Merge pull request #1944 from weaveworks/issues/1940-remove-proxy-weaveps-dep

Use netlink instead of shelling out to `weave ps`

proxy/common.go

@@ -3,10 +3,8 @@ package proxy
 import (
 	"bytes"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io/ioutil"
-	"net"
 	"net/http"
 	"os"
 	"os/exec"
@@ -131,35 +129,6 @@ func inspectContainerInPath(client *docker.Client, path string) (*docker.Contain
 	return container, err
 }
 
-func weaveContainerIPs(containerID string) (mac string, ips []net.IP, nets []*net.IPNet, err error) {
-	stdout, stderr, err := callWeave("ps", containerID)
-	if err != nil || len(stderr) > 0 {
-		err = errors.New(string(stderr))
-		return
-	}
-	if len(stdout) <= 0 {
-		return
-	}
-
-	fields := strings.Fields(string(stdout))
-	if len(fields) < 2 {
-		return
-	}
-	mac = fields[1]
-
-	var ip net.IP
-	var ipnet *net.IPNet
-	for _, cidr := range fields[2:] {
-		ip, ipnet, err = net.ParseCIDR(cidr)
-		if err != nil {
-			return
-		}
-		ips = append(ips, ip)
-		nets = append(nets, ipnet)
-	}
-	return
-}
-
 func addVolume(hostConfig jsonObject, source, target, mode string) error {
 	configBinds, err := hostConfig.StringArray("Binds")
 	if err != nil {

proxy/json.go

@@ -1,6 +1,7 @@
 package proxy
 
 import (
+	"encoding/json"
 	"fmt"
 )
 
@@ -45,6 +46,25 @@ func (j jsonObject) String(key string) (string, error) {
 	return result, nil
 }
 
+func (j jsonObject) Int(key string) (int, error) {
+	iface, ok := j[key]
+	if !ok || iface == nil {
+		return 0, nil
+	}
+
+	result, ok := iface.(json.Number)
+	if !ok {
+		return 0, &UnmarshalWrongTypeError{key, "json.Number", iface}
+	}
+
+	i64, err := result.Int64()
+	if err != nil {
+		return 0, err
+	}
+
+	return int(i64), nil
+}
+
 func (j jsonObject) StringArray(key string) ([]string, error) {
 	iface, ok := j[key]
 	if !ok || iface == nil {

proxy/proxy.go

@@ -62,6 +62,7 @@ type Config struct {
 	WithoutDNS          bool
 	NoMulticastRoute    bool
 	DockerHost          string
+	ProcPath            string
 }
 
 type wait struct {
@@ -570,11 +571,21 @@ func (proxy *Proxy) updateContainerNetworkSettings(container jsonObject) error {
 		return err
 	}
 
+	state, err := container.Object("State")
+	if err != nil {
+		return err
+	}
+
+	pid, err := state.Int("Pid")
+	if err != nil {
+		return err
+	}
+
 	if err := proxy.waitForStartByIdent(containerID); err != nil {
 		return err
 	}
-	mac, ips, nets, err := weaveContainerIPs(containerID)
-	if err != nil || len(ips) == 0 {
+	netDevs, err := GetWeaveNetDevs(proxy.ProcPath, pid)
+	if err != nil || len(netDevs) == 0 || len(netDevs[0].CIDRs) == 0 {
 		return err
 	}
 
@@ -582,9 +593,9 @@ func (proxy *Proxy) updateContainerNetworkSettings(container jsonObject) error {
 	if err != nil {
 		return err
 	}
-	networkSettings["MacAddress"] = mac
-	networkSettings["IPAddress"] = ips[0].String()
-	networkSettings["IPPrefixLen"], _ = nets[0].Mask.Size()
+	networkSettings["MacAddress"] = netDevs[0].MAC.String()
+	networkSettings["IPAddress"] = netDevs[0].CIDRs[0].IP.String()
+	networkSettings["IPPrefixLen"], _ = netDevs[0].CIDRs[0].Mask.Size()
 	return nil
 }