feat(process): add Core stdin task

actions.go

@@ -82,6 +82,18 @@ type TaskProcessOutput struct {
 	ID string
 }
 
+// TaskProcessInput writes data to the stdin of a managed process through Core.PERFORM.
+//
+// Example:
+//
+//	c.PERFORM(process.TaskProcessInput{ID: "proc-1", Input: "hello\n"})
+type TaskProcessInput struct {
+	// ID identifies a managed process started by this service.
+	ID string
+	// Input is written verbatim to the process stdin pipe.
+	Input string
+}
+
 // TaskProcessList requests a snapshot of managed processes through Core.PERFORM.
 // If RunningOnly is true, only active processes are returned.
 //

service.go

@@ -624,6 +624,21 @@ func (s *Service) handleTask(c *core.Core, task core.Task) core.Result {
 		}
 
 		return core.Result{Value: output, OK: true}
+	case TaskProcessInput:
+		if m.ID == "" {
+			return core.Result{Value: coreerr.E("Service.handleTask", "task process input requires an id", nil), OK: false}
+		}
+
+		proc, err := s.Get(m.ID)
+		if err != nil {
+			return core.Result{Value: err, OK: false}
+		}
+
+		if err := proc.SendInput(m.Input); err != nil {
+			return core.Result{Value: err, OK: false}
+		}
+
+		return core.Result{OK: true}
 	case TaskProcessList:
 		procs := s.List()
 		if m.RunningOnly {

service_test.go

@@ -753,6 +753,29 @@ func TestService_OnStartup(t *testing.T) {
 		require.True(t, ok)
 		assert.Contains(t, output, "snapshot-output")
 	})
+
+	t.Run("registers process.input task", func(t *testing.T) {
+		svc, c := newTestService(t)
+
+		err := svc.OnStartup(context.Background())
+		require.NoError(t, err)
+
+		proc, err := svc.Start(context.Background(), "cat")
+		require.NoError(t, err)
+
+		result := c.PERFORM(TaskProcessInput{
+			ID:    proc.ID,
+			Input: "typed-through-core\n",
+		})
+		require.True(t, result.OK)
+
+		err = proc.CloseStdin()
+		require.NoError(t, err)
+
+		<-proc.Done()
+
+		assert.Contains(t, proc.Output(), "typed-through-core")
+	})
 }
 
 func TestService_RunWithOptions(t *testing.T) {