Graceful: Cancel Process on monitor pages & HammerTime (#9213)

* Graceful: Create callbacks to with contexts

* Graceful: Say when Gitea is completely finished

* Graceful: Git and Process within HammerTime

Force all git commands to terminate at HammerTime
Force all process commands to terminate at HammerTime
Move almost all git processes to run as git Commands

* Graceful: Always Hammer after Shutdown

* ProcessManager: Add cancel functionality

* Fix tests

* Make sure that process.Manager.Kill() cancels

* Make threadsafe access to Processes and remove own unused Kill

* Remove cmd from the process manager as it is no longer used

* the default context is the correct context

* get rid of double till

1 files changed, 107 insertions, 1 deletions

diff --git a/modules/graceful/manager.go b/modules/graceful/manager.go
index 48f76635ff..b9a56ca9c6 100644
--- a/modules/graceful/manager.go
+++ b/modules/graceful/manager.go
@@ -5,9 +5,12 @@
 package graceful
 
 import (
+	"context"
 	"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"
 )
 
@@ -34,9 +37,110 @@ const numberOfServersToCreate = 3
 var Manager *gracefulManager
 
 func init() {
-	Manager = newGracefulManager()
+	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()
 }
 
+// CallbackWithContext is combined runnable and context to watch to see if the caller has finished
+type CallbackWithContext func(ctx context.Context, callback func())
+
+// RunnableWithShutdownFns is a runnable with functions to run at shutdown and terminate
+// After the callback to atShutdown is called and is complete, the main function must return.
+// Similarly the callback function provided to atTerminate must return once termination is complete.
+// 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.
+type RunnableWithShutdownFns func(atShutdown, atTerminate func(context.Context, func()))
+
+// RunWithShutdownFns takes a function that has both atShutdown and atTerminate callbacks
+// After the callback to atShutdown is called and is complete, the main function must return.
+// Similarly the callback function provided to atTerminate must return once termination is complete.
+// 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) {
+	g.runningServerWaitGroup.Add(1)
+	defer g.runningServerWaitGroup.Done()
+	run(func(ctx context.Context, atShutdown func()) {
+		go func() {
+			select {
+			case <-g.IsShutdown():
+				atShutdown()
+			case <-ctx.Done():
+				return
+			}
+		}()
+	}, func(ctx context.Context, atTerminate func()) {
+		g.RunAtTerminate(ctx, atTerminate)
+	})
+}
+
+// RunnableWithShutdownChan is a runnable with functions to run at shutdown and terminate.
+// After the atShutdown channel is closed, the main function must return once shutdown is complete.
+// (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.
+type RunnableWithShutdownChan func(atShutdown <-chan struct{}, atTerminate CallbackWithContext)
+
+// RunWithShutdownChan takes a function that has channel to watch for shutdown and atTerminate callbacks
+// After the atShutdown channel is closed, the main function must return once shutdown is complete.
+// (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) {
+	g.runningServerWaitGroup.Add(1)
+	defer g.runningServerWaitGroup.Done()
+	run(g.IsShutdown(), func(ctx context.Context, atTerminate func()) {
+		g.RunAtTerminate(ctx, atTerminate)
+	})
+}
+
+// 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)) {
+	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()) {
+	g.terminateWaitGroup.Add(1)
+	go func() {
+		select {
+		case <-g.IsTerminate():
+			terminate()
+		case <-ctx.Done():
+		}
+		g.terminateWaitGroup.Done()
+	}()
+}
+
+// RunAtShutdown creates a go-routine to run the provided function at shutdown
+func (g *gracefulManager) RunAtShutdown(ctx context.Context, shutdown func()) {
+	go func() {
+		select {
+		case <-g.IsShutdown():
+			shutdown()
+		case <-ctx.Done():
+		}
+	}()
+}
+
+// RunAtHammer creates a go-routine to run the provided function at shutdown
+func (g *gracefulManager) RunAtHammer(ctx context.Context, hammer func()) {
+	go func() {
+		select {
+		case <-g.IsHammer():
+			hammer()
+		case <-ctx.Done():
+		}
+	}()
+}
 func (g *gracefulManager) doShutdown() {
 	if !g.setStateTransition(stateRunning, stateShuttingDown) {
 		return
@@ -50,6 +154,8 @@ func (g *gracefulManager) doShutdown() {
 	}
 	go func() {
 		g.WaitForServers()
+		// Mop up any remaining unclosed events.
+		g.doHammerTime(0)
 		<-time.After(1 * time.Second)
 		g.doTerminate()
 	}()