Implement CNI plugin via weaveutil

net/netns.go

@@ -57,12 +57,14 @@ func WithNetNSLinkUnsafe(ns netns.NsHandle, ifName string, work func(link netlin
 	})
 }
 
+var WeaveUtilCmd = "weaveutil"
+
 // A safe version of WithNetNS* which creates a process executing
 // "nsenter --net=<ns-path> weaveutil <cmd> [args]".
 func WithNetNS(nsPath string, cmd string, args ...string) ([]byte, error) {
 	var stdout, stderr bytes.Buffer
 
-	args = append([]string{"--net=" + nsPath, "weaveutil", cmd}, args...)
+	args = append([]string{"--net=" + nsPath, WeaveUtilCmd, cmd}, args...)
 	c := exec.Command("nsenter", args...)
 	c.Stdout = &stdout
 	c.Stderr = &stderr

prog/weaveutil/cni.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"os"
+
+	cni "github.com/appc/cni/pkg/skel"
+
+	weaveapi "github.com/weaveworks/weave/api"
+	"github.com/weaveworks/weave/common"
+	ipamplugin "github.com/weaveworks/weave/plugin/ipam"
+	netplugin "github.com/weaveworks/weave/plugin/net"
+)
+
+func cniNet(args []string) error {
+	weave := weaveapi.NewClient(os.Getenv("WEAVE_HTTP_ADDR"), common.Log)
+	n := netplugin.NewCNIPlugin(weave)
+	cni.PluginMain(n.CmdAdd, n.CmdDel)
+	return nil
+}
+
+func cniIPAM(args []string) error {
+	weave := weaveapi.NewClient(os.Getenv("WEAVE_HTTP_ADDR"), common.Log)
+	i := ipamplugin.NewIpam(weave)
+	cni.PluginMain(i.CmdAdd, i.CmdDel)
+	return nil
+}

prog/weaveutil/main.go

@@ -4,6 +4,10 @@ package main
 import (
 	"fmt"
 	"os"
+	"path/filepath"
+	"strings"
+
+	weavenet "github.com/weaveworks/weave/net"
 )
 
 var commands map[string]func([]string) error
@@ -28,10 +32,30 @@ func init() {
 		"del-iface":              delIface,
 		"setup-iface":            setupIface,
 		"list-netdevs":           listNetDevs,
+		"cni-net":                cniNet,
+		"cni-ipam":               cniIPAM,
 	}
 }
 
 func main() {
+	// force re-exec of this binary
+	selfPath, err := filepath.EvalSymlinks("/proc/self/exe")
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	weavenet.WeaveUtilCmd = selfPath
+
+	// If no args passed, act as CNI plugin based on executable name
+	switch {
+	case len(os.Args) == 1 && strings.HasSuffix(os.Args[0], "weave-ipam"):
+		cniIPAM(os.Args)
+		os.Exit(0)
+	case len(os.Args) == 1 && strings.HasSuffix(os.Args[0], "weave-net"):
+		cniNet(os.Args)
+		os.Exit(0)
+	}
+
 	if len(os.Args) < 2 {
 		usage()
 		os.Exit(1)

weave

@@ -1036,7 +1036,7 @@ docker run --rm $(docker_run_options) --pid=host -i \\
  -e CNI_VERSION -e CNI_COMMAND -e CNI_CONTAINERID -e CNI_NETNS \\
  -e CNI_IFNAME -e CNI_ARGS -e CNI_PATH \\
  -v /etc/cni:/etc/cni -v /opt/cni:/opt/cni \$EXTRA_VOLUMES \\
- $PLUGIN_IMAGE $COVERAGE_ARGS $2
+--entrypoint=/usr/bin/weaveutil $EXEC_IMAGE $2
 EOF
     chmod a+x "$1"
 }
@@ -1052,8 +1052,8 @@ EOF
 
 setup_cni() {
     if [ -d $HOST_ROOT/opt/cni/bin ] ; then
-        create_cni_script $HOST_ROOT/opt/cni/bin/weave-net  --cni-net
-        create_cni_script $HOST_ROOT/opt/cni/bin/weave-ipam --cni-ipam
+        create_cni_script $HOST_ROOT/opt/cni/bin/weave-net  cni-net
+        create_cni_script $HOST_ROOT/opt/cni/bin/weave-ipam cni-ipam
     fi
     if [ -d $HOST_ROOT/etc/cni/net.d -a ! -f $HOST_ROOT/etc/cni/net.d/10-weave.conf ] ; then
         create_cni_config $HOST_ROOT/etc/cni/net.d/10-weave.conf