18 files changed, 353 insertions, 166 deletions

diff --git a/modules/cron/cron.go b/modules/cron/cron.go
index 795fafb51f..f4511a8e79 100644
--- a/modules/cron/cron.go
+++ b/modules/cron/cron.go
@@ -6,9 +6,11 @@
 package cron
 
 import (
+	"context"
 	"time"
 
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/migrations"
 	"code.gitea.io/gitea/modules/setting"
@@ -37,17 +39,19 @@ var taskStatusTable = sync.NewStatusTable()
 type Func func()
 
 // WithUnique wrap a cron func with an unique running check
-func WithUnique(name string, body Func) Func {
+func WithUnique(name string, body func(context.Context)) Func {
 	return func() {
 		if !taskStatusTable.StartIfNotRunning(name) {
 			return
 		}
 		defer taskStatusTable.Stop(name)
-		body()
+		graceful.GetManager().RunWithShutdownContext(body)
 	}
 }
 
 // NewContext begins cron tasks
+// Each cron task is run within the shutdown context as a running server
+// AtShutdown the cron server is stopped
 func NewContext() {
 	var (
 		entry *cron.Entry
@@ -129,6 +133,7 @@ func NewContext() {
 	go WithUnique(updateMigrationPosterID, migrations.UpdateMigrationPosterID)()
 
 	c.Start()
+	graceful.GetManager().RunAtShutdown(context.Background(), c.Stop)
 }
 
 // ListTasks returns all running cron tasks.
diff --git a/modules/git/git.go b/modules/git/git.go
index 286e1ad8b4..d5caaa0912 100644
--- a/modules/git/git.go
+++ b/modules/git/git.go
@@ -106,7 +106,8 @@ func SetExecutablePath(path string) error {
 }
 
 // Init initializes git module
-func Init() error {
+func Init(ctx context.Context) error {
+	DefaultContext = ctx
 	// Git requires setting user.name and user.email in order to commit changes.
 	for configKey, defaultValue := range map[string]string{"user.name": "Gitea", "user.email": "gitea@fake.local"} {
 		if stdout, stderr, err := process.GetManager().Exec("git.Init(get setting)", GitExecutable, "config", "--get", configKey); err != nil || strings.TrimSpace(stdout) == "" {
diff --git a/modules/git/git_test.go b/modules/git/git_test.go
index 0c6259a9c5..27951d639b 100644
--- a/modules/git/git_test.go
+++ b/modules/git/git_test.go
@@ -5,6 +5,7 @@
 package git
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"testing"
@@ -16,7 +17,7 @@ func fatalTestError(fmtStr string, args ...interface{}) {
 }
 
 func TestMain(m *testing.M) {
-	if err := Init(); err != nil {
+	if err := Init(context.Background()); err != nil {
 		fatalTestError("Init failed: %v", err)
 	}
 
diff --git a/modules/graceful/context.go b/modules/graceful/context.go
index a4a4df7dea..1ad1109b4e 100644
--- a/modules/graceful/context.go
+++ b/modules/graceful/context.go
@@ -62,7 +62,7 @@ func (ctx *ChannelContext) Value(key interface{}) interface{} {
 // ShutdownContext returns a context.Context that is Done at shutdown
 // Callers using this context should ensure that they are registered as a running server
 // in order that they are waited for.
-func (g *gracefulManager) ShutdownContext() context.Context {
+func (g *Manager) ShutdownContext() context.Context {
 	return &ChannelContext{
 		done: g.IsShutdown(),
 		err:  ErrShutdown,
@@ -72,7 +72,7 @@ func (g *gracefulManager) ShutdownContext() context.Context {
 // HammerContext returns a context.Context that is Done at hammer
 // Callers using this context should ensure that they are registered as a running server
 // in order that they are waited for.
-func (g *gracefulManager) HammerContext() context.Context {
+func (g *Manager) HammerContext() context.Context {
 	return &ChannelContext{
 		done: g.IsHammer(),
 		err:  ErrHammer,
@@ -82,7 +82,7 @@ func (g *gracefulManager) HammerContext() context.Context {
 // TerminateContext returns a context.Context that is Done at terminate
 // Callers using this context should ensure that they are registered as a terminating server
 // in order that they are waited for.
-func (g *gracefulManager) TerminateContext() context.Context {
+func (g *Manager) TerminateContext() context.Context {
 	return &ChannelContext{
 		done: g.IsTerminate(),
 		err:  ErrTerminate,
diff --git a/modules/graceful/manager.go b/modules/graceful/manager.go
index b9a56ca9c6..eec675e297 100644
--- a/modules/graceful/manager.go
+++ b/modules/graceful/manager.go
@@ -6,9 +6,9 @@ package graceful
 
 import (
 	"context"
+	"sync"
 	"time"
 
-	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/process"
 	"code.gitea.io/gitea/modules/setting"
@@ -34,14 +34,24 @@ const (
 const numberOfServersToCreate = 3
 
 // Manager represents the graceful server manager interface
-var Manager *gracefulManager
-
-func init() {
-	Manager = newGracefulManager(context.Background())
-	// Set the git default context to the HammerContext
-	git.DefaultContext = Manager.HammerContext()
-	// Set the process default context to the HammerContext
-	process.DefaultContext = Manager.HammerContext()
+var manager *Manager
+
+var initOnce = sync.Once{}
+
+// GetManager returns the Manager
+func GetManager() *Manager {
+	InitManager(context.Background())
+	return manager
+}
+
+// InitManager creates the graceful manager in the provided context
+func InitManager(ctx context.Context) {
+	initOnce.Do(func() {
+		manager = newGracefulManager(ctx)
+
+		// Set the process default context to the HammerContext
+		process.DefaultContext = manager.HammerContext()
+	})
 }
 
 // CallbackWithContext is combined runnable and context to watch to see if the caller has finished
@@ -61,7 +71,7 @@ type RunnableWithShutdownFns func(atShutdown, atTerminate func(context.Context,
 // Please note that use of the atShutdown and atTerminate callbacks will create go-routines that will wait till their respective signals
 // - users must therefore be careful to only call these as necessary.
 // If run is not expected to run indefinitely RunWithShutdownChan is likely to be more appropriate.
-func (g *gracefulManager) RunWithShutdownFns(run RunnableWithShutdownFns) {
+func (g *Manager) RunWithShutdownFns(run RunnableWithShutdownFns) {
 	g.runningServerWaitGroup.Add(1)
 	defer g.runningServerWaitGroup.Done()
 	run(func(ctx context.Context, atShutdown func()) {
@@ -90,7 +100,7 @@ type RunnableWithShutdownChan func(atShutdown <-chan struct{}, atTerminate Callb
 // (Optionally IsHammer may be waited for instead however, this should be avoided if possible.)
 // The callback function provided to atTerminate must return once termination is complete.
 // Please note that use of the atTerminate function will create a go-routine that will wait till terminate - users must therefore be careful to only call this as necessary.
-func (g *gracefulManager) RunWithShutdownChan(run RunnableWithShutdownChan) {
+func (g *Manager) RunWithShutdownChan(run RunnableWithShutdownChan) {
 	g.runningServerWaitGroup.Add(1)
 	defer g.runningServerWaitGroup.Done()
 	run(g.IsShutdown(), func(ctx context.Context, atTerminate func()) {
@@ -101,14 +111,14 @@ func (g *gracefulManager) RunWithShutdownChan(run RunnableWithShutdownChan) {
 // RunWithShutdownContext takes a function that has a context to watch for shutdown.
 // After the provided context is Done(), the main function must return once shutdown is complete.
 // (Optionally the HammerContext may be obtained and waited for however, this should be avoided if possible.)
-func (g *gracefulManager) RunWithShutdownContext(run func(context.Context)) {
+func (g *Manager) RunWithShutdownContext(run func(context.Context)) {
 	g.runningServerWaitGroup.Add(1)
 	defer g.runningServerWaitGroup.Done()
 	run(g.ShutdownContext())
 }
 
 // RunAtTerminate adds to the terminate wait group and creates a go-routine to run the provided function at termination
-func (g *gracefulManager) RunAtTerminate(ctx context.Context, terminate func()) {
+func (g *Manager) RunAtTerminate(ctx context.Context, terminate func()) {
 	g.terminateWaitGroup.Add(1)
 	go func() {
 		select {
@@ -121,7 +131,7 @@ func (g *gracefulManager) RunAtTerminate(ctx context.Context, terminate func())
 }
 
 // RunAtShutdown creates a go-routine to run the provided function at shutdown
-func (g *gracefulManager) RunAtShutdown(ctx context.Context, shutdown func()) {
+func (g *Manager) RunAtShutdown(ctx context.Context, shutdown func()) {
 	go func() {
 		select {
 		case <-g.IsShutdown():
@@ -132,7 +142,7 @@ func (g *gracefulManager) RunAtShutdown(ctx context.Context, shutdown func()) {
 }
 
 // RunAtHammer creates a go-routine to run the provided function at shutdown
-func (g *gracefulManager) RunAtHammer(ctx context.Context, hammer func()) {
+func (g *Manager) RunAtHammer(ctx context.Context, hammer func()) {
 	go func() {
 		select {
 		case <-g.IsHammer():
@@ -141,7 +151,7 @@ func (g *gracefulManager) RunAtHammer(ctx context.Context, hammer func()) {
 		}
 	}()
 }
-func (g *gracefulManager) doShutdown() {
+func (g *Manager) doShutdown() {
 	if !g.setStateTransition(stateRunning, stateShuttingDown) {
 		return
 	}
@@ -158,48 +168,47 @@ func (g *gracefulManager) doShutdown() {
 		g.doHammerTime(0)
 		<-time.After(1 * time.Second)
 		g.doTerminate()
+		g.WaitForTerminate()
+		g.lock.Lock()
+		close(g.done)
+		g.lock.Unlock()
 	}()
 }
 
-func (g *gracefulManager) doHammerTime(d time.Duration) {
+func (g *Manager) doHammerTime(d time.Duration) {
 	time.Sleep(d)
+	g.lock.Lock()
 	select {
 	case <-g.hammer:
 	default:
 		log.Warn("Setting Hammer condition")
 		close(g.hammer)
 	}
-
+	g.lock.Unlock()
 }
 
-func (g *gracefulManager) doTerminate() {
+func (g *Manager) doTerminate() {
 	if !g.setStateTransition(stateShuttingDown, stateTerminate) {
 		return
 	}
 	g.lock.Lock()
-	close(g.terminate)
+	select {
+	case <-g.terminate:
+	default:
+		log.Warn("Terminating")
+		close(g.terminate)
+	}
 	g.lock.Unlock()
 }
 
 // IsChild returns if the current process is a child of previous Gitea process
-func (g *gracefulManager) IsChild() bool {
+func (g *Manager) IsChild() bool {
 	return g.isChild
 }
 
 // IsShutdown returns a channel which will be closed at shutdown.
 // The order of closure is IsShutdown, IsHammer (potentially), IsTerminate
-func (g *gracefulManager) IsShutdown() <-chan struct{} {
-	g.lock.RLock()
-	if g.shutdown == nil {
-		g.lock.RUnlock()
-		g.lock.Lock()
-		if g.shutdown == nil {
-			g.shutdown = make(chan struct{})
-		}
-		defer g.lock.Unlock()
-		return g.shutdown
-	}
-	defer g.lock.RUnlock()
+func (g *Manager) IsShutdown() <-chan struct{} {
 	return g.shutdown
 }
 
@@ -207,65 +216,43 @@ func (g *gracefulManager) IsShutdown() <-chan struct{} {
 // The order of closure is IsShutdown, IsHammer (potentially), IsTerminate
 // Servers running within the running server wait group should respond to IsHammer
 // if not shutdown already
-func (g *gracefulManager) IsHammer() <-chan struct{} {
-	g.lock.RLock()
-	if g.hammer == nil {
-		g.lock.RUnlock()
-		g.lock.Lock()
-		if g.hammer == nil {
-			g.hammer = make(chan struct{})
-		}
-		defer g.lock.Unlock()
-		return g.hammer
-	}
-	defer g.lock.RUnlock()
+func (g *Manager) IsHammer() <-chan struct{} {
 	return g.hammer
 }
 
 // IsTerminate returns a channel which will be closed at terminate
 // The order of closure is IsShutdown, IsHammer (potentially), IsTerminate
 // IsTerminate will only close once all running servers have stopped
-func (g *gracefulManager) IsTerminate() <-chan struct{} {
-	g.lock.RLock()
-	if g.terminate == nil {
-		g.lock.RUnlock()
-		g.lock.Lock()
-		if g.terminate == nil {
-			g.terminate = make(chan struct{})
-		}
-		defer g.lock.Unlock()
-		return g.terminate
-	}
-	defer g.lock.RUnlock()
+func (g *Manager) IsTerminate() <-chan struct{} {
 	return g.terminate
 }
 
 // ServerDone declares a running server done and subtracts one from the
 // running server wait group. Users probably do not want to call this
 // and should use one of the RunWithShutdown* functions
-func (g *gracefulManager) ServerDone() {
+func (g *Manager) ServerDone() {
 	g.runningServerWaitGroup.Done()
 }
 
 // WaitForServers waits for all running servers to finish. Users should probably
 // instead use AtTerminate or IsTerminate
-func (g *gracefulManager) WaitForServers() {
+func (g *Manager) WaitForServers() {
 	g.runningServerWaitGroup.Wait()
 }
 
 // WaitForTerminate waits for all terminating actions to finish.
 // Only the main go-routine should use this
-func (g *gracefulManager) WaitForTerminate() {
+func (g *Manager) WaitForTerminate() {
 	g.terminateWaitGroup.Wait()
 }
 
-func (g *gracefulManager) getState() state {
+func (g *Manager) getState() state {
 	g.lock.RLock()
 	defer g.lock.RUnlock()
 	return g.state
 }
 
-func (g *gracefulManager) setStateTransition(old, new state) bool {
+func (g *Manager) setStateTransition(old, new state) bool {
 	if old != g.getState() {
 		return false
 	}
@@ -279,7 +266,7 @@ func (g *gracefulManager) setStateTransition(old, new state) bool {
 	return true
 }
 
-func (g *gracefulManager) setState(st state) {
+func (g *Manager) setState(st state) {
 	g.lock.Lock()
 	defer g.lock.Unlock()
 
@@ -288,6 +275,31 @@ func (g *gracefulManager) setState(st state) {
 
 // InformCleanup tells the cleanup wait group that we have either taken a listener
 // or will not be taking a listener
-func (g *gracefulManager) InformCleanup() {
+func (g *Manager) InformCleanup() {
 	g.createServerWaitGroup.Done()
 }
+
+// Done allows the manager to be viewed as a context.Context, it returns a channel that is closed when the server is finished terminating
+func (g *Manager) Done() <-chan struct{} {
+	return g.done
+}
+
+// Err allows the manager to be viewed as a context.Context done at Terminate, it returns ErrTerminate
+func (g *Manager) Err() error {
+	select {
+	case <-g.Done():
+		return ErrTerminate
+	default:
+		return nil
+	}
+}
+
+// Value allows the manager to be viewed as a context.Context done at Terminate, it has no values
+func (g *Manager) Value(key interface{}) interface{} {
+	return nil
+}
+
+// Deadline returns nil as there is no fixed Deadline for the manager, it allows the manager to be viewed as a context.Context
+func (g *Manager) Deadline() (deadline time.Time, ok bool) {
+	return
+}
diff --git a/modules/graceful/manager_unix.go b/modules/graceful/manager_unix.go
index 1ffc59f0df..323c6a4111 100644
--- a/modules/graceful/manager_unix.go
+++ b/modules/graceful/manager_unix.go
@@ -19,7 +19,8 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 )
 
-type gracefulManager struct {
+// Manager manages the graceful shutdown process
+type Manager struct {
 	isChild                bool
 	forked                 bool
 	lock                   *sync.RWMutex
@@ -27,27 +28,37 @@ type gracefulManager struct {
 	shutdown               chan struct{}
 	hammer                 chan struct{}
 	terminate              chan struct{}
+	done                   chan struct{}
 	runningServerWaitGroup sync.WaitGroup
 	createServerWaitGroup  sync.WaitGroup
 	terminateWaitGroup     sync.WaitGroup
 }
 
-func newGracefulManager(ctx context.Context) *gracefulManager {
-	manager := &gracefulManager{
+func newGracefulManager(ctx context.Context) *Manager {
+	manager := &Manager{
 		isChild: len(os.Getenv(listenFDs)) > 0 && os.Getppid() > 1,
 		lock:    &sync.RWMutex{},
 	}
 	manager.createServerWaitGroup.Add(numberOfServersToCreate)
-	manager.Run(ctx)
+	manager.start(ctx)
 	return manager
 }
 
-func (g *gracefulManager) Run(ctx context.Context) {
+func (g *Manager) start(ctx context.Context) {
+	// Make channels
+	g.terminate = make(chan struct{})
+	g.shutdown = make(chan struct{})
+	g.hammer = make(chan struct{})
+	g.done = make(chan struct{})
+
+	// Set the running state & handle signals
 	g.setState(stateRunning)
 	go g.handleSignals(ctx)
-	c := make(chan struct{})
+
+	// Handle clean up of unused provided listeners	and delayed start-up
+	startupDone := make(chan struct{})
 	go func() {
-		defer close(c)
+		defer close(startupDone)
 		// Wait till we're done getting all of the listeners and then close
 		// the unused ones
 		g.createServerWaitGroup.Wait()
@@ -58,9 +69,19 @@ func (g *gracefulManager) Run(ctx context.Context) {
 	if setting.StartupTimeout > 0 {
 		go func() {
 			select {
-			case <-c:
+			case <-startupDone:
 				return
 			case <-g.IsShutdown():
+				func() {
+					// When waitgroup counter goes negative it will panic - we don't care about this so we can just ignore it.
+					defer func() {
+						_ = recover()
+					}()
+					// Ensure that the createServerWaitGroup stops waiting
+					for {
+						g.createServerWaitGroup.Done()
+					}
+				}()
 				return
 			case <-time.After(setting.StartupTimeout):
 				log.Error("Startup took too long! Shutting down")
@@ -70,7 +91,7 @@ func (g *gracefulManager) Run(ctx context.Context) {
 	}
 }
 
-func (g *gracefulManager) handleSignals(ctx context.Context) {
+func (g *Manager) handleSignals(ctx context.Context) {
 	signalChannel := make(chan os.Signal, 1)
 
 	signal.Notify(
@@ -123,7 +144,7 @@ func (g *gracefulManager) handleSignals(ctx context.Context) {
 	}
 }
 
-func (g *gracefulManager) doFork() error {
+func (g *Manager) doFork() error {
 	g.lock.Lock()
 	if g.forked {
 		g.lock.Unlock()
@@ -139,7 +160,9 @@ func (g *gracefulManager) doFork() error {
 	return err
 }
 
-func (g *gracefulManager) RegisterServer() {
+// RegisterServer registers the running of a listening server, in the case of unix this means that the parent process can now die.
+// Any call to RegisterServer must be matched by a call to ServerDone
+func (g *Manager) RegisterServer() {
 	KillParent()
 	g.runningServerWaitGroup.Add(1)
 }
diff --git a/modules/graceful/manager_windows.go b/modules/graceful/manager_windows.go
index 26c791e6ed..526fc0bd24 100644
--- a/modules/graceful/manager_windows.go
+++ b/modules/graceful/manager_windows.go
@@ -30,7 +30,8 @@ const (
 	acceptHammerCode = svc.Accepted(hammerCode)
 )
 
-type gracefulManager struct {
+// Manager manages the graceful shutdown process
+type Manager struct {
 	ctx                    context.Context
 	isChild                bool
 	lock                   *sync.RWMutex
@@ -38,27 +39,37 @@ type gracefulManager struct {
 	shutdown               chan struct{}
 	hammer                 chan struct{}
 	terminate              chan struct{}
+	done                   chan struct{}
 	runningServerWaitGroup sync.WaitGroup
 	createServerWaitGroup  sync.WaitGroup
 	terminateWaitGroup     sync.WaitGroup
 }
 
-func newGracefulManager(ctx context.Context) *gracefulManager {
-	manager := &gracefulManager{
+func newGracefulManager(ctx context.Context) *Manager {
+	manager := &Manager{
 		isChild: false,
 		lock:    &sync.RWMutex{},
 		ctx:     ctx,
 	}
 	manager.createServerWaitGroup.Add(numberOfServersToCreate)
-	manager.Run()
+	manager.start()
 	return manager
 }
 
-func (g *gracefulManager) Run() {
+func (g *Manager) start() {
+	// Make channels
+	g.terminate = make(chan struct{})
+	g.shutdown = make(chan struct{})
+	g.hammer = make(chan struct{})
+	g.done = make(chan struct{})
+
+	// Set the running state
 	g.setState(stateRunning)
 	if skip, _ := strconv.ParseBool(os.Getenv("SKIP_MINWINSVC")); skip {
 		return
 	}
+
+	// Make SVC process
 	run := svc.Run
 	isInteractive, err := svc.IsAnInteractiveSession()
 	if err != nil {
@@ -71,8 +82,8 @@ func (g *gracefulManager) Run() {
 	go run(WindowsServiceName, g)
 }
 
-// Execute makes gracefulManager implement svc.Handler
-func (g *gracefulManager) Execute(args []string, changes <-chan svc.ChangeRequest, status chan<- svc.Status) (svcSpecificEC bool, exitCode uint32) {
+// Execute makes Manager implement svc.Handler
+func (g *Manager) Execute(args []string, changes <-chan svc.ChangeRequest, status chan<- svc.Status) (svcSpecificEC bool, exitCode uint32) {
 	if setting.StartupTimeout > 0 {
 		status <- svc.Status{State: svc.StartPending}
 	} else {
@@ -141,11 +152,13 @@ hammerLoop:
 	return false, 0
 }
 
-func (g *gracefulManager) RegisterServer() {
+// RegisterServer registers the running of a listening server.
+// Any call to RegisterServer must be matched by a call to ServerDone
+func (g *Manager) RegisterServer() {
 	g.runningServerWaitGroup.Add(1)
 }
 
-func (g *gracefulManager) awaitServer(limit time.Duration) bool {
+func (g *Manager) awaitServer(limit time.Duration) bool {
 	c := make(chan struct{})
 	go func() {
 		defer close(c)
diff --git a/modules/graceful/net_unix.go b/modules/graceful/net_unix.go
index 5550c09f42..1e496e9d91 100644
--- a/modules/graceful/net_unix.go
+++ b/modules/graceful/net_unix.go
@@ -101,7 +101,7 @@ func CloseProvidedListeners() error {
 // creates a new one using net.Listen.
 func GetListener(network, address string) (net.Listener, error) {
 	// Add a deferral to say that we've tried to grab a listener
-	defer Manager.InformCleanup()
+	defer GetManager().InformCleanup()
 	switch network {
 	case "tcp", "tcp4", "tcp6":
 		tcpAddr, err := net.ResolveTCPAddr(network, address)
diff --git a/modules/graceful/restart_unix.go b/modules/graceful/restart_unix.go
index 3fc4f0511d..9a94e5fa67 100644
--- a/modules/graceful/restart_unix.go
+++ b/modules/graceful/restart_unix.go
@@ -22,7 +22,7 @@ var killParent sync.Once
 // KillParent sends the kill signal to the parent process if we are a child
 func KillParent() {
 	killParent.Do(func() {
-		if Manager.IsChild() {
+		if GetManager().IsChild() {
 			ppid := syscall.Getppid()
 			if ppid > 1 {
 				_ = syscall.Kill(ppid, syscall.SIGTERM)
diff --git a/modules/graceful/server.go b/modules/graceful/server.go
index c6692cbb75..30fb8cdffa 100644
--- a/modules/graceful/server.go
+++ b/modules/graceful/server.go
@@ -47,7 +47,7 @@ type Server struct {
 
 // NewServer creates a server on network at provided address
 func NewServer(network, address string) *Server {
-	if Manager.IsChild() {
+	if GetManager().IsChild() {
 		log.Info("Restarting new server: %s:%s on PID: %d", network, address, os.Getpid())
 	} else {
 		log.Info("Starting new server: %s:%s on PID: %d", network, address, os.Getpid())
@@ -138,12 +138,12 @@ func (srv *Server) ListenAndServeTLSConfig(tlsConfig *tls.Config, serve ServeFun
 func (srv *Server) Serve(serve ServeFunction) error {
 	defer log.Debug("Serve() returning... (PID: %d)", syscall.Getpid())
 	srv.setState(stateRunning)
-	Manager.RegisterServer()
+	GetManager().RegisterServer()
 	err := serve(srv.listener)
 	log.Debug("Waiting for connections to finish... (PID: %d)", syscall.Getpid())
 	srv.wg.Wait()
 	srv.setState(stateTerminate)
-	Manager.ServerDone()
+	GetManager().ServerDone()
 	// use of closed means that the listeners are closed - i.e. we should be shutting down - return nil
 	if err != nil && strings.Contains(err.Error(), "use of closed") {
 		return nil
diff --git a/modules/graceful/server_hooks.go b/modules/graceful/server_hooks.go
index 74b0fcb885..c634905711 100644
--- a/modules/graceful/server_hooks.go
+++ b/modules/graceful/server_hooks.go
@@ -14,15 +14,15 @@ import (
 // awaitShutdown waits for the shutdown signal from the Manager
 func (srv *Server) awaitShutdown() {
 	select {
-	case <-Manager.IsShutdown():
+	case <-GetManager().IsShutdown():
 		// Shutdown
 		srv.doShutdown()
-	case <-Manager.IsHammer():
+	case <-GetManager().IsHammer():
 		// Hammer
 		srv.doShutdown()
 		srv.doHammer()
 	}
-	<-Manager.IsHammer()
+	<-GetManager().IsHammer()
 	srv.doHammer()
 }
 
diff --git a/modules/indexer/code/bleve.go b/modules/indexer/code/bleve.go
index c8e1bb1879..bb2fc5bc74 100644
--- a/modules/indexer/code/bleve.go
+++ b/modules/indexer/code/bleve.go
@@ -6,6 +6,7 @@ package code
 
 import (
 	"fmt"
+	"os"
 	"strconv"
 	"strings"
 	"time"
@@ -34,10 +35,11 @@ func InitRepoIndexer() {
 		return
 	}
 	waitChannel := make(chan time.Duration)
+	// FIXME: graceful: This should use a persistable queue
 	repoIndexerOperationQueue = make(chan repoIndexerOperation, setting.Indexer.UpdateQueueLength)
 	go func() {
 		start := time.Now()
-		log.Info("Initializing Repository Indexer")
+		log.Info("PID: %d: Initializing Repository Indexer", os.Getpid())
 		initRepoIndexer(populateRepoIndexerAsynchronously)
 		go processRepoIndexerOperationQueue()
 		waitChannel <- time.Since(start)
@@ -45,7 +47,7 @@ func InitRepoIndexer() {
 	if setting.Indexer.StartupTimeout > 0 {
 		go func() {
 			timeout := setting.Indexer.StartupTimeout
-			if graceful.Manager.IsChild() && setting.GracefulHammerTime > 0 {
+			if graceful.GetManager().IsChild() && setting.GracefulHammerTime > 0 {
 				timeout += setting.GracefulHammerTime
 			}
 			select {
@@ -70,13 +72,6 @@ func populateRepoIndexerAsynchronously() error {
 		return nil
 	}
 
-	// if there is any existing repo indexer metadata in the DB, delete it
-	// since we are starting afresh. Also, xorm requires deletes to have a
-	// condition, and we want to delete everything, thus 1=1.
-	if err := models.DeleteAllRecords("repo_indexer_status"); err != nil {
-		return err
-	}
-
 	var maxRepoID int64
 	if maxRepoID, err = models.GetMaxID("repository"); err != nil {
 		return err
@@ -87,44 +82,59 @@ func populateRepoIndexerAsynchronously() error {
 
 // populateRepoIndexer populate the repo indexer with pre-existing data. This
 // should only be run when the indexer is created for the first time.
+// FIXME: graceful: This should use a persistable queue
 func populateRepoIndexer(maxRepoID int64) {
 	log.Info("Populating the repo indexer with existing repositories")
+
+	isShutdown := graceful.GetManager().IsShutdown()
+
 	// start with the maximum existing repo ID and work backwards, so that we
 	// don't include repos that are created after gitea starts; such repos will
 	// already be added to the indexer, and we don't need to add them again.
 	for maxRepoID > 0 {
-		repos := make([]*models.Repository, 0, models.RepositoryListDefaultPageSize)
-		err := models.FindByMaxID(maxRepoID, models.RepositoryListDefaultPageSize, &repos)
+		select {
+		case <-isShutdown:
+			log.Info("Repository Indexer population shutdown before completion")
+			return
+		default:
+		}
+		ids, err := models.GetUnindexedRepos(maxRepoID, 0, 50)
 		if err != nil {
 			log.Error("populateRepoIndexer: %v", err)
 			return
-		} else if len(repos) == 0 {
+		} else if len(ids) == 0 {
 			break
 		}
-		for _, repo := range repos {
+		for _, id := range ids {
+			select {
+			case <-isShutdown:
+				log.Info("Repository Indexer population shutdown before completion")
+				return
+			default:
+			}
 			repoIndexerOperationQueue <- repoIndexerOperation{
-				repoID:  repo.ID,
+				repoID:  id,
 				deleted: false,
 			}
-			maxRepoID = repo.ID - 1
+			maxRepoID = id - 1
 		}
 	}
-	log.Info("Done populating the repo indexer with existing repositories")
+	log.Info("Done (re)populating the repo indexer with existing repositories")
 }
 
 func updateRepoIndexer(repoID int64) error {
 	repo, err := models.GetRepositoryByID(repoID)
 	if err != nil {
-		return err
+		return fmt.Errorf("UpdateRepoIndexer: Unable to GetRepositoryByID: %d, Error: %v", repoID, err)
 	}
 
 	sha, err := getDefaultBranchSha(repo)
 	if err != nil {
-		return err
+		return fmt.Errorf("UpdateRepoIndexer: Unable to GetDefaultBranchSha for: %s/%s, Error: %v", repo.MustOwnerName(), repo.Name, err)
 	}
 	changes, err := getRepoChanges(repo, sha)
 	if err != nil {
-		return err
+		return fmt.Errorf("UpdateRepoIndexer: Unable to GetRepoChanges for: %s/%s Sha: %s Error: %v", repo.MustOwnerName(), repo.Name, sha, err)
 	} else if changes == nil {
 		return nil
 	}
@@ -132,16 +142,16 @@ func updateRepoIndexer(repoID int64) error {
 	batch := RepoIndexerBatch()
 	for _, update := range changes.Updates {
 		if err := addUpdate(update, repo, batch); err != nil {
-			return err
+			return fmt.Errorf("UpdateRepoIndexer: Unable to addUpdate to: %s/%s Sha: %s, update: %s(%s) Error: %v", repo.MustOwnerName(), repo.Name, sha, update.Filename, update.BlobSha, err)
 		}
 	}
 	for _, filename := range changes.RemovedFilenames {
 		if err := addDelete(filename, repo, batch); err != nil {
-			return err
+			return fmt.Errorf("UpdateRepoIndexer: Unable to addDelete to: %s/%s Sha: %s, filename: %s Error: %v", repo.MustOwnerName(), repo.Name, sha, filename, err)
 		}
 	}
 	if err = batch.Flush(); err != nil {
-		return err
+		return fmt.Errorf("UpdateRepoIndexer: Unable to flush batch to indexer for repo: %s/%s Error: %v", repo.MustOwnerName(), repo.Name, err)
 	}
 	return repo.UpdateIndexerStatus(sha)
 }
@@ -322,20 +332,26 @@ func nonGenesisChanges(repo *models.Repository, revision string) (*repoChanges,
 
 func processRepoIndexerOperationQueue() {
 	for {
-		op := <-repoIndexerOperationQueue
-		var err error
-		if op.deleted {
-			if err = deleteRepoFromIndexer(op.repoID); err != nil {
-				log.Error("deleteRepoFromIndexer: %v", err)
+		select {
+		case op := <-repoIndexerOperationQueue:
+			var err error
+			if op.deleted {
+				if err = deleteRepoFromIndexer(op.repoID); err != nil {
+					log.Error("DeleteRepoFromIndexer: %v", err)
+				}
+			} else {
+				if err = updateRepoIndexer(op.repoID); err != nil {
+					log.Error("updateRepoIndexer: %v", err)
+				}
 			}
-		} else {
-			if err = updateRepoIndexer(op.repoID); err != nil {
-				log.Error("updateRepoIndexer: %v", err)
+			for _, watcher := range op.watchers {
+				watcher <- err
 			}
+		case <-graceful.GetManager().IsShutdown():
+			log.Info("PID: %d Repository indexer queue processing stopped", os.Getpid())
+			return
 		}
-		for _, watcher := range op.watchers {
-			watcher <- err
-		}
+
 	}
 }
 
diff --git a/modules/indexer/code/repo.go b/modules/indexer/code/repo.go
index 31f0fa7f3d..bc5f317b7d 100644
--- a/modules/indexer/code/repo.go
+++ b/modules/indexer/code/repo.go
@@ -5,9 +5,13 @@
 package code
 
 import (
+	"context"
+	"os"
 	"strings"
 	"sync"
 
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 
@@ -104,21 +108,50 @@ func (update RepoIndexerUpdate) AddToFlushingBatch(batch rupture.FlushingBatch)
 func initRepoIndexer(populateIndexer func() error) {
 	indexer, err := openIndexer(setting.Indexer.RepoPath, repoIndexerLatestVersion)
 	if err != nil {
-		log.Fatal("InitRepoIndexer: %v", err)
+		log.Fatal("InitRepoIndexer %s: %v", setting.Indexer.RepoPath, err)
 	}
 	if indexer != nil {
 		indexerHolder.set(indexer)
+		closeAtTerminate()
+
+		// Continue population from where left off
+		if err = populateIndexer(); err != nil {
+			log.Fatal("PopulateRepoIndex: %v", err)
+		}
 		return
 	}
 
 	if err = createRepoIndexer(setting.Indexer.RepoPath, repoIndexerLatestVersion); err != nil {
 		log.Fatal("CreateRepoIndexer: %v", err)
 	}
+	closeAtTerminate()
+
+	// if there is any existing repo indexer metadata in the DB, delete it
+	// since we are starting afresh. Also, xorm requires deletes to have a
+	// condition, and we want to delete everything, thus 1=1.
+	if err := models.DeleteAllRecords("repo_indexer_status"); err != nil {
+		log.Fatal("DeleteAllRepoIndexerStatus: %v", err)
+	}
+
 	if err = populateIndexer(); err != nil {
 		log.Fatal("PopulateRepoIndex: %v", err)
 	}
 }
 
+func closeAtTerminate() {
+	graceful.GetManager().RunAtTerminate(context.Background(), func() {
+		log.Debug("Closing repo indexer")
+		indexer := indexerHolder.get()
+		if indexer != nil {
+			err := indexer.Close()
+			if err != nil {
+				log.Error("Error whilst closing the repository indexer: %v", err)
+			}
+		}
+		log.Info("PID: %d Repository Indexer closed", os.Getpid())
+	})
+}
+
 // createRepoIndexer create a repo indexer if one does not already exist
 func createRepoIndexer(path string, latestVersion int) error {
 	docMapping := bleve.NewDocumentMapping()
diff --git a/modules/indexer/issues/indexer.go b/modules/indexer/issues/indexer.go
index 78eba58095..50b8d6d224 100644
--- a/modules/indexer/issues/indexer.go
+++ b/modules/indexer/issues/indexer.go
@@ -172,7 +172,7 @@ func InitIssueIndexer(syncReindex bool) {
 	} else if setting.Indexer.StartupTimeout > 0 {
 		go func() {
 			timeout := setting.Indexer.StartupTimeout
-			if graceful.Manager.IsChild() && setting.GracefulHammerTime > 0 {
+			if graceful.GetManager().IsChild() && setting.GracefulHammerTime > 0 {
 				timeout += setting.GracefulHammerTime
 			}
 			select {
diff --git a/modules/migrations/update.go b/modules/migrations/update.go
index d1465b2baf..3d0962657c 100644
--- a/modules/migrations/update.go
+++ b/modules/migrations/update.go
@@ -5,21 +5,28 @@
 package migrations
 
 import (
+	"context"
+
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/structs"
 )
 
 // UpdateMigrationPosterID updates all migrated repositories' issues and comments posterID
-func UpdateMigrationPosterID() {
+func UpdateMigrationPosterID(ctx context.Context) {
 	for _, gitService := range structs.SupportedFullGitService {
-		if err := updateMigrationPosterIDByGitService(gitService); err != nil {
+		select {
+		case <-ctx.Done():
+			log.Warn("UpdateMigrationPosterID aborted due to shutdown before %s", gitService.Name())
+		default:
+		}
+		if err := updateMigrationPosterIDByGitService(ctx, gitService); err != nil {
 			log.Error("updateMigrationPosterIDByGitService failed: %v", err)
 		}
 	}
 }
 
-func updateMigrationPosterIDByGitService(tp structs.GitServiceType) error {
+func updateMigrationPosterIDByGitService(ctx context.Context, tp structs.GitServiceType) error {
 	provider := tp.Name()
 	if len(provider) == 0 {
 		return nil
@@ -28,6 +35,13 @@ func updateMigrationPosterIDByGitService(tp structs.GitServiceType) error {
 	const batchSize = 100
 	var start int
 	for {
+		select {
+		case <-ctx.Done():
+			log.Warn("UpdateMigrationPosterIDByGitService(%s) aborted due to shutdown", tp.Name())
+			return nil
+		default:
+		}
+
 		users, err := models.FindExternalUsersByProvider(models.FindExternalUserOptions{
 			Provider: provider,
 			Start:    start,
@@ -38,6 +52,12 @@ func updateMigrationPosterIDByGitService(tp structs.GitServiceType) error {
 		}
 
 		for _, user := range users {
+			select {
+			case <-ctx.Done():
+				log.Warn("UpdateMigrationPosterIDByGitService(%s) aborted due to shutdown", tp.Name())
+				return nil
+			default:
+			}
 			externalUserID := user.ExternalID
 			if err := models.UpdateMigrationsByType(tp, externalUserID, user.UserID); err != nil {
 				log.Error("UpdateMigrationsByType type %s external user id %v to local user id %v failed: %v", tp.Name(), user.ExternalID, user.UserID, err)
diff --git a/modules/ssh/ssh_graceful.go b/modules/ssh/ssh_graceful.go
index 4d7557e2ee..f8370ab4db 100644
--- a/modules/ssh/ssh_graceful.go
+++ b/modules/ssh/ssh_graceful.go
@@ -24,5 +24,5 @@ func listen(server *ssh.Server) {
 
 // Unused informs our cleanup routine that we will not be using a ssh port
 func Unused() {
-	graceful.Manager.InformCleanup()
+	graceful.GetManager().InformCleanup()
 }
diff --git a/modules/sync/unique_queue.go b/modules/sync/unique_queue.go
index de694d8560..14644c7d4e 100644
--- a/modules/sync/unique_queue.go
+++ b/modules/sync/unique_queue.go
@@ -1,4 +1,5 @@
 // Copyright 2016 The Gogs Authors. All rights reserved.
+// Copyright 2019 The Gitea Authors. All rights reserved.
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file.
 
@@ -15,8 +16,9 @@ import (
 // This queue is particularly useful for preventing duplicated task
 // of same purpose.
 type UniqueQueue struct {
-	table *StatusTable
-	queue chan string
+	table  *StatusTable
+	queue  chan string
+	closed chan struct{}
 }
 
 // NewUniqueQueue initializes and returns a new UniqueQueue object.
@@ -26,11 +28,43 @@ func NewUniqueQueue(queueLength int) *UniqueQueue {
 	}
 
 	return &UniqueQueue{
-		table: NewStatusTable(),
-		queue: make(chan string, queueLength),
+		table:  NewStatusTable(),
+		queue:  make(chan string, queueLength),
+		closed: make(chan struct{}),
 	}
 }
 
+// Close closes this queue
+func (q *UniqueQueue) Close() {
+	select {
+	case <-q.closed:
+	default:
+		q.table.lock.Lock()
+		select {
+		case <-q.closed:
+		default:
+			close(q.closed)
+		}
+		q.table.lock.Unlock()
+	}
+}
+
+// IsClosed returns a channel that is closed when this Queue is closed
+func (q *UniqueQueue) IsClosed() <-chan struct{} {
+	return q.closed
+}
+
+// IDs returns the current ids in the pool
+func (q *UniqueQueue) IDs() []interface{} {
+	q.table.lock.Lock()
+	defer q.table.lock.Unlock()
+	ids := make([]interface{}, 0, len(q.table.pool))
+	for id := range q.table.pool {
+		ids = append(ids, id)
+	}
+	return ids
+}
+
 // Queue returns channel of queue for retrieving instances.
 func (q *UniqueQueue) Queue() <-chan string {
 	return q.queue
@@ -45,18 +79,22 @@ func (q *UniqueQueue) Exist(id interface{}) bool {
 // AddFunc adds new instance to the queue with a custom runnable function,
 // the queue is blocked until the function exits.
 func (q *UniqueQueue) AddFunc(id interface{}, fn func()) {
-	if q.Exist(id) {
-		return
-	}
-
 	idStr := com.ToStr(id)
 	q.table.lock.Lock()
+	if _, ok := q.table.pool[idStr]; ok {
+		return
+	}
 	q.table.pool[idStr] = struct{}{}
 	if fn != nil {
 		fn()
 	}
 	q.table.lock.Unlock()
-	q.queue <- idStr
+	select {
+	case <-q.closed:
+		return
+	case q.queue <- idStr:
+		return
+	}
 }
 
 // Add adds new instance to the queue.
diff --git a/modules/webhook/deliver.go b/modules/webhook/deliver.go
index b262505cea..9f5c938f83 100644
--- a/modules/webhook/deliver.go
+++ b/modules/webhook/deliver.go
@@ -5,6 +5,7 @@
 package webhook
 
 import (
+	"context"
 	"crypto/tls"
 	"fmt"
 	"io/ioutil"
@@ -16,6 +17,7 @@ import (
 	"time"
 
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"github.com/gobwas/glob"
@@ -145,8 +147,14 @@ func Deliver(t *models.HookTask) error {
 }
 
 // DeliverHooks checks and delivers undelivered hooks.
-// TODO: shoot more hooks at same time.
-func DeliverHooks() {
+// FIXME: graceful: This would likely benefit from either a worker pool with dummy queue
+// or a full queue. Then more hooks could be sent at same time.
+func DeliverHooks(ctx context.Context) {
+	select {
+	case <-ctx.Done():
+		return
+	default:
+	}
 	tasks, err := models.FindUndeliveredHookTasks()
 	if err != nil {
 		log.Error("DeliverHooks: %v", err)
@@ -155,33 +163,50 @@ func DeliverHooks() {
 
 	// Update hook task status.
 	for _, t := range tasks {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
 		if err = Deliver(t); err != nil {
 			log.Error("deliver: %v", err)
 		}
 	}
 
 	// Start listening on new hook requests.
-	for repoIDStr := range hookQueue.Queue() {
-		log.Trace("DeliverHooks [repo_id: %v]", repoIDStr)
-		hookQueue.Remove(repoIDStr)
+	for {
+		select {
+		case <-ctx.Done():
+			hookQueue.Close()
+			return
+		case repoIDStr := <-hookQueue.Queue():
+			log.Trace("DeliverHooks [repo_id: %v]", repoIDStr)
+			hookQueue.Remove(repoIDStr)
 
-		repoID, err := com.StrTo(repoIDStr).Int64()
-		if err != nil {
-			log.Error("Invalid repo ID: %s", repoIDStr)
-			continue
-		}
+			repoID, err := com.StrTo(repoIDStr).Int64()
+			if err != nil {
+				log.Error("Invalid repo ID: %s", repoIDStr)
+				continue
+			}
 
-		tasks, err := models.FindRepoUndeliveredHookTasks(repoID)
-		if err != nil {
-			log.Error("Get repository [%d] hook tasks: %v", repoID, err)
-			continue
-		}
-		for _, t := range tasks {
-			if err = Deliver(t); err != nil {
-				log.Error("deliver: %v", err)
+			tasks, err := models.FindRepoUndeliveredHookTasks(repoID)
+			if err != nil {
+				log.Error("Get repository [%d] hook tasks: %v", repoID, err)
+				continue
+			}
+			for _, t := range tasks {
+				select {
+				case <-ctx.Done():
+					return
+				default:
+				}
+				if err = Deliver(t); err != nil {
+					log.Error("deliver: %v", err)
+				}
 			}
 		}
 	}
+
 }
 
 var (
@@ -234,5 +259,5 @@ func InitDeliverHooks() {
 		},
 	}
 
-	go DeliverHooks()
+	go graceful.GetManager().RunWithShutdownContext(DeliverHooks)
 }