Update server with nri injection points

This allows development with container to be done for NRI without the need for
custom builds.

This is an experimental feature and is not enabled unless a user has a global
`/etc/nri/conf.json` config setup with plugins on the system.  No NRI code will
be executed if this config file does not exist.

Signed-off-by: Michael Crosby <michael@thepasture.io>

pkg/server/opts.go

@@ -0,0 +1,51 @@
+/*
+   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 server
+
+import (
+	"context"
+
+	"github.com/containerd/containerd"
+	"github.com/containerd/containerd/log"
+	"github.com/containerd/nri"
+	v1 "github.com/containerd/nri/types/v1"
+)
+
+// WithNRISandboxDelete calls delete for a sandbox'd task
+func WithNRISandboxDelete(sandboxID string) containerd.ProcessDeleteOpts {
+	return func(ctx context.Context, p containerd.Process) error {
+		task, ok := p.(containerd.Task)
+		if !ok {
+			return nil
+		}
+		nric, err := nri.New()
+		if err != nil {
+			log.G(ctx).WithError(err).Error("unable to create nri client")
+			return nil
+		}
+		if nric == nil {
+			return nil
+		}
+		sb := &nri.Sandbox{
+			ID: sandboxID,
+		}
+		if _, err := nric.InvokeWithSandbox(ctx, task, v1.Delete, sb); err != nil {
+			log.G(ctx).WithError(err).Errorf("Failed to delete nri for %q", task.ID())
+		}
+		return nil
+	}
+}