Remove custom SSL compression handling

Custom SSL handling was introduced because disabling SSL layer compression
provided an approximately five fold performance increase in some
cases. Without SSL layer compression disabled the image transfer would be
CPU bound -- with the CPU performing the DEFLATE algorithm.  This would
typically limit image transfers to < 20 MB/s. When --no-ssl-compression
was specified the client would not negotiate any compression algorithm
during the SSL handshake with the server which would remove the CPU
bottleneck and transfers could approach wire speed.

In order to support '--no-ssl-compression' two totally separate code
paths exist depending on whether this is True or False.  When SSL
compression is disabled, rather than using the standard 'requests'
library, we enter some custom code based on pyopenssl and httplib in
order to disable compression.

This patch/spec proposes removing the custom code because:

* It is a burden to maintain

 Eg adding new code such as keystone session support is more complicated

* It can introduce additional failure modes

 We have seen some bugs related to the 'custom' certificate checking

* Newer Operating Systems disable SSL for us.

 Eg. While Debian 7 defaulted to compression 'on', Debian 8 has compression
 'off'. This makes both servers and client less likely to have compression
 enabled.

* Newer combinations of 'requests' and 'python' do this for us

 Requests disables compression when backed by a version of python which
 supports it (>= 2.7.9). This makes clients more likely to disable
 compression out-of-the-box.

* It is (in principle) possible to do this on older versions too

 If pyopenssl, ndg-httpsclient and pyasn1 are installed on older
 operating system/python combinations, the requests library should
 disable SSL compression on the client side.

* Systems that have SSL compression enabled may be vulnerable to the CRIME
(https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-4929) attack.
Installations which are security conscious should be running the Glance
server with SSL disabled.

Full Spec: https://review.openstack.org/#/c/187674
Blueprint: remove-custom-client-ssl-handling

Change-Id: I7e7761fc91b0d6da03939374eeedd809534f6edf

1 files changed, 0 insertions, 19 deletions

diff --git a/glanceclient/tests/unit/test_http.py b/glanceclient/tests/unit/test_http.py
index c7a16f3..bab91e5 100644
--- a/glanceclient/tests/unit/test_http.py
+++ b/glanceclient/tests/unit/test_http.py
@@ -29,8 +29,6 @@ import types
 
 import glanceclient
 from glanceclient.common import http
-from glanceclient.common import https
-from glanceclient import exc
 from glanceclient.tests import utils
 
 
@@ -354,20 +352,3 @@ class TestClient(testtools.TestCase):
         self.assertThat(mock_log.call_args[0][0],
                         matchers.Not(matchers.MatchesRegex(token_regex)),
                         'token found in LOG.debug parameter')
-
-
-class TestVerifiedHTTPSConnection(testtools.TestCase):
-    """Test fixture for glanceclient.common.http.VerifiedHTTPSConnection."""
-
-    def test_setcontext_unable_to_load_cacert(self):
-        """Add this UT case with Bug#1265730."""
-        self.assertRaises(exc.SSLConfigurationError,
-                          https.VerifiedHTTPSConnection,
-                          "127.0.0.1",
-                          None,
-                          None,
-                          None,
-                          "gx_cacert",
-                          None,
-                          False,
-                          True)