Direct download for object storage

PCI-32289

glanceclient/v2/images.py

@@ -16,6 +16,7 @@
 import hashlib
 import json
 from oslo_utils import encodeutils
+from oslo_log import log as logging
 from requests import codes
 import urllib.parse
 import warlock
@@ -24,6 +25,8 @@ from glanceclient.common import utils
 from glanceclient import exc
 from glanceclient.v2 import schemas
 
+LOG = logging.getLogger(__name__)
+
 DEFAULT_PAGE_SIZE = 200
 
 SORT_DIR_VALUES = ('asc', 'desc')
@@ -216,7 +219,12 @@ class Controller(object):
                 'This operation is not supported by Glance.')
 
     @utils.add_req_id_to_object()
-    def data(self, image_id, do_checksum=True, allow_md5_fallback=False):
+    def data(self,
+             image_id,
+             do_checksum=True,
+             allow_md5_fallback=False,
+             direct_download=False,
+             ):
         """Retrieve data of an image.
 
         When do_checksum is enabled, validation proceeds as follows:
@@ -251,13 +259,34 @@ class Controller(object):
             meta_hash_value = image_meta.get('os_hash_value', None)
             meta_hash_algo = image_meta.get('os_hash_algo', None)
 
-        url = '/v2/images/%s/file' % image_id
-        resp, body = self.http_client.get(url)
-        if resp.status_code == codes.no_content:
-            return None, resp
+        file_fallback = False
+        if direct_download:
+            url = '/v2/images/%s/direct-download' % image_id
+            try:
+                resp, body = self.http_client.get(url)
+            except exc.HTTPNotImplemented:
+                LOG.warn("Direct download for %s failed, falling back to "
+                         "download from Glance", image_id)
+                file_fallback = True
+            except exc.HTTPForbidden as e:
+                LOG.warn("Error while direct downloading %s: %s", image_id, e)
+                raise e
+            else:
+                if resp.status_code == codes.no_content:
+                    return None, resp
+
+        if not direct_download or file_fallback:
+            url = '/v2/images/%s/file' % image_id
+            resp, body = self.http_client.get(url)
+            if resp.status_code == codes.no_content:
+                return None, resp
 
         checksum = resp.headers.get('content-md5', None)
-        content_length = int(resp.headers.get('content-length', 0))
+        content_length = 0
+        if 'content-length' in resp.headers:
+            content_length = int(resp.headers['content-length'])
+        elif 'Content-Length' in resp.headers:
+            content_length = int(resp.headers['Content-Length'])
 
         check_md5sum = do_checksum
         if do_checksum and meta_hash_value is not None: