adds the spec required state command

Signed-off-by: Mike Brown <brownwm@us.ibm.com>

main.go

@@ -79,6 +79,7 @@ func main() {
 		resumeCommand,
 		specCommand,
 		startCommand,
+		stateCommand,
 	}
 	app.Before = func(context *cli.Context) error {
 		if context.GlobalBool("debug") {

state.go

@@ -0,0 +1,69 @@
+// +build linux
+
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"time"
+
+	"github.com/codegangsta/cli"
+)
+
+// cState represents the platform agnostic pieces relating to a running
+// container's status and state.  Note: The fields in this structure adhere to
+// the opencontainers/specs requirement for json fields that must be returned
+// in a state command.
+type cState struct {
+	// Version is the OCI version for the container
+	Version string `json:"ociVersion"`
+	// ID is the container ID
+	ID string `json:"id"`
+	// InitProcessPid is the init process id in the parent namespace
+	InitProcessPid int `json:"pid"`
+	// Bundle is the path on the filesystem to the bundle
+	Bundle string `json:"bundlePath"`
+	// Rootfs is a path to a directory containing the container's root filesystem.
+	Rootfs string `json:"rootfsPath"`
+	// Status is the current status of the container, running, paused, ...
+	Status string `json:"status"`
+	// Created is the unix timestamp for the creation time of the container in UTC
+	Created time.Time `json:"created"`
+}
+
+var stateCommand = cli.Command{
+	Name:  "state",
+	Usage: "output the state of a container",
+	ArgsUsage: `<container-id>
+
+Where "<container-id>" is your name for the instance of the container.`,
+	Description: `The state command outputs current state information for the
+instance of a container.`,
+	Action: func(context *cli.Context) {
+		container, err := getContainer(context)
+		if err != nil {
+			fatal(err)
+		}
+		containerStatus, err := container.Status()
+		if err != nil {
+			fatal(err)
+		}
+		state, err := container.State()
+		if err != nil {
+			fatal(err)
+		}
+		cs := cState{
+			Version:        state.BaseState.Config.Version,
+			ID:             state.BaseState.ID,
+			InitProcessPid: state.BaseState.InitProcessPid,
+			Status:         containerStatus.String(),
+			Bundle:         searchLabels(state.Config.Labels, "bundle"),
+			Rootfs:         state.BaseState.Config.Rootfs,
+			Created:        state.BaseState.Created}
+		data, err := json.MarshalIndent(cs, "", "  ")
+		if err != nil {
+			fatal(err)
+		}
+		os.Stdout.Write(data)
+	},
+}