openstack
/
nova
Code Issues Proposed changes

Clean up header encoding handling in compute API 

PEP 3333[1] says request and response headers (within the application)
should be treated as native `str` (whatever the Python version). It's
the job of the WSGI server to translate from `str` to reasonable output
on the outgoing socket connection.

This was already mostly correct but two issues were discovered while
trying to create integration tests that use the value of the location
response header when POSTing to create a server. In python2 it was
working. In Python3 the header had a value of

location: http://192.168.1.76/compute/v2.1/b'http:/192.168.1.76/compute/v2.1/servers/fad04042-850b-443a-9e48-773111cbc981'

(note the b'...' bounding the full url on the end).

This was happening for two reasons:

* nova/api/openstack/compute/servers.py independently encodes the
  location header to utf-8, instead of using the centralized handling
  in nova/api/openstack/wsgi.py

  This meant that the value of the location header would arrive, in
  Python 3, at the centralized handling as a bytestring.

* The centralized handling in nova/api/openstack/wsgi.py was incorrectly
  using the six.text_type() method. That is simply an alias to unicode
  in python 2 and str in python3. In python3 when given a bytestring
  as the only argument object.__str()__ is called on the argument.
  Which yields b'whatever'.

At that stage, the handling in the web server which processes a location
header to check for the presence of a host and prefix already at the
start of the provided location will find b'...' and do a concatenation
without any replace.

So, because of all that, this patch includes three changes:

* The server creation location header code does no encoding and relies
  on the centralized handling.

* The centralized handling removes the use of text_type() as a function
  because that is redundant with the safe_encode and safe_decode changes
  in the same loop.

* Doc strings and comments in the ResponseObject are clarified with
  regard to this encoding topic.

Also, comments in Resource._process_stack are updated to correspond with
the changes above. The code is not changed, as they are already doing
the right thing: The comment was misrepresenting what was going on.
There is some duplication of code between these two areas, but the code
is too inscrutable for me to be willing to change a part that isn't
presenting an explicit bug.

Tests for the internal production of the location header are adjusted
to reflect these changes.

[1] https://www.python.org/dev/peps/pep-3333/#a-note-on-string-types

Change-Id: I163c417375678b428ac77aac87ccafaf1f6186ab
Closes-Bug: #1795425
This commit is contained in:
Chris Dent 2018-10-01 15:56:05 +01:00
parent 5f648dda49
commit 68a689b0f3
3 changed files with 18 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
nova/api/openstack/compute/servers.py
View File

@ -67,7 +67,7 @@ class ServersController(wsgi.Controller):
link = [l for l in robj.obj['server']['links'] if l['rel'] == 'self']
if link:
robj['Location'] = utils.utf8(link[0]['href'])
robj['Location'] = link[0]['href']
# Convenience return
return robj

19
nova/api/openstack/wsgi.py
View File

@ -261,6 +261,9 @@ class ResponseObject(object):
Utility method for serializing the wrapped object. Returns a
webob.Response object.
Header values are set to the appropriate Python type and
encoding demanded by PEP 3333: whatever the native str type is.
"""
serializer = self.serializer
@ -271,24 +274,24 @@ class ResponseObject(object):
response = webob.Response(body=body)
response.status_int = self.code
for hdr, val in self._headers.items():
if not isinstance(val, six.text_type):
val = six.text_type(val)
if six.PY2:
# In Py2.X Headers must be byte strings
# In Py2.X Headers must be a UTF-8 encode str.
response.headers[hdr] = encodeutils.safe_encode(val)
else:
# In Py3.X Headers must be utf-8 strings
# In Py3.X Headers must be a str that was first safely
# encoded to UTF-8 (to catch any bad encodings) and then
# decoded back to a native str.
response.headers[hdr] = encodeutils.safe_decode(
encodeutils.safe_encode(val))
# Deal with content_type
if not isinstance(content_type, six.text_type):
content_type = six.text_type(content_type)
if six.PY2:
# In Py2.X Headers must be byte strings
# In Py2.X Headers must be a UTF-8 encode str.
response.headers['Content-Type'] = encodeutils.safe_encode(
content_type)
else:
# In Py3.X Headers must be utf-8 strings
# In Py3.X Headers must be a str.
response.headers['Content-Type'] = encodeutils.safe_decode(
encodeutils.safe_encode(content_type))
return response
@ -558,10 +561,10 @@ class Resource(wsgi.Application):
if not isinstance(val, six.text_type):
val = six.text_type(val)
if six.PY2:
# In Py2.X Headers must be byte strings
# In Py2.X Headers must be UTF-8 encoded string
response.headers[hdr] = encodeutils.safe_encode(val)
else:
# In Py3.X Headers must be utf-8 strings
# In Py3.X Headers must be a string
response.headers[hdr] = encodeutils.safe_decode(
encodeutils.safe_encode(val))

8
nova/tests/unit/api/openstack/compute/test_server_actions.py
View File

@ -289,7 +289,9 @@ class ServerActionsControllerTestV21(test.TestCase):
self.assertEqual(len(body['server']['adminPass']),
CONF.password_length)
self.assertEqual(robj['location'], self_href.encode('utf-8'))
self.assertEqual(robj['location'], self_href)
# pep3333 requires applications produces headers which are str
self.assertEqual(str, type(robj['location']))
def test_rebuild_instance_with_image_uuid(self):
info = dict(image_href_in_call=None)
@ -343,7 +345,9 @@ class ServerActionsControllerTestV21(test.TestCase):
self.assertEqual(body['server']['image']['id'], '2')
self.assertNotIn("adminPass", body['server'])
self.assertEqual(robj['location'], self_href.encode('utf-8'))
self.assertEqual(robj['location'], self_href)
# pep3333 requires applications produces headers which are str
self.assertEqual(str, type(robj['location']))
def test_rebuild_raises_conflict_on_invalid_state(self):
body = {