restart plugin: support binary log uri

Introduce LogURIGenerator helper function in cio package. It is used in
the restart options, like WithBinaryLogURI and WithFileLogURI.

And restart.LogPathLabel might be used in production and work well. In
order to reduce breaking change, the LogPathLabel is still recognized if
new LogURILabel is not set. In next release 1.5, the LogPathLabel will
be removed.

Signed-off-by: Wei Fu <fuweid89@gmail.com>

runtime/restart/monitor/change.go

@@ -18,10 +18,13 @@ package monitor
 
 import (
 	"context"
+	"net/url"
 	"syscall"
 
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/cio"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 )
 
 type stopChange struct {
@@ -34,14 +37,30 @@ func (s *stopChange) apply(ctx context.Context, client *containerd.Client) error
 
 type startChange struct {
 	container containerd.Container
-	logPath   string
+	logURI    string
+
+	// Deprecated(in release 1.5): but recognized now, prefer to use logURI
+	logPath string
 }
 
 func (s *startChange) apply(ctx context.Context, client *containerd.Client) error {
 	log := cio.NullIO
-	if s.logPath != "" {
+
+	if s.logURI != "" {
+		uri, err := url.Parse(s.logURI)
+		if err != nil {
+			return errors.Wrapf(err, "failed to parse %v into url", s.logURI)
+		}
+		log = cio.LogURI(uri)
+	} else if s.logPath != "" {
 		log = cio.LogFile(s.logPath)
 	}
+
+	if s.logURI != "" && s.logPath != "" {
+		logrus.Warnf("LogPathLabel=%v has been deprecated, using LogURILabel=%v",
+			s.logPath, s.logURI)
+	}
+
 	killTask(ctx, s.container)
 	task, err := s.container.NewTask(ctx, log)
 	if err != nil {

runtime/restart/monitor/monitor.go

@@ -200,6 +200,7 @@ func (m *monitor) monitor(ctx context.Context) ([]change, error) {
 			changes = append(changes, &startChange{
 				container: c,
 				logPath:   labels[restart.LogPathLabel],
+				logURI:    labels[restart.LogURILabel],
 			})
 		case containerd.Stopped:
 			changes = append(changes, &stopChange{