introspection: expose the daemon's PID and PIDNS

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

cmd/ctr/app/main.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/cmd/ctr/commands/content"
 	"github.com/containerd/containerd/cmd/ctr/commands/events"
 	"github.com/containerd/containerd/cmd/ctr/commands/images"
+	"github.com/containerd/containerd/cmd/ctr/commands/info"
 	"github.com/containerd/containerd/cmd/ctr/commands/install"
 	"github.com/containerd/containerd/cmd/ctr/commands/leases"
 	namespacesCmd "github.com/containerd/containerd/cmd/ctr/commands/namespaces"
@@ -116,6 +117,7 @@ containerd CLI
 		install.Command,
 		ociCmd.Command,
 		sandboxes.Command,
+		info.Command,
 	}, extraCmds...)
 	app.Before = func(context *cli.Context) error {
 		if context.GlobalBool("debug") {

cmd/ctr/commands/info/info.go

@@ -0,0 +1,48 @@
+/*
+   Copyright The containerd Authors.
+
+   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 info
+
+import (
+	api "github.com/containerd/containerd/api/services/introspection/v1"
+	"github.com/containerd/containerd/cmd/ctr/commands"
+	ptypes "github.com/containerd/containerd/protobuf/types"
+	"github.com/urfave/cli"
+)
+
+type Info struct {
+	Server *api.ServerResponse `json:"server"`
+}
+
+// Command is a cli command to output the containerd server info
+var Command = cli.Command{
+	Name:  "info",
+	Usage: "print the server info",
+	Action: func(context *cli.Context) error {
+		client, ctx, cancel, err := commands.NewClient(context)
+		if err != nil {
+			return err
+		}
+		defer cancel()
+		var info Info
+		info.Server, err = client.IntrospectionService().Server(ctx, &ptypes.Empty{})
+		if err != nil {
+			return err
+		}
+		commands.PrintAsJSON(info)
+		return nil
+	},
+}