put kerberos config params in rida configuration

koji.read_config() filters out configuration options it doesn't know
about silently. Currently this is about the keytab, principal, ccache
options. The latter may be needed e.g. in Docker containers which
currently(?) can't use Linux kernel keyrings and need the credential
cache to be a normal file.

config.py

@@ -48,6 +48,11 @@ class BaseConfiguration(object):
     # Available log levels are: debug, info, warn, error.
     LOG_LEVEL = 'info'
 
+    # Settings for Kerberos
+    KRB_KEYTAB = None
+    KRB_PRINCIPAL = None
+    KRB_CCACHE = None
+
 
 class DevConfiguration(BaseConfiguration):
     LOG_BACKEND = 'console'

rida/builder.py

@@ -376,16 +376,18 @@ chmod 644 %buildroot/%_rpmconfigdir/macros.d/macros.modules
 
         authtype = koji_config.authtype
         if authtype == "kerberos":
-            keytab = getattr(koji_config, "keytab", None)
-            principal = getattr(koji_config, "principal", None)
+            ccache = getattr(config, "krb_ccache", None)
+            keytab = getattr(config, "krb_keytab", None)
+            principal = getattr(config, "krb_principal", None)
             if keytab and principal:
                 koji_session.krb_login(
                     principal=principal,
                     keytab=keytab,
+                    ccache=ccache,
                     proxyuser=None,
                 )
             else:
-                koji_session.krb_login()
+                koji_session.krb_login(ccache=ccache)
         elif authtype == "ssl":
             koji_session.ssl_login(
                 os.path.expanduser(koji_config.cert),

rida/config.py

@@ -75,6 +75,9 @@ class Config(object):
         self._log_backend = ""
         self._log_file = ""
         self._log_level = 0
+        self._krb_keytab = None
+        self._krb_principal = None
+        self._krb_ccache = "/tmp/krb5cc_rida"
 
     @property
     def system(self):
@@ -311,3 +314,27 @@ class Config(object):
     def log_level(self, s):
         level = str(s).lower()
         self._log_level = logger.str_to_log_level(level)
+
+    @property
+    def krb_keytab(self):
+        return self._krb_keytab
+
+    @krb_keytab.setter
+    def krb_keytab(self, s):
+        self._krb_keytab = s
+
+    @property
+    def krb_principal(self):
+        return self._krb_principal
+
+    @krb_principal.setter
+    def krb_principal(self, s):
+        self._krb_principal = s
+
+    @property
+    def krb_ccache(self):
+        return self._krb_ccache
+
+    @krb_ccache.setter
+    def krb_ccache(self, s):
+        self._krb_ccache = s