cli: add a command to monitor changes of best paths

$ gobgp monitor global rib
[ROUTE] 10.0.1.0/24 via 192.168.10.3 aspath [65001] attrs [{Origin: IGP} {Med: 0}]
[ROUTE] 10.0.2.0/24 via 192.168.10.4 aspath [65002] attrs [{Origin: IGP} {Med: 0}]
[ROUTE] 10.0.3.0/24 via 192.168.10.5 aspath [65003] attrs [{Origin: IGP} {Med: 0}]
[ROUTE] 10.0.4.0/24 via 192.168.10.6 aspath [65004] attrs [{Origin: IGP} {Med: 0}]
[DELROUTE] 10.0.4.0/24 via 192.168.10.6 aspath [65004] attrs [{Origin: IGP} {Med: 0}]
[DELROUTE] 10.0.2.0/24 via 192.168.10.4 aspath [65002] attrs [{Origin: IGP} {Med: 0}]
[DELROUTE] 10.0.3.0/24 via 192.168.10.5 aspath [65003] attrs [{Origin: IGP} {Med: 0}]
[ROUTE] 10.0.3.0/24 via 192.168.10.5 aspath [65003] attrs [{Origin: IGP} {Med: 100}]
[ROUTE] 10.0.6.0/24 via 192.168.10.5 aspath [65003 65005] attrs [{Origin: IGP} {Med: 100}]
[ROUTE] 10.0.2.0/24 via 192.168.10.4 aspath [65002] attrs [{Origin: IGP} {Med: 200}]

Signed-off-by: ISHIDA Wataru <ishida.wataru@lab.ntt.co.jp>

5 files changed, 88 insertions, 7 deletions

diff --git a/gobgp/common.go b/gobgp/common.go
index d7d9e2c4..0ae61af7 100644
--- a/gobgp/common.go
+++ b/gobgp/common.go
@@ -52,6 +52,7 @@ const (
 	CMD_ACTIONS        = "actions"
 	CMD_IMPORT         = "import"
 	CMD_EXPORT         = "export"
+	CMD_MONITOR        = "monitor"
 )
 
 var subOpts struct {
diff --git a/gobgp/global.go b/gobgp/global.go
index b5f19ad3..93bd1fde 100644
--- a/gobgp/global.go
+++ b/gobgp/global.go
@@ -70,7 +70,7 @@ func showGlobalRib() error {
 
 	sort.Sort(ps)
 
-	showRoute(ps, true, true)
+	showRoute(ps, true, true, false)
 	return nil
 }
 
diff --git a/gobgp/main.go b/gobgp/main.go
index ba6c8d5f..79629380 100644
--- a/gobgp/main.go
+++ b/gobgp/main.go
@@ -58,9 +58,10 @@ func main() {
 	globalCmd := NewGlobalCmd()
 	neighborCmd := NewNeighborCmd()
 	policyCmd := NewPolicyCmd()
+	monitorCmd := NewMonitorCmd()
 	rootCmd.AddCommand(globalCmd)
 	rootCmd.AddCommand(neighborCmd)
 	rootCmd.AddCommand(policyCmd)
-
+	rootCmd.AddCommand(monitorCmd)
 	rootCmd.Execute()
 }
diff --git a/gobgp/monitor.go b/gobgp/monitor.go
new file mode 100644
index 00000000..b57b1451
--- /dev/null
+++ b/gobgp/monitor.go
@@ -0,0 +1,72 @@
+// Copyright (C) 2015 Nippon Telegraph and Telephone Corporation.
+//
+// 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"
+	"github.com/osrg/gobgp/api"
+	"github.com/spf13/cobra"
+	"golang.org/x/net/context"
+	"io"
+	"net"
+	"os"
+)
+
+func NewMonitorCmd() *cobra.Command {
+	ribCmd := &cobra.Command{
+		Use: CMD_RIB,
+		Run: func(cmd *cobra.Command, args []string) {
+			rt, err := checkAddressFamily(net.IP{})
+			if err != nil {
+				fmt.Println(err)
+				os.Exit(1)
+			}
+			arg := &api.Arguments{
+				Resource: api.Resource_GLOBAL,
+				Af:       rt,
+			}
+
+			stream, err := client.MonitorBestChanged(context.Background(), arg)
+			if err != nil {
+				fmt.Println(err)
+				os.Exit(1)
+			}
+			for {
+				p, err := stream.Recv()
+				if err == io.EOF {
+					break
+				} else if err != nil {
+					fmt.Println(err)
+					os.Exit(1)
+				}
+				showRoute([]*api.Path{p}, false, false, true)
+			}
+
+		},
+	}
+
+	globalCmd := &cobra.Command{
+		Use: CMD_GLOBAL,
+	}
+	globalCmd.AddCommand(ribCmd)
+
+	monitorCmd := &cobra.Command{
+		Use: CMD_MONITOR,
+	}
+	monitorCmd.AddCommand(globalCmd)
+
+	return monitorCmd
+}
diff --git a/gobgp/neighbor.go b/gobgp/neighbor.go
index 8d311f9b..c478f7a1 100644
--- a/gobgp/neighbor.go
+++ b/gobgp/neighbor.go
@@ -223,7 +223,7 @@ type AsPathFormat struct {
 	separator string
 }
 
-func showRoute(pathList []*api.Path, showAge bool, showBest bool) {
+func showRoute(pathList []*api.Path, showAge bool, showBest bool, isMonitor bool) {
 
 	var pathStrs [][]interface{}
 	maxPrefixLen := len("Network")
@@ -352,8 +352,13 @@ func showRoute(pathList []*api.Path, showAge bool, showBest bool) {
 		if maxAsPathLen < len(aspath(p.Attrs)) {
 			maxAsPathLen = len(aspath(p.Attrs))
 		}
-
-		if showAge {
+		if isMonitor {
+			title := "ROUTE"
+			if p.IsWithdraw {
+				title = "DELROUTE"
+			}
+			pathStrs = append(pathStrs, []interface{}{title, p.Nlri.Prefix, p.Nexthop, aspath(p.Attrs), formatAttrs(p.Attrs)})
+		} else if showAge {
 			pathStrs = append(pathStrs, []interface{}{best, p.Nlri.Prefix, p.Nexthop, aspath(p.Attrs), formatTimedelta(p.Age), formatAttrs(p.Attrs)})
 		} else {
 			pathStrs = append(pathStrs, []interface{}{best, p.Nlri.Prefix, p.Nexthop, aspath(p.Attrs), formatAttrs(p.Attrs)})
@@ -361,7 +366,9 @@ func showRoute(pathList []*api.Path, showAge bool, showBest bool) {
 	}
 
 	var format string
-	if showAge {
+	if isMonitor {
+		format = "[%s] %s via %s aspath [%s] attrs %s\n"
+	} else if showAge {
 		format = fmt.Sprintf("%%-2s %%-%ds %%-%ds %%-%ds %%-10s %%-s\n", maxPrefixLen, maxNexthopLen, maxAsPathLen)
 		fmt.Printf(format, "", "Network", "Next Hop", "AS_PATH", "Age", "Attrs")
 	} else {
@@ -455,7 +462,7 @@ func showNeighborRib(r string, remoteIP net.IP) error {
 	}
 
 	sort.Sort(ps)
-	showRoute(ps, showAge, showBest)
+	showRoute(ps, showAge, showBest, false)
 	return nil
 }