From 900ff9f4c24f015c7ea9b7a8b883fe9b61de4c3d Mon Sep 17 00:00:00 2001
From: Daniel Czerwonk <daniel@dan-nrw.de>
Date: Mon, 19 Jun 2017 21:04:09 +0200
Subject: [PATCH] removed bird client dependency, using socket instead

---
 bird_client.go | 70 ++++++++++++++++++++++++++++++++++++++++++--------
 main.go        |  5 ++--
 2 files changed, 63 insertions(+), 12 deletions(-)

diff --git a/bird_client.go b/bird_client.go
index 2a82c16..de642fc 100644
--- a/bird_client.go
+++ b/bird_client.go
@@ -1,16 +1,30 @@
 package main
 
 import (
-	"os/exec"
+	"net"
+
+	"regexp"
+
+	"time"
 
 	"github.com/czerwonk/bird_exporter/protocol"
+	"github.com/prometheus/common/log"
 )
 
+const bufferSize = 4096
+const timeout = 30
+
+var birdReturnCodeRegex *regexp.Regexp
+
+func init() {
+	birdReturnCodeRegex = regexp.MustCompile("\\d{4} \n$")
+}
+
 func getProtocols() ([]*protocol.Protocol, error) {
 	protocols := make([]*protocol.Protocol, 0)
 
 	if *birdEnabled {
-		s, err := getProtocolsFromBird(4)
+		s, err := getProtocolsFromBird(*birdSocket, 4)
 		if err != nil {
 			return nil, err
 		}
@@ -18,7 +32,7 @@ func getProtocols() ([]*protocol.Protocol, error) {
 	}
 
 	if *bird6Enabled {
-		s, err := getProtocolsFromBird(6)
+		s, err := getProtocolsFromBird(*bird6Socket, 6)
 		if err != nil {
 			return nil, err
 		}
@@ -28,14 +42,28 @@ func getProtocols() ([]*protocol.Protocol, error) {
 	return protocols, nil
 }
 
-func getProtocolsFromBird(ipVersion int) ([]*protocol.Protocol, error) {
-	client := *birdClient
+func getProtocolsFromBird(socketPath string, ipVersion int) ([]*protocol.Protocol, error) {
+	conn, err := net.Dial("unix", socketPath)
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
 
-	if ipVersion == 6 {
-		client += "6"
+	conn.SetReadDeadline(time.Now().Add(timeout * time.Second))
+
+	buf := make([]byte, bufferSize)
+	n, err := conn.Read(buf[:])
+	if err != nil {
+		return nil, err
+	}
+	log.Debug(string(buf[:n]))
+
+	_, err = conn.Write([]byte("show protocols all\n"))
+	if err != nil {
+		return nil, err
 	}
 
-	output, err := getBirdOutput(client)
+	output, err := readFromSocket(conn)
 	if err != nil {
 		return nil, err
 	}
@@ -43,6 +71,28 @@ func getProtocolsFromBird(ipVersion int) ([]*protocol.Protocol, error) {
 	return parseOutput(output, ipVersion), nil
 }
 
-func getBirdOutput(birdClient string) ([]byte, error) {
-	return exec.Command(birdClient, "show", "protocols", "all").Output()
+func readFromSocket(conn net.Conn) ([]byte, error) {
+	b := make([]byte, 0)
+	buf := make([]byte, bufferSize)
+
+	done := false
+	for !done {
+		n, err := conn.Read(buf[:])
+		if err != nil {
+			return nil, err
+		}
+
+		b = append(b, buf[:n]...)
+		done = endsWithBirdReturnCode(b)
+	}
+
+	return b, nil
+}
+
+func endsWithBirdReturnCode(b []byte) bool {
+	if len(b) < 6 {
+		return false
+	}
+
+	return birdReturnCodeRegex.Match(b[len(b)-6:])
 }
diff --git a/main.go b/main.go
index 8d3955b..80dd21f 100644
--- a/main.go
+++ b/main.go
@@ -11,13 +11,14 @@ import (
 	"github.com/prometheus/common/log"
 )
 
-const version string = "0.7.1"
+const version string = "0.8.0"
 
 var (
 	showVersion   = flag.Bool("version", false, "Print version information.")
 	listenAddress = flag.String("web.listen-address", ":9324", "Address on which to expose metrics and web interface.")
 	metricsPath   = flag.String("web.telemetry-path", "/metrics", "Path under which to expose metrics.")
-	birdClient    = flag.String("bird.client", "birdc", "Binary to communicate with the bird routing daemon")
+	birdSocket    = flag.String("bird.socket", "/var/run/bird.ctl", "Socket to communicate with bird routing daemon")
+	bird6Socket   = flag.String("bird.socket6", "/var/run/bird6.ctl", "Socket to communicate with bird6 routing daemon")
 	birdEnabled   = flag.Bool("bird.ipv4", true, "Get protocols from bird")
 	bird6Enabled  = flag.Bool("bird.ipv6", true, "Get protocols from bird6")
 )