Always refresh glanceclient for tokens validity

Glanceclient doesn't refresh tokens on its own. Work around this by
always making a new glanceclient with a potentialy new token if the
existing token is near expiration. This adds some overhead to our use of
glance but that is preferable to having glanceclient break because its
token has expired.

Change-Id: If57531a72eb90ee7bc6e67905ddfd5bda9bb6f1b

shade/__init__.py

@@ -556,25 +556,29 @@ class OpenStackCloud(object):
 
     @property
     def glance_client(self):
-        if self._glance_client is None:
-            token = self.auth_token
-            endpoint = self.get_session_endpoint('image')
-            glance_api_version = self._get_glance_api_version()
-            kwargs = dict()
-            if self.api_timeout is not None:
-                kwargs['timeout'] = self.api_timeout
-            try:
-                self._glance_client = glanceclient.Client(
-                    glance_api_version, endpoint, token=token,
-                    session=self.keystone_session,
-                    **kwargs)
-            except Exception as e:
-                self.log.debug("glance unknown issue", exc_info=True)
-                raise OpenStackCloudException(
-                    "Error in connecting to glance: %s" % str(e))
+        # Note that glanceclient doesn't use keystoneclient sessions
+        # which means that it won't make a new token if the old one has
+        # expired. Work around that by always making a new glanceclient here
+        # which may create a new token if the current one is close to
+        # expiration.
+        token = self.auth_token
+        endpoint = self.get_session_endpoint('image')
+        glance_api_version = self._get_glance_api_version()
+        kwargs = dict()
+        if self.api_timeout is not None:
+            kwargs['timeout'] = self.api_timeout
+        try:
+            self._glance_client = glanceclient.Client(
+                glance_api_version, endpoint, token=token,
+                session=self.keystone_session,
+                **kwargs)
+        except Exception as e:
+            self.log.debug("glance unknown issue", exc_info=True)
+            raise OpenStackCloudException(
+                "Error in connecting to glance: %s" % str(e))
 
-            if not self._glance_client:
-                raise OpenStackCloudException("Error connecting to glance")
+        if not self._glance_client:
+            raise OpenStackCloudException("Error connecting to glance")
         return self._glance_client
 
     @property