Possible division by zero error when pulling an image - fixes #1463

Signed-off-by: Todd Whiteman <todd.whiteman@joyent.com>

compose/progress_stream.py

@@ -74,8 +74,9 @@ def print_output_event(event, stream, is_terminal):
         stream.write("%s %s%s" % (status, event['progress'], terminator))
     elif 'progressDetail' in event:
         detail = event['progressDetail']
-        if 'current' in detail:
-            percentage = float(detail['current']) / float(detail['total']) * 100
+        total = detail.get('total')
+        if 'current' in detail and total:
+            percentage = float(detail['current']) / float(total) * 100
             stream.write('%s (%.1f%%)%s' % (status, percentage, terminator))
         else:
             stream.write('%s%s' % (status, terminator))

tests/unit/progress_stream_test.py

@@ -17,3 +17,21 @@ class ProgressStreamTestCase(unittest.TestCase):
         ]
         events = progress_stream.stream_output(output, StringIO())
         self.assertEqual(len(events), 1)
+
+    def test_stream_output_div_zero(self):
+        output = [
+            '{"status": "Downloading", "progressDetail": {"current": '
+            '0, "start": 1413653874, "total": 0}, '
+            '"progress": "..."}',
+        ]
+        events = progress_stream.stream_output(output, StringIO())
+        self.assertEqual(len(events), 1)
+
+    def test_stream_output_null_total(self):
+        output = [
+            '{"status": "Downloading", "progressDetail": {"current": '
+            '0, "start": 1413653874, "total": null}, '
+            '"progress": "..."}',
+        ]
+        events = progress_stream.stream_output(output, StringIO())
+        self.assertEqual(len(events), 1)