net: rkt list supports displaying container's IP addrs

Fixes #593

networking/netinfo/netinfo.go

@@ -0,0 +1,53 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// 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 netinfo
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+const filename = "net-info.json"
+
+type NetInfo struct {
+	NetName string `json:"netName"`
+	IfName  string `json:"ifName"`
+	IP      string `json:"ip"`
+}
+
+func LoadAt(cdirfd int) ([]NetInfo, error) {
+	fd, err := syscall.Openat(cdirfd, filename, syscall.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	f := os.NewFile(uintptr(fd), filename)
+
+	info := []NetInfo{}
+	err = json.NewDecoder(f).Decode(&info)
+	return info, err
+}
+
+func Save(root string, info []NetInfo) error {
+	f, err := os.Create(filepath.Join(root, filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	return json.NewEncoder(f).Encode(info)
+}

networking/networking.go

@@ -26,6 +26,7 @@ import (
 	"github.com/coreos/rocket/Godeps/_workspace/src/github.com/appc/spec/schema/types"
 	"github.com/coreos/rocket/Godeps/_workspace/src/github.com/vishvananda/netlink"
 
+	"github.com/coreos/rocket/networking/netinfo"
 	"github.com/coreos/rocket/networking/util"
 )
 
@@ -105,6 +106,10 @@ func Setup(rktRoot string, contID types.UUID) (*Networking, error) {
 		return nil, fmt.Errorf("no nets successfully setup")
 	}
 
+	if err = n.saveNetInfo(); err != nil {
+		return nil, err
+	}
+
 	// last net is the default
 	n.MetadataIP = n.nets[len(n.nets)-1].ip
 
@@ -228,6 +233,22 @@ func (e *containerEnv) teardownNets(netns string, nets []activeNet) {
 	}
 }
 
+// saveNetInfo writes out the info about active nets
+// for "rkt list" and friends to display
+func (e *Networking) saveNetInfo() error {
+	nis := []netinfo.NetInfo{}
+	for _, n := range e.nets {
+		ni := netinfo.NetInfo{
+			NetName: n.Name,
+			IfName:  n.ifName,
+			IP:      n.ip.String(),
+		}
+		nis = append(nis, ni)
+	}
+
+	return netinfo.Save(e.rktRoot, nis)
+}
+
 func newNetNS() (hostNS, childNS *os.File, err error) {
 	defer func() {
 		if err != nil {

rkt/containers.go

@@ -28,6 +28,7 @@ import (
 	"github.com/coreos/rocket/Godeps/_workspace/src/code.google.com/p/go-uuid/uuid"
 	"github.com/coreos/rocket/Godeps/_workspace/src/github.com/appc/spec/schema/types"
 	"github.com/coreos/rocket/common"
+	"github.com/coreos/rocket/networking/netinfo"
 	"github.com/coreos/rocket/pkg/lock"
 )
 
@@ -36,7 +37,8 @@ import (
 type container struct {
 	*lock.DirLock
 	uuid        *types.UUID
-	createdByMe bool // true if we're the creator of this container (only the creator can xToPrepare or xToRun directly from preparing)
+	createdByMe bool              // true if we're the creator of this container (only the creator can xToPrepare or xToRun directly from preparing)
+	nets        []netinfo.NetInfo // list of networks (name, IP, iface) this container is using
 
 	isEmbryo         bool // directory starts as embryo before entering preparing state, serves as stage for acquiring lock before rename to prepare/.
 	isPreparing      bool // when locked at containers/prepare/$uuid the container is actively being prepared
@@ -248,6 +250,18 @@ func getContainer(uuid string) (*container, error) {
 
 	c.DirLock = l
 
+	if c.isRunning() {
+		cfd, err := c.Fd()
+		if err != nil {
+			return nil, fmt.Errorf("error acquiring container %v dir fd: %v", uuid, err)
+		}
+		c.nets, err = netinfo.LoadAt(cfd)
+		// ENOENT is ok -- assume running without --private-net
+		if err != nil && !os.IsNotExist(err) {
+			return nil, fmt.Errorf("error opening container %v netinfo: %v", uuid, err)
+		}
+	}
+
 	return c, nil
 }
 

rkt/list.go

@@ -18,9 +18,11 @@ package main
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/coreos/rocket/Godeps/_workspace/src/github.com/appc/spec/schema"
 	common "github.com/coreos/rocket/common"
+	"github.com/coreos/rocket/networking/netinfo"
 )
 
 var (
@@ -40,7 +42,7 @@ func init() {
 
 func runList(args []string) (exit int) {
 	if !flagNoLegend {
-		fmt.Fprintf(tabOut, "UUID\tACI\tSTATE\n")
+		fmt.Fprintf(tabOut, "UUID\tACI\tSTATE\tNETWORKS\n")
 	}
 
 	if err := walkContainers(includeMostDirs, func(c *container) {
@@ -68,7 +70,7 @@ func runList(args []string) (exit int) {
 			app_zero = m.Apps[0].Name.String()
 		}
 
-		fmt.Fprintf(tabOut, "%s\t%s\t%s\n", c.uuid, app_zero, c.getState())
+		fmt.Fprintf(tabOut, "%s\t%s\t%s\t%s\n", c.uuid, app_zero, c.getState(), fmtNets(c.nets))
 		for i := 1; i < len(m.Apps); i++ {
 			fmt.Fprintf(tabOut, "\t%s\n", m.Apps[i].Name.String())
 		}
@@ -80,3 +82,12 @@ func runList(args []string) (exit int) {
 	tabOut.Flush()
 	return 0
 }
+
+func fmtNets(nis []netinfo.NetInfo) string {
+	parts := []string{}
+	for _, ni := range nis {
+		// there will be IPv6 support soon so distinguish between v4 and v6
+		parts = append(parts, fmt.Sprintf("%v:ip4=%v", ni.NetName, ni.IP))
+	}
+	return strings.Join(parts, ", ")
+}

rkt/status.go

@@ -74,6 +74,10 @@ func runStatus(args []string) (exit int) {
 func printStatus(c *container) error {
 	stdout("state=%s", c.getState())
 
+	if c.isRunning() {
+		stdout("networks=%s", fmtNets(c.nets))
+	}
+
 	if !c.isEmbryo && !c.isPreparing && !c.isPrepared && !c.isAbortedPrepare && !c.isGarbage && !c.isGone {
 		pid, err := c.getPID()
 		if err != nil {