Add generic shutdown handling in manager and plugin

cli/manager.go

@@ -6,7 +6,6 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
-	"sync"
 	"syscall"
 
 	"github.com/sirupsen/logrus"
@@ -24,6 +23,9 @@ type Config struct {
 	RootDir      string   `toml:"root_path"`
 	PluginDir    string   `toml:"plugin_path"`
 	ExtraPlugins []string `toml:"extra_plugins"`
+
+	// Specify additional plugins that are a part of the main executable.
+	LinkedPlugins []plugin.Initializer
 }
 
 type Manager struct {
@@ -31,7 +33,7 @@ type Manager struct {
 
 	Config
 
-	sig chan os.Signal
+	stop chan os.Signal
 }
 
 func NewManager(rootDir string, extraPlugins ...string) (*Manager, error) {
@@ -57,11 +59,20 @@ func NewManager(rootDir string, extraPlugins ...string) (*Manager, error) {
 	}
 	return &Manager{
 		plugins: m,
-		sig:     make(chan os.Signal, 10),
+		stop:     make(chan os.Signal, 10),
 		Config:  conf,
 	}, nil
 }
 
+func (manager *Manager) Stop() {
+	select {
+	case <-manager.stop:
+		// already stopped
+	default:
+		close(manager.stop)
+	}
+}
+
 func (manager *Manager) Plugins() *plugin.Manager {
 	return manager.plugins
 }
@@ -84,6 +95,9 @@ func (manager *Manager) Start() error {
 		}
 		m.Register(plugin.InitializeFromFile(pl))
 	}
+	for _, pl := range manager.LinkedPlugins {
+		m.Register(pl)
+	}
 	if err := configure(m); err != nil {
 		return errors.Wrap(err, "unable to init extra plugins")
 	}
@@ -110,9 +124,15 @@ func (manager *Manager) Start() error {
 func (manager *Manager) Loop() error {
 	st := make(chan os.Signal, 10)
 	signal.Notify(st, syscall.SIGHUP, syscall.SIGUSR1, syscall.SIGUSR2)
-	signal.Notify(manager.sig, os.Interrupt, syscall.SIGTERM)
+	signal.Notify(st, os.Interrupt, syscall.SIGTERM)
 	for {
 		select {
+		case <-manager.stop:
+			logrus.Infoln("shutting down")
+			if err := manager.Shutdown(); err != nil {
+				logrus.Warnln("error shutting down:", err)
+			}
+			return nil
 		case s := <-st:
 			switch s {
 			case syscall.SIGHUP:
@@ -130,46 +150,20 @@ func (manager *Manager) Loop() error {
 					logrus.Warnln("unable to restart js vm:", err)
 					continue
 				}
+			case os.Interrupt:
+				fallthrough
+			case syscall.SIGTERM:
+				manager.Stop()
 			default:
 				logrus.Infoln("received signal", s, "but not doing anything with it")
 			}
-
-		case <-manager.sig:
-			logrus.Infoln("shutting down")
-			if err := manager.Shutdown(); err != nil {
-				logrus.Warnln("error shutting down:", err)
-			}
-			return nil
 		}
 	}
 }
 
 func (manager *Manager) Shutdown() error {
 	m := manager.plugins
-
-	wg := &sync.WaitGroup{}
-	wg.Add(1)
-	go func() {
-		myVM, err := vm.FromPlugins(m)
-		if err != nil {
-			logrus.Warnln("error shutting down vm:", err)
-		}
-
-		if err := myVM.Shutdown(); err != nil {
-			logrus.Warnln("error shutting down vm:", err)
-		}
-		wg.Done()
-	}()
-	wg.Add(1)
-	go func() {
-		d, err := event.FromPlugins(m)
-		if err != nil {
-			logrus.Warnln("error shutting down events:", err)
-		}
-		d.Stop()
-		wg.Done()
-	}()
-	wg.Wait()
+	m.Shutdown()
 	return nil
 }
 

config/plugin.go

@@ -28,7 +28,6 @@ func ConfigurePlugin(m *plugin.Manager, opts ...SetupOption) error {
 
 func Initialize(m *plugin.Manager) (plugin.Plugin, error) {
 	p := &configPlugin{}
-	m.OnPluginInit(p)
 	return p, nil
 }
 

event/plugin.go

@@ -20,7 +20,6 @@ func FromPlugins(m *plugin.Manager) (*Dispatcher, error) {
 
 func Initialize(m *plugin.Manager) (plugin.Plugin, error) {
 	p := &eventPlugin{NewDispatcher()}
-	m.OnPluginInit(p)
 	return p, nil
 }
 
@@ -35,3 +34,7 @@ func (p *eventPlugin) Name() string {
 func (p *eventPlugin) HandlePluginInit(o plugin.Plugin) {
 	p.dispatcher.Emit("plugin.INIT", map[string]interface{}{"name": o.Name(), "plugin": o})
 }
+
+func (p *eventPlugin) HandleShutdown() {
+	p.dispatcher.Stop()
+}

irc/irc.go

@@ -100,7 +100,17 @@ func (conn *Connection) controlLoop() {
 }
 
 func NewManager(c *Config, ev *event.Dispatcher) *Manager {
-	return &Manager{config: c, events: ev}
+	m := &Manager{config: c, events: ev}
+	if c.AutoConnect {
+		go func() {
+			logrus.Infoln("Automatically connecting...")
+			<-time.After(250 * time.Millisecond)
+			if err := m.Connect(); err != nil {
+				logrus.Errorln("failed to autoconnect:", err)
+			}
+		}()
+	}
+	return m
 }
 
 func (m *Manager) Do(fn func(*Connection) error) error {

plugin/plugin.go

@@ -16,6 +16,10 @@ type InitHandler interface {
 	HandlePluginInit(Plugin)
 }
 
+type ShutdownHandler interface {
+	HandleShutdown()
+}
+
 type Initializer interface {
 	Initialize(*Manager) (Plugin, error)
 }
@@ -54,7 +58,8 @@ type Manager struct {
 
 	loaded map[string]Plugin
 
-	onInit []InitHandler
+	onInit     []InitHandler
+	onShutdown []ShutdownHandler
 
 	mu sync.RWMutex
 }
@@ -76,6 +81,28 @@ func (m *Manager) OnPluginInit(h InitHandler) {
 	m.onInit = append(m.onInit, h)
 }
 
+func (m *Manager) OnShutdown(h ShutdownHandler) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.onShutdown = append(m.onShutdown, h)
+}
+
+func (m *Manager) Shutdown() {
+	m.mu.RLock()
+	hs := make([]ShutdownHandler, len(m.onShutdown))
+	copy(hs, m.onShutdown)
+	m.mu.RUnlock()
+	wg := &sync.WaitGroup{}
+	for _, h := range m.onShutdown {
+		wg.Add(1)
+		go func(sh ShutdownHandler) {
+			sh.HandleShutdown()
+			wg.Done()
+		}(h)
+	}
+	wg.Wait()
+}
+
 func (m *Manager) Lookup(name string) (Plugin, error) {
 	m.mu.RLock()
 	defer m.mu.RUnlock()
@@ -126,6 +153,12 @@ func (m *Manager) Configure() []error {
 		if !ok {
 			// not already loaded, add it
 			m.loaded[pn] = plg
+			if ih, ok := plg.(InitHandler); ok {
+				m.onInit = append(m.onInit, ih)
+			}
+			if sh, ok := plg.(ShutdownHandler); ok {
+				m.onShutdown = append(m.onShutdown, sh)
+			}
 		}
 		// unlock outside of any conditional
 		m.mu.Unlock()

vm/plugin.go

@@ -36,7 +36,6 @@ func FromPlugins(m *plugin.Manager) (*VM, error) {
 
 func Initialize(m *plugin.Manager) (plugin.Plugin, error) {
 	p := &vmPlugin{}
-	m.OnPluginInit(p)
 	return p, nil
 }
 
@@ -86,3 +85,13 @@ func (p *vmPlugin) HandlePluginInit(o plugin.Plugin) {
 		}
 	}
 }
+
+func (p *vmPlugin) HandleShutdown() {
+	if p.vm == nil {
+		logrus.Warnln("vm: shutting down uninitialized plugin")
+		return
+	}
+	if err := p.vm.Shutdown(); err != nil {
+		logrus.Warnln("error shutting down vm:", err)
+	}
+}

vm/scheduler.go

@@ -171,7 +171,7 @@ func (s *scheduler) stop() error {
 	select {
 	case <-time.After(500 * time.Millisecond):
 		// soft timeout, try emptying the jobs queue and interrupting execution
-		logrus.Warnln("vm soft time out expired, flushing remaining jobs without done them")
+		logrus.Warnln("vm soft time out expired, flushing remaining jobs without processing them")
 		s.drain()
 		s.runtime.inner.Interrupt("vm is shutting down")
 		// requeue the stop job since we just flushed it down the drain