{Issue #47} Synchronous spinner

halo/halo.py

@@ -31,7 +31,8 @@ class Halo(object):
     SPINNER_PLACEMENTS = ('left', 'right',)
 
     def __init__(self, text='', color='cyan', text_color=None, spinner=None,
-                 animation=None, placement='left', interval=-1, enabled=True, stream=sys.stdout):
+                 animation=None, placement='left', interval=-1, enabled=True,
+                 manual_step=False, stream=sys.stdout):
         """Constructs the Halo object.
         Parameters
         ----------
@@ -59,6 +60,7 @@ def __init__(self, text='', color='cyan', text_color=None, spinner=None,
         """
         self._color = color
         self._animation = animation
+        self.manual_step = manual_step
 
         self.spinner = spinner
         self.text = text
@@ -72,6 +74,7 @@ def __init__(self, text='', color='cyan', text_color=None, spinner=None,
         self._text_index = 0
         self._spinner_thread = None
         self._stop_spinner = None
+        self._run_spinner = None
         self._spinner_id = None
         self.enabled = enabled
 
@@ -396,10 +399,24 @@ def render(self):
         self
         """
         while not self._stop_spinner.is_set():
-            self._render_frame()
+            if self._run_spinner.is_set():
+                self._render_frame()
+                if self.manual_step:
+                    self._run_spinner.clear()
             time.sleep(0.001 * self._interval)
 
         return self
+
+    def step(self):
+        """Runs the render once.
+        Returns
+        -------
+        self
+        """
+        if self._spinner_thread and self._spinner_thread.is_alive():
+            self._run_spinner.set()
+
+        return self
 
     def frame(self):
         """Builds and returns the frame to be rendered
@@ -469,9 +486,12 @@ def start(self, text=None):
         self._hide_cursor()
 
         self._stop_spinner = threading.Event()
+        self._run_spinner = threading.Event()
         self._spinner_thread = threading.Thread(target=self.render)
         self._spinner_thread.setDaemon(True)
-        self._render_frame()
+        if not self.manual_step:
+            self._render_frame()
+            self._run_spinner.set()
         self._spinner_id = self._spinner_thread.name
         self._spinner_thread.start()
 

halo/halo_notebook.py

@@ -10,15 +10,18 @@
 
 
 class HaloNotebook(Halo):
-    def __init__(self, text='', color='cyan', text_color=None, spinner=None, placement='left',
-                 animation=None, interval=-1, enabled=True, stream=sys.stdout):
+    def __init__(self, text='', color='cyan', text_color=None, spinner=None,
+                 placement='left', animation=None, interval=-1, enabled=True,
+                 manual_step=False, stream=sys.stdout):
         super(HaloNotebook, self).__init__(text=text,
                                            color=color,
                                            text_color=text_color,
                                            spinner=spinner,
                                            placement=placement,
                                            animation=animation,
-                                           interval=interval, enabled=enabled,
+                                           interval=interval,
+                                           enabled=enabled,
+                                           manual_step=manual_step,
                                            stream=stream)
         self.output = self._make_output_widget()
 
@@ -62,9 +65,12 @@ def start(self, text=None):
 
         display(self.output)
         self._stop_spinner = threading.Event()
+        self._run_spinner = threading.Event()
         self._spinner_thread = threading.Thread(target=self.render)
         self._spinner_thread.setDaemon(True)
-        self._render_frame()
+        if not self.manual_step:
+            self._render_frame()
+            self._run_spinner.set()
         self._spinner_id = self._spinner_thread.name
         self._spinner_thread.start()
 

tests/test_halo.py

@@ -621,6 +621,28 @@ def test_redirect_stdout(self):
             self._stream = out
 
         self.assertIn('foo', output[0])
+
+    def test_manual_step(self):
+        """Test manual step
+        """
+        default_spinner = Halo()
+        self.assertEqual(default_spinner.manual_step, False)
+        manual_spinner = Halo(spinner='dots', manual_step=True,
+                              stream=self._stream)
+
+        texts = ['foo', 'bar', 'baz']
+
+        manual_spinner.start()
+        for text in texts:
+            manual_spinner.text=text
+            manual_spinner.step()
+            time.sleep(1)
+        manual_spinner.stop()
+        output = self._get_test_output()['text']
+
+        self.assertEqual(output[0], '{} {}'.format(frames[0], texts[0]))
+        self.assertEqual(output[1], '{} {}'.format(frames[1], texts[1]))
+        self.assertEqual(output[2], '{} {}'.format(frames[2], texts[2]))
 
     def tearDown(self):
         pass