remove glance usage inside compute

refactor compute code to remove glance direct usage,
1) use image_api.get instead of get glance code then show the image
detail information
2) according to TODO, create a new api in image.api and use it

Change-Id: I0c8dee5d0d18adeaa83183da81c85f378ae5f8fd

nova/compute/manager.py

@@ -74,7 +74,6 @@ from nova import exception_wrapper
 from nova import hooks
 from nova.i18n import _
 from nova import image
-from nova.image import glance
 from nova import manager
 from nova import network
 from nova.network import base_api as base_net_api
@@ -2974,8 +2973,8 @@ class ComputeManager(manager.Manager):
         # This instance.exists message should contain the original
         # image_ref, not the new one.  Since the DB has been updated
         # to point to the new one... we have to override it.
-        # TODO(jaypipes): Move generate_image_url() into the nova.image.api
+        orig_image_ref_url = self.image_api.generate_image_url(orig_image_ref,
-        orig_image_ref_url = glance.generate_image_url(orig_image_ref, context)
+                                                               context)
         extra_usage_info = {'image_ref_url': orig_image_ref_url}
         compute_utils.notify_usage_exists(
                 self.notifier, context, instance,
@@ -3307,10 +3306,9 @@ class ComputeManager(manager.Manager):
             msg = 'Instance disappeared during snapshot'
             LOG.debug(msg, instance=instance)
             try:
-                image_service = glance.get_default_image_service()
+                image = self.image_api.get(context, image_id)
-                image = image_service.show(context, image_id)
                 if image['status'] != 'active':
-                    image_service.delete(context, image_id)
+                    self.image_api.delete(context, image_id)
             except Exception:
                 LOG.warning("Error while trying to clean up image %s",
                             image_id, instance=instance)

nova/image/api.py

@@ -55,6 +55,16 @@ class API(object):
         #                 the context alive...
         return glance.get_default_image_service()
 
+    @staticmethod
+    def generate_image_url(image_ref, context):
+        """Generate an image URL from an image_ref.
+
+        :param image_ref: The image ref to generate URL
+        :param context: The `nova.context.Context` object for the request
+        """
+        return "%s/images/%s" % (next(glance.get_api_servers(context)),
+                                 image_ref)
+
     def get_all(self, context, **kwargs):
         """Retrieves all information records about all disk images available
         to show to the requesting user. If the requesting user is an admin,

nova/tests/unit/compute/test_compute_mgr.py

@@ -6574,13 +6574,16 @@ class ComputeManagerMigrationTestCase(test.NoDBTestCase):
         migration.status = 'running'
         migration.id = 0
 
+        # TODO(jichenjc): will be removed when remove glance.generate_image_url
         @mock.patch('nova.image.glance.generate_image_url',
                     return_value='fake-url')
+        @mock.patch('nova.image.api.API.generate_image_url',
+                    return_value='fake-url')
         @mock.patch.object(objects.Migration, 'get_by_id',
                            return_value=migration)
         @mock.patch.object(self.compute.driver,
                            'live_migration_force_complete')
-        def _do_test(force_complete, get_by_id, gen_img_url):
+        def _do_test(force_complete, get_by_id, gen_img_url, glance_image_url):
             self.compute.live_migration_force_complete(
                 self.context, self.instance, migration.id)