+	// you can omit parameters to list all stats
+	list, err := client.ListStats("/if", "/sys")
+	if err != nil {
+		log.Fatalln("listing stats failed:", err)
+	}
+
+	for _, stat := range list {
+		fmt.Printf(" - %v\n", stat)
+	}
+	fmt.Printf("listed %d stats\n", len(list))
+
+	// dump stats by patterns to retrieve stats with the stats data
+	stats, err := client.DumpStats()
+	if err != nil {
+		log.Fatalln("dumping stats failed:", err)
+	}
+
+	for _, stat := range stats {
+		switch data := stat.Data.(type) {
+		case adapter.ErrorStat:
+			if data == 0 {
+				// skip printing errors with 0 value
+				continue
+			}
+		}
+		fmt.Printf(" - %-25s %25v %+v\n", stat.Name, stat.Type, stat.Data)
+	}
+}
diff --git a/examples/cmd/stats-client/stats_client.go b/examples/cmd/stats-client/stats_client.go
index f61f975..7a2c313 100644
--- a/examples/cmd/stats-client/stats_client.go
+++ b/examples/cmd/stats-client/stats_client.go
@@ -28,6 +28,15 @@ import (
 	"git.fd.io/govpp.git/examples/bin_api/stats"
 )
 
+/*
+
+	IMPORTANT NOTICE!
+
+	The binary API module stats used in this example will be deprecated in VPP 19.01.
+	VPP's new stats API should be used, you can find basic usage of new stats API in example stats-api.
+
+*/
+
 func main() {
 	fmt.Println("Starting stats VPP client..")