fix 404 when requesting empty tripleo container image catalog

This patch adds graceful handling for requests against tripleo container
image catalog requests, before the catalog is populated / created.

Change-Id: I0834e095dacb44f0742a15ae67f64c72db7d9c54
Closes-Bug: 1825046
(cherry picked from commit 294f67bd7e)

tripleo_common/image/image_uploader.py

@@ -494,7 +494,16 @@ class BaseImageUploader(object):
         catalog_url = self._build_url(
             url, CALL_CATALOG
         )
-        catalog = session.get(catalog_url, timeout=30).json()
+        catalog_resp = session.get(catalog_url, timeout=30)
+        if catalog_resp.status_code in [200]:
+            catalog = catalog_resp.json()
+        elif catalog_resp.status_code in [404]:
+            catalog = {}
+        else:
+            raise ImageUploaderException(
+                'Image registry made invalid response: %s' %
+                (catalog_resp.status_code)
+            )
 
         tags_get_args = []
         for repo in catalog.get('repositories', []):

tripleo_common/tests/image/test_image_uploader.py

@@ -762,9 +762,12 @@ class TestBaseImageUploader(base.TestCase):
             ('localhost:8787/t/bink', [])
         )
         session = mock.Mock()
-        session.get.return_value.json.return_value = {
+        response = mock.Mock()
+        response.status_code = 200
+        response.json.return_value = {
             'repositories': ['t/foo', 't/bar', 't/baz', 't/bink']
         }
+        session.get.return_value = response
         self.assertEqual(
             [
                 'localhost:8787/t/foo:a',
@@ -783,6 +786,34 @@ class TestBaseImageUploader(base.TestCase):
                 (self.uploader, 'localhost:8787/t/bink', session)
             ])
 
+    @mock.patch('concurrent.futures.ThreadPoolExecutor')
+    def test_list_404(self, mock_pool):
+        # setup bits
+        session = mock.Mock()
+        response = mock.Mock()
+        response.status_code = 404
+        session.get.return_value = response
+        mock_pool.return_value.map.return_value = ()
+        # execute function
+        return_val = self.uploader.list('localhost:8787', session=session)
+        # check status of things
+        self.assertEqual(
+            [],
+            return_val
+        )
+
+    @mock.patch('concurrent.futures.ThreadPoolExecutor')
+    def test_list_500(self, mock_pool):
+        session = mock.Mock()
+        response = mock.Mock()
+        response.status_code = 500
+        session.get.return_value = response
+        mock_pool.return_value.map.return_value = ()
+        self.assertRaises(ImageUploaderException,
+                          self.uploader.list,
+                          'localhost:8787',
+                          session=session)
+
     def test_tags_for_image(self):
         session = mock.Mock()
         r = mock.Mock()