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, 47 insertions, 26 deletions

diff --git a/modules/process/manager.go b/modules/process/manager.go
index 3e77c0a6a9..af6ee9b81d 100644
--- a/modules/process/manager.go
+++ b/modules/process/manager.go
@@ -12,6 +12,7 @@ import (
 	"fmt"
 	"io"
 	"os/exec"
+	"sort"
 	"sync"
 	"time"
 )
@@ -24,14 +25,17 @@ var (
 	// ErrExecTimeout represent a timeout error
 	ErrExecTimeout = errors.New("Process execution timeout")
 	manager        *Manager
+
+	// DefaultContext is the default context to run processing commands in
+	DefaultContext = context.Background()
 )
 
-// Process represents a working process inherit from Gogs.
+// Process represents a working process inheriting from Gitea.
 type Process struct {
 	PID         int64 // Process ID, not system one.
 	Description string
 	Start       time.Time
-	Cmd         *exec.Cmd
+	Cancel      context.CancelFunc
 }
 
 // Manager knows about all processes and counts PIDs.
@@ -39,28 +43,28 @@ type Manager struct {
 	mutex sync.Mutex
 
 	counter   int64
-	Processes map[int64]*Process
+	processes map[int64]*Process
 }
 
 // GetManager returns a Manager and initializes one as singleton if there's none yet
 func GetManager() *Manager {
 	if manager == nil {
 		manager = &Manager{
-			Processes: make(map[int64]*Process),
+			processes: make(map[int64]*Process),
 		}
 	}
 	return manager
 }
 
 // Add a process to the ProcessManager and returns its PID.
-func (pm *Manager) Add(description string, cmd *exec.Cmd) int64 {
+func (pm *Manager) Add(description string, cancel context.CancelFunc) int64 {
 	pm.mutex.Lock()
 	pid := pm.counter + 1
-	pm.Processes[pid] = &Process{
+	pm.processes[pid] = &Process{
 		PID:         pid,
 		Description: description,
 		Start:       time.Now(),
-		Cmd:         cmd,
+		Cancel:      cancel,
 	}
 	pm.counter = pid
 	pm.mutex.Unlock()
@@ -71,10 +75,32 @@ func (pm *Manager) Add(description string, cmd *exec.Cmd) int64 {
 // Remove a process from the ProcessManager.
 func (pm *Manager) Remove(pid int64) {
 	pm.mutex.Lock()
-	delete(pm.Processes, pid)
+	delete(pm.processes, pid)
 	pm.mutex.Unlock()
 }
 
+// Cancel a process in the ProcessManager.
+func (pm *Manager) Cancel(pid int64) {
+	pm.mutex.Lock()
+	process, ok := pm.processes[pid]
+	pm.mutex.Unlock()
+	if ok {
+		process.Cancel()
+	}
+}
+
+// Processes gets the processes in a thread safe manner
+func (pm *Manager) Processes() []*Process {
+	pm.mutex.Lock()
+	processes := make([]*Process, 0, len(pm.processes))
+	for _, process := range pm.processes {
+		processes = append(processes, process)
+	}
+	pm.mutex.Unlock()
+	sort.Sort(processList(processes))
+	return processes
+}
+
 // Exec a command and use the default timeout.
 func (pm *Manager) Exec(desc, cmdName string, args ...string) (string, string, error) {
 	return pm.ExecDir(-1, "", desc, cmdName, args...)
@@ -110,7 +136,7 @@ func (pm *Manager) ExecDirEnvStdIn(timeout time.Duration, dir, desc string, env
 	stdOut := new(bytes.Buffer)
 	stdErr := new(bytes.Buffer)
 
-	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	ctx, cancel := context.WithTimeout(DefaultContext, timeout)
 	defer cancel()
 
 	cmd := exec.CommandContext(ctx, cmdName, args...)
@@ -126,7 +152,7 @@ func (pm *Manager) ExecDirEnvStdIn(timeout time.Duration, dir, desc string, env
 		return "", "", err
 	}
 
-	pid := pm.Add(desc, cmd)
+	pid := pm.Add(desc, cancel)
 	err := cmd.Wait()
 	pm.Remove(pid)
 
@@ -137,21 +163,16 @@ func (pm *Manager) ExecDirEnvStdIn(timeout time.Duration, dir, desc string, env
 	return stdOut.String(), stdErr.String(), err
 }
 
-// Kill and remove a process from list.
-func (pm *Manager) Kill(pid int64) error {
-	if proc, exists := pm.Processes[pid]; exists {
-		pm.mutex.Lock()
-		if proc.Cmd != nil &&
-			proc.Cmd.Process != nil &&
-			proc.Cmd.ProcessState != nil &&
-			!proc.Cmd.ProcessState.Exited() {
-			if err := proc.Cmd.Process.Kill(); err != nil {
-				return fmt.Errorf("failed to kill process(%d/%s): %v", pid, proc.Description, err)
-			}
-		}
-		delete(pm.Processes, pid)
-		pm.mutex.Unlock()
-	}
+type processList []*Process
+
+func (l processList) Len() int {
+	return len(l)
+}
+
+func (l processList) Less(i, j int) bool {
+	return l[i].PID < l[j].PID
+}
 
-	return nil
+func (l processList) Swap(i, j int) {
+	l[i], l[j] = l[j], l[i]
 }