Direct download

glanceclient/common/http.py

@@ -288,3 +288,39 @@ def _close_after_stream(response, chunk_size):
     # This will return the connection to the HTTPConnectionPool in urllib3
     # and ideally reduce the number of HTTPConnectionPool full warnings.
     response.close()
+
+def direct_download_from_link(direct_link, chunk_size=CHUNKSIZE):
+    session = requests.Session()
+    session.headers["User-Agent"] = USER_AGENT
+    try:
+        resp = session.request('GET', direct_link, stream=True)
+    except requests.exceptions.Timeout as e:
+        message = ("Error communicating with %(url)s: %(e)s" %
+                   dict(url=direct_link, e=e))
+        raise exc.InvalidEndpoint(message=message)
+    except (requests.exceptions.ConnectionError, ProtocolError) as e:
+        message = ("Error finding address  for %(url)s: %(e)s" %
+                   dict(url=direct_link, e=e))
+        raise exc.CommunicationError(message=message)
+    except socket.gaierror as e:
+        message = "Error finding address for %s: %s" % (
+            direct_link, e)
+        raise exc.InvalidEndpoint(message=message)
+    except (socket.error, socket.timeout) as e:
+        endpoint = self.endpoint
+        message = ("Error communicating with %(endpoint)s %(e)s" %
+                   {'endpoint': direct_link, 'e': e})
+        raise exc.CommunicationError(message=message)
+
+    resp, body_iter = _direct_download_handle_response(resp, chunk_size)
+    HTTPClient.log_http_response(resp)
+    return resp, body_iter
+
+def _direct_download_handle_response(resp, chunk_size=CHUNKSIZE):
+        if not resp.ok:
+            LOG.debug("Request returned failure status %s." % resp.status_code)
+            raise exc.from_response(resp, resp.content)
+        # Read body into string if it isn't obviously image data
+        body_iter = _close_after_stream(resp, chunk_size)
+        return resp, body_iter
+

glanceclient/v2/images.py

@@ -21,6 +21,7 @@
 import warlock
 
 from glanceclient.common import utils
+from glanceclient.common import http
 from glanceclient import exc
 from glanceclient.v2 import schemas
 
@@ -195,6 +196,33 @@ def data(self, image_id, do_checksum=True):
 
         return utils.IterableWithLength(body, content_length)
 
+    def get_link(self, image_id):
+        url = '/v2/images/%s/link' % image_id
+        resp, body = self.http_client.get(url)
+        return self.model(**body)
+
+    def data_direct_download(self, image_id, do_checksum=True, chunk_size=64*1024):
+        """Retrieve data of an image without overloading glance server (using direct download link of the image)
+
+        :param image_id:    ID of the image to download.
+        :param do_checksum: Enable/disable checksum validation.
+        Similar to data but get the link to image and download on its own.
+        """
+        url = 'v2/images/%s/link' % image_id
+        resp, body  = self.http_client.get(url)
+        direct_link = body.get('image_path', None)
+        checksum    = body.get('image_checksum', None)
+
+        if not direct_link:
+            raise Exception("Image '%s' does not have a valid direct download path" % image_id)
+
+        resp, body      = http.direct_download_from_link(direct_link, chunk_size)
+        content_length  = int(resp.headers.get('content-length', 0))
+
+        if do_checksum and checksum is not None:
+            body = utils.integrity_iter(body, checksum)
+        return utils.IterableWithLength(body, content_length)
+
     def upload(self, image_id, image_data, image_size=None):
         """
         Upload the data for an image.