CNI IPAM plugin

.gitmodules

@@ -64,3 +64,6 @@
 [submodule "vendor/github.com/hashicorp/go-cleanhttp"]
 	path = vendor/github.com/hashicorp/go-cleanhttp
 	url = http://github.com/hashicorp/go-cleanhttp
+[submodule "vendor/github.com/appc/cni"]
+	path = vendor/github.com/appc/cni
+	url = https://github.com/appc/cni

Makefile

@@ -67,7 +67,7 @@ $(WEAVER_EXE): router/*.go ipam/*.go ipam/*/*.go db/*.go nameserver/*.go prog/we
 $(WEAVEPROXY_EXE): proxy/*.go prog/weaveproxy/*.go
 $(WEAVEUTIL_EXE): prog/weaveutil/*.go
 $(SIGPROXY_EXE): prog/sigproxy/*.go
-$(DOCKERPLUGIN_EXE): prog/plugin/*.go plugin/*/*.go api/*.go common/docker/*.go
+$(DOCKERPLUGIN_EXE): prog/plugin/*.go plugin/*/*.go api/*.go common/*.go common/docker/*.go
 $(TEST_TLS_EXE): test/tls/*.go
 $(WEAVEWAIT_NOOP_EXE): prog/weavewait/*.go
 $(WEAVEWAIT_EXE): prog/weavewait/*.go net/*.go

plugin/ipam/cni.go

@@ -0,0 +1,65 @@
+package ipamplugin
+
+import (
+	"encoding/json"
+	"fmt"
+	"net"
+
+	"github.com/appc/cni/pkg/skel"
+	"github.com/appc/cni/pkg/types"
+)
+
+func (i *Ipam) CmdAdd(args *skel.CmdArgs) error {
+	// extract the things we care about
+	conf, err := loadIPAMConf(args.StdinData)
+	if err != nil {
+		return err
+	}
+	if conf == nil {
+		conf = &ipamConf{}
+	}
+	containerID := args.ContainerID
+	var ipnet *net.IPNet
+
+	if conf.Subnet == "" {
+		ipnet, err = i.weave.AllocateIP(containerID)
+	} else {
+		var subnet *net.IPNet
+		subnet, err = types.ParseCIDR(conf.Subnet)
+		if err != nil {
+			return fmt.Errorf("subnet given in config, but not parseable: %s", err)
+		}
+		ipnet, err = i.weave.AllocateIPInSubnet(containerID, subnet)
+	}
+
+	if err != nil {
+		return err
+	}
+	result := types.Result{
+		IP4: &types.IPConfig{
+			IP:      *ipnet,
+			Gateway: conf.Gateway,
+			Routes:  conf.Routes,
+		},
+	}
+	return result.Print()
+}
+
+func (i *Ipam) CmdDel(args *skel.CmdArgs) error {
+	return i.weave.ReleaseIPsFor(args.ContainerID)
+}
+
+type ipamConf struct {
+	Subnet  string        `json:"subnet,omitempty"`
+	Gateway net.IP        `json:"gateway,omitempty"`
+	Routes  []types.Route `json:"routes"`
+}
+
+type netConf struct {
+	IPAM *ipamConf `json:"ipam"`
+}
+
+func loadIPAMConf(stdinData []byte) (*ipamConf, error) {
+	var conf netConf
+	return conf.IPAM, json.Unmarshal(stdinData, &conf)
+}

prog/plugin/main.go

@@ -9,6 +9,7 @@ import (
 	"os/signal"
 	"syscall"
 
+	cni "github.com/appc/cni/pkg/skel"
 	"github.com/docker/libnetwork/ipamapi"
 	weaveapi "github.com/weaveworks/weave/api"
 	. "github.com/weaveworks/weave/common"
@@ -45,14 +46,20 @@ func main() {
 
 	SetLogLevel(logLevel)
 
+	weave := weaveapi.NewClient(os.Getenv("WEAVE_HTTP_ADDR"), Log)
+
+	if os.Args[0] == "weave-ipam" {
+		i := ipamplugin.NewIpam(weave)
+		cni.PluginMain(i.CmdAdd, i.CmdDel)
+		os.Exit(0)
+	}
+
 	// API 1.21 is the first version that supports docker network commands
 	dockerClient, err := docker.NewVersionedClientFromEnv("1.21")
 	if err != nil {
 		Log.Fatalf("unable to connect to docker: %s", err)
 	}
 
-	weave := weaveapi.NewClient(os.Getenv("WEAVE_HTTP_ADDR"), Log)
-
 	Log.Println("Weave plugin", version, "Command line options:", os.Args[1:])
 	Log.Info(dockerClient.Info())