Add pause resume and abort controls

internal/restic/restic.go

@@ -12,6 +12,8 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strings"
+	"sync"
+	"syscall"
 
 	"github.com/backupper-unraid/backupper/internal/model"
 )
@@ -23,6 +25,47 @@ type Runner struct {
 	RuntimeDir string
 	Secrets    SecretGetter
 	Log        *slog.Logger
+	mu         sync.Mutex
+	processes  map[string]*os.Process
+}
+
+type runIDKey struct{}
+
+func WithRunID(ctx context.Context, runID string) context.Context {
+	return context.WithValue(ctx, runIDKey{}, runID)
+}
+
+func (r *Runner) Pause(runID string) error  { return r.signal(runID, syscall.SIGSTOP) }
+func (r *Runner) Resume(runID string) error { return r.signal(runID, syscall.SIGCONT) }
+
+func (r *Runner) signal(runID string, signal syscall.Signal) error {
+	r.mu.Lock()
+	process := r.processes[runID]
+	r.mu.Unlock()
+	if process == nil {
+		return errors.New("restic process is not active yet")
+	}
+	if err := syscall.Kill(-process.Pid, signal); err != nil {
+		return fmt.Errorf("signal restic process group: %w", err)
+	}
+	return nil
+}
+
+func (r *Runner) registerProcess(runID string, process *os.Process) func() {
+	if runID == "" {
+		return func() {}
+	}
+	r.mu.Lock()
+	if r.processes == nil {
+		r.processes = make(map[string]*os.Process)
+	}
+	r.processes[runID] = process
+	r.mu.Unlock()
+	return func() {
+		r.mu.Lock()
+		delete(r.processes, runID)
+		r.mu.Unlock()
+	}
 }
 
 type Summary struct {
@@ -203,6 +246,19 @@ func (r *Runner) run(ctx context.Context, repo model.Repository, args []string,
 	}
 	fullArgs := append(globalArgs, args...)
 	cmd := exec.CommandContext(ctx, r.Binary, fullArgs...)
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	cmd.Cancel = func() error {
+		if cmd.Process == nil {
+			return os.ErrProcessDone
+		}
+		if err := syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL); err != nil {
+			if errors.Is(err, syscall.ESRCH) {
+				return os.ErrProcessDone
+			}
+			return err
+		}
+		return nil
+	}
 	cmd.Env = []string{"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", "HOME=/root", "RESTIC_PASSWORD_FILE=" + passwordPath}
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
@@ -215,6 +271,9 @@ func (r *Runner) run(ctx context.Context, repo model.Repository, args []string,
 	if err := cmd.Start(); err != nil {
 		return classify(err)
 	}
+	runID, _ := ctx.Value(runIDKey{}).(string)
+	unregister := r.registerProcess(runID, cmd.Process)
+	defer unregister()
 	var captured []byte
 	done := make(chan struct{})
 	go func() {