Fix issues with plugin and `--live-restore`

Fixes an issue when starting the daemon with live-restore
where previously it was not set, plugins are not running.

Fixes an issue when starting the daemon with live-restore, the plugin
client (for interacting with the plugins HTTP interface) is not set,
causing a panic when the plugin is called.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit cb6633175c0de0a7ae155c4d378cd2379681554b)
Signed-off-by: Victor Vieux <vieux@docker.com>

integration-cli/docker_cli_daemon_plugins_test.go

@@ -145,7 +145,7 @@ func (s *DockerDaemonSuite) TestDaemonShutdownLiveRestoreWithPlugins(c *check.C)
 
 // TestDaemonShutdownWithPlugins shuts down running plugins.
 func (s *DockerDaemonSuite) TestDaemonShutdownWithPlugins(c *check.C) {
-	testRequires(c, IsAmd64, Network)
+	testRequires(c, IsAmd64, Network, SameHostDaemon)
 
 	if err := s.d.Start(); err != nil {
 		c.Fatalf("Could not start daemon: %v", err)
@@ -180,6 +180,11 @@ func (s *DockerDaemonSuite) TestDaemonShutdownWithPlugins(c *check.C) {
 	if out, ec, err := runCommandWithOutput(cmd); ec != 1 {
 		c.Fatalf("Expected exit code '1', got %d err: %v output: %s ", ec, err, out)
 	}
+
+	s.d.Start("--live-restore")
+	cmd = exec.Command("pgrep", "-f", pluginProcessName)
+	out, _, err := runCommandWithOutput(cmd)
+	c.Assert(err, checker.IsNil, check.Commentf(out))
 }
 
 // TestVolumePlugin tests volume creation using a plugin.

plugin/manager_linux.go

@@ -49,6 +49,10 @@ func (pm *Manager) enable(p *v2.Plugin, c *controller, force bool) error {
 		return err
 	}
 
+	return pm.pluginPostStart(p, c)
+}
+
+func (pm *Manager) pluginPostStart(p *v2.Plugin, c *controller) error {
 	client, err := plugins.NewClientWithTimeout("unix://"+filepath.Join(p.GetRuntimeSourcePath(), p.GetSocket()), nil, c.timeoutInSecs)
 	if err != nil {
 		c.restart = false
@@ -59,12 +63,30 @@ func (pm *Manager) enable(p *v2.Plugin, c *controller, force bool) error {
 	p.SetPClient(client)
 	pm.pluginStore.SetState(p, true)
 	pm.pluginStore.CallHandler(p)
-
 	return nil
 }
 
 func (pm *Manager) restore(p *v2.Plugin) error {
-	return pm.containerdClient.Restore(p.GetID(), attachToLog(p.GetID()))
+	if err := pm.containerdClient.Restore(p.GetID(), attachToLog(p.GetID())); err != nil {
+		return err
+	}
+
+	if pm.liveRestore {
+		c := &controller{}
+		if pids, _ := pm.containerdClient.GetPidsForContainer(p.GetID()); len(pids) == 0 {
+			// plugin is not running, so follow normal startup procedure
+			return pm.enable(p, c, true)
+		}
+
+		c.exitChan = make(chan bool)
+		c.restart = true
+		pm.mu.Lock()
+		pm.cMap[p] = c
+		pm.mu.Unlock()
+		return pm.pluginPostStart(p, c)
+	}
+
+	return nil
 }
 
 func shutdownPlugin(p *v2.Plugin, c *controller, containerdClient libcontainerd.Client) {