From fe6aeae7f4b5c367da1a30cd6e0db63603e67ad9 Mon Sep 17 00:00:00 2001
From: Chenxiong Qi <cqi@redhat.com>
Date: Nov 14 2016 02:23:33 +0000
Subject: Backwards compatible with krbV


Fix #139

Currently, python-gssapi is not available in EPEL, especially el6. This patch
is for the old version of OS to use krbV.

Signed-off-by: Chenxiong Qi <cqi@redhat.com>

---

diff --git a/pyrpkg/__init__.py b/pyrpkg/__init__.py
index 28a85a9..94374de 100644
--- a/pyrpkg/__init__.py
+++ b/pyrpkg/__init__.py
@@ -25,8 +25,6 @@ import six
 import sys
 import tempfile
 
-import gssapi
-
 from osbs.api import OSBS
 from osbs.conf import Configuration
 from six.moves import configparser
@@ -39,6 +37,20 @@ from pyrpkg.lookaside import CGILookasideCache
 from pyrpkg.sources import SourcesFile
 from pyrpkg.utils import cached_property, log_result
 
+try:
+    # Use gssapi to detect the Kerberos credential by default, even krbV is
+    # still available too.
+    import gssapi
+except ImportError:
+    gssapi = None
+
+try:
+    # This is for backwards compatibility in old version OS where gssapi is not
+    # available.
+    import krbV
+except ImportError:
+    krbV = None
+
 if sys.version_info[0:2] >= (2, 5):
     import subprocess
 else:
@@ -839,7 +851,7 @@ class Commands(object):
         return None
 
     # Define some helper functions, they start with _
-    def _has_krb_creds(self):
+    def _has_krb_creds_by_gssapi(self):
         """Test if there is usable initialized Kerberos credential
 
         :return: True if credential is initialized and not expired. Otherwise, False is returned.
@@ -858,6 +870,31 @@ class Commands(object):
             return False
         return True
 
+    def _has_krb_creds_by_krbv(self):
+        """Test if there is usable initialized Kerberos credential
+
+        :return: True if credential is initialized and not expired. Otherwise, False is returned.
+        :rtype: bool
+        """
+        try:
+            ctx = krbV.default_context()
+            ccache = ctx.default_ccache()
+            princ = ccache.principal()  # noqa
+            return True
+        except krbV.Krb5Error:
+            return False
+
+    def _has_krb_creds_default(self):
+        """Kerberos authentication is disabled if neither gssapi nor krbV is available"""
+        return False
+
+    if gssapi:
+        _has_krb_creds = _has_krb_creds_by_gssapi
+    elif krbV:
+        _has_krb_creds = _has_krb_creds_by_krbv
+    else:
+        _has_krb_creds = _has_krb_creds_default
+
     def _run_command(self, cmd, shell=False, env=None, pipe=[], cwd=None):
         """Run the given command.