introspection: add support for deprecations

Deprecation warnings are retrieved from the warning service and
returned via the Server RPC.

Signed-off-by: Samuel Karp <samuelkarp@google.com>

services/introspection/local.go

@@ -18,11 +18,18 @@ package introspection
 
 import (
 	context "context"
+	"errors"
 	"os"
 	"path/filepath"
 	"runtime"
 	"sync"
 
+	"github.com/google/uuid"
+	"google.golang.org/genproto/googleapis/rpc/code"
+	rpc "google.golang.org/genproto/googleapis/rpc/status"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/status"
+
 	api "github.com/containerd/containerd/api/services/introspection/v1"
 	"github.com/containerd/containerd/api/types"
 	"github.com/containerd/containerd/errdefs"
@@ -30,25 +37,42 @@ import (
 	"github.com/containerd/containerd/plugin"
 	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
+	"github.com/containerd/containerd/protobuf"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
-	"github.com/google/uuid"
+	"github.com/containerd/containerd/services/warning"
-	"google.golang.org/genproto/googleapis/rpc/code"
-	rpc "google.golang.org/genproto/googleapis/rpc/status"
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/status"
 )
 
 func init() {
 	registry.Register(&plugin.Registration{
 		Type:     plugins.ServicePlugin,
 		ID:       services.IntrospectionService,
-		Requires: []plugin.Type{},
+		Requires: []plugin.Type{plugins.WarningPlugin},
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
+			sps, err := ic.GetByType(plugins.WarningPlugin)
+			if err != nil {
+				return nil, err
+			}
+			p, ok := sps[plugins.DeprecationsPlugin]
+			if !ok {
+				return nil, errors.New("warning service not found")
+			}
+
+			i, err := p.Instance()
+			if err != nil {
+				return nil, err
+			}
+
+			warningClient, ok := i.(warning.Service)
+			if !ok {
+				return nil, errors.New("could not create a local client for warning service")
+			}
+
 			// this service fetches all plugins through the plugin set of the plugin context
 			return &Local{
 				plugins:       ic.Plugins(),
 				root:          ic.Properties[plugins.PropertyRootDir],
+				warningClient: warningClient,
 			}, nil
 		},
 	})
@@ -60,6 +84,7 @@ type Local struct {
 	root          string
 	plugins       *plugin.Set
 	pluginCache   []*api.Plugin
+	warningClient warning.Service
 }
 
 var _ = (api.IntrospectionClient)(&Local{})
@@ -120,6 +145,7 @@ func (l *Local) Server(ctx context.Context, _ *ptypes.Empty, _ ...grpc.CallOptio
 		UUID:         u,
 		Pid:          uint64(pid),
 		Pidns:        pidns,
+		Deprecations: l.getWarnings(ctx),
 	}, nil
 }
 
@@ -161,6 +187,10 @@ func (l *Local) uuidPath() string {
 	return filepath.Join(l.root, "uuid")
 }
 
+func (l *Local) getWarnings(ctx context.Context) []*api.DeprecationWarning {
+	return warningsPB(ctx, l.warningClient.Warnings())
+}
+
 func adaptPlugin(o interface{}) filters.Adaptor {
 	obj := o.(*api.Plugin)
 	return filters.AdapterFunc(func(fieldpath []string) (string, bool) {
@@ -233,3 +263,16 @@ func pluginsToPB(plugins []*plugin.Plugin) []*api.Plugin {
 
 	return pluginsPB
 }
+
+func warningsPB(ctx context.Context, warnings []warning.Warning) []*api.DeprecationWarning {
+	var pb []*api.DeprecationWarning
+
+	for _, w := range warnings {
+		pb = append(pb, &api.DeprecationWarning{
+			ID:             string(w.ID),
+			Message:        w.Message,
+			LastOccurrence: protobuf.ToTimestamp(w.LastOccurrence),
+		})
+	}
+	return pb
+}