API: accept None as content-length in HTTP requests

The API defines PUT and POST as HTTP methods which need a request body.
It is allowed, that this request body might be of zero length. What was
missing is, that the "content-length" of the request also might be None.

The tempest test cases of servers.test_server_tags.ServerTagsTestJSON
revealed that a PUT with a non-existing body raises a BadRequest exception
because of the missing "content-length".

  [tempest.lib.common.rest_client]
  Request - Headers:
  {'Content-Type': 'application/json', 'Accept': 'application/json',
  'X-OpenStack-Nova-API-Version': '2.26', 'X-Auth-Token': '<omitted>'}
  Body: None

  Response - Headers: {'status': '400', u'content-length': '66',
  u'server': 'Apache/2.4.6 (CentOS)
              OpenSSL/1.0.1e-fips mod_wsgi/3.4 Python/2.7.5',
  u'date': 'Mon, 03 Apr 2017 10:15:12 GMT',
  u'x-openstack-nova-api-version': '2.26',
  u'x-compute-request-id': 'req-1f8726fc-df20-4592-a214-cff3fa73c8e6',
  u'content-type': 'application/json; charset=UTF-8',
  content-location': 'https://ctrl:8774/v2.1/servers/<uuid>/tags/mytag',
  u'vary': 'OpenStack-API-Version,X-OpenStack-Nova-API-Version',
  u'openstack-api-version': 'compute 2.26',
  u'connection': 'close'}
  Body: {"badRequest":
          {"message": "Malformed request body", "code": 400}
        }

For some reason this, this seems to only occur on centos7 test nodes,
but not on ubuntu xenial nodes. The root cause is still unclear to me.
I suspect the underlying "webob.Request" object which is used in Nova's
API, but I don't have proof for that.

This change checks for "content-length is None". The logic to determine the
request content was part of a very long method which is hard to test. That's
why I extracted the code paths to a new method. That made the unit test much
easier.

Change I3236648f79f44d2758bb7ab0d64d58b0143f6bdb alters the tempest test
cases which revealed the missing handling of "content-length is None".

Change-Id: Id0b0ab5050a4ec15ab2a0d0dd67fcefe4b1ecb39
Closes-Bug: #1679223

1 files changed, 11 insertions, 7 deletions

diff --git a/nova/api/openstack/wsgi.py b/nova/api/openstack/wsgi.py
index 1144400c34..73d37655c6 100644
--- a/nova/api/openstack/wsgi.py
+++ b/nova/api/openstack/wsgi.py
@@ -625,13 +625,7 @@ class Resource(wsgi.Application):
 
         # Now, deserialize the request body...
         try:
-            contents = {}
-            if self._should_have_body(request):
-                # allow empty body with PUT and POST
-                if request.content_length == 0:
-                    contents = {'body': None}
-                else:
-                    contents = self.deserialize(body)
+            contents = self._get_request_content(body, request)
         except exception.MalformedRequestBody:
             msg = _("Malformed request body")
             return Fault(webob.exc.HTTPBadRequest(explanation=msg))
@@ -699,6 +693,16 @@ class Resource(wsgi.Application):
 
         return response
 
+    def _get_request_content(self, body, request):
+        contents = {}
+        if self._should_have_body(request):
+            # allow empty body with PUT and POST
+            if request.content_length == 0 or request.content_length is None:
+                contents = {'body': None}
+            else:
+                contents = self.deserialize(body)
+        return contents
+
     def get_method(self, request, action, content_type, body):
         meth, extensions = self._get_method(request,
                                             action,