Abstract authentication function

Abstract authentication function so plugins for other authentication
backends can be implemented in cases where keystone is not used. Currently,
mistral is hard coded to support keystone and keycloak. The domain/project
related trust that is specific to keystone is not addressed.

Change-Id: I21994ab20af519b2ba85efd7cbe043547988e5b3
Implements: blueprint mistral-abstract-auth

mistral/auth/__init__.py

@@ -0,0 +1,53 @@
+# Copyright 2016 - Brocade Communications Systems, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+
+import abc
+
+from oslo_config import cfg
+from oslo_log import log as logging
+import six
+from stevedore import driver
+
+from mistral import exceptions as exc
+
+
+LOG = logging.getLogger(__name__)
+
+_IMPL_AUTH_HANDLER = None
+
+
+def get_auth_handler():
+    auth_type = cfg.CONF.auth_type
+
+    global _IMPL_AUTH_HANDLER
+
+    if not _IMPL_AUTH_HANDLER:
+        mgr = driver.DriverManager(
+            'mistral.auth',
+            auth_type,
+            invoke_on_load=True
+        )
+
+        _IMPL_AUTH_HANDLER = mgr.driver
+
+    return _IMPL_AUTH_HANDLER
+
+
+@six.add_metaclass(abc.ABCMeta)
+class AuthHandler(object):
+    """Abstract base class for an authentication plugin."""
+
+    @abc.abstractmethod
+    def authenticate(self, req):
+        raise exc.UnauthorizedException()

mistral/auth/keycloak.py

@@ -0,0 +1,56 @@
+# Copyright 2016 - Brocade Communications Systems, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+
+from oslo_config import cfg
+from oslo_log import log as logging
+import pprint
+import requests
+
+from mistral import auth
+
+
+LOG = logging.getLogger(__name__)
+
+CONF = cfg.CONF
+
+
+class KeycloakAuthHandler(auth.AuthHandler):
+
+    def authenticate(self, req):
+        realm_name = req.headers.get('X-Project-Id')
+
+        # NOTE(rakhmerov): There's a special endpoint for introspecting
+        # access tokens described in OpenID Connect specification but it's
+        # available in KeyCloak starting only with version 1.8.Final so we have
+        # to use user info endpoint which also takes exactly one parameter
+        # (access token) and replies with error if token is invalid.
+        user_info_endpoint = (
+            "%s/realms/%s/protocol/openid-connect/userinfo" %
+            (CONF.keycloak_oidc.auth_url, realm_name)
+        )
+
+        access_token = req.headers.get('X-Auth-Token')
+
+        resp = requests.get(
+            user_info_endpoint,
+            headers={"Authorization": "Bearer %s" % access_token},
+            verify=not CONF.keycloak_oidc.insecure
+        )
+
+        resp.raise_for_status()
+
+        LOG.debug(
+            "HTTP response from OIDC provider: %s" %
+            pprint.pformat(resp.json())
+        )

mistral/auth/keystone.py

@@ -0,0 +1,45 @@
+# Copyright 2016 - Brocade Communications Systems, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+
+from oslo_config import cfg
+from oslo_log import log as logging
+
+from mistral import auth
+from mistral import exceptions as exc
+
+
+LOG = logging.getLogger(__name__)
+
+CONF = cfg.CONF
+
+
+class KeystoneAuthHandler(auth.AuthHandler):
+
+    def authenticate(self, req):
+        # Note(nmakhotkin): Since we have deferred authentication,
+        # need to check for auth manually (check for corresponding
+        # headers according to keystonemiddleware docs.
+        identity_status = req.headers.get('X-Identity-Status')
+        service_identity_status = req.headers.get('X-Service-Identity-Status')
+
+        if (identity_status == 'Confirmed' or
+                service_identity_status == 'Confirmed'):
+            return
+
+        if req.headers.get('X-Auth-Token'):
+            msg = 'Auth token is invalid: %s' % req.headers['X-Auth-Token']
+        else:
+            msg = 'Authentication required'
+
+        raise exc.UnauthorizedException(msg)

mistral/context.py

@@ -22,9 +22,8 @@ from oslo_serialization import jsonutils
 from osprofiler import profiler
 import pecan
 from pecan import hooks
-import pprint
-import requests
 
+from mistral import auth
 from mistral import exceptions as exc
 from mistral import utils
 
@@ -260,10 +259,8 @@ class AuthHook(hooks.PecanHook):
             return
 
         try:
-            if CONF.auth_type == 'keystone':
-                authenticate_with_keystone(state.request)
-            elif CONF.auth_type == 'keycloak-oidc':
-                authenticate_with_keycloak(state.request)
+            auth_handler = auth.get_auth_handler()
+            auth_handler.authenticate(state.request)
         except Exception as e:
             msg = "Failed to validate access token: %s" % str(e)
 
@@ -274,54 +271,6 @@ class AuthHook(hooks.PecanHook):
             )
 
 
-def authenticate_with_keystone(req):
-    # Note(nmakhotkin): Since we have deferred authentication,
-    # need to check for auth manually (check for corresponding
-    # headers according to keystonemiddleware docs.
-    identity_status = req.headers.get('X-Identity-Status')
-    service_identity_status = req.headers.get('X-Service-Identity-Status')
-
-    if (identity_status == 'Confirmed' or
-            service_identity_status == 'Confirmed'):
-        return
-
-    if req.headers.get('X-Auth-Token'):
-        msg = 'Auth token is invalid: %s' % req.headers['X-Auth-Token']
-    else:
-        msg = 'Authentication required'
-
-    raise exc.UnauthorizedException(msg)
-
-
-def authenticate_with_keycloak(req):
-    realm_name = req.headers.get('X-Project-Id')
-
-    # NOTE(rakhmerov): There's a special endpoint for introspecting
-    # access tokens described in OpenID Connect specification but it's
-    # available in KeyCloak starting only with version 1.8.Final so we have
-    # to use user info endpoint which also takes exactly one parameter
-    # (access token) and replies with error if token is invalid.
-    user_info_endpoint = (
-        "%s/realms/%s/protocol/openid-connect/userinfo" %
-        (CONF.keycloak_oidc.auth_url, realm_name)
-    )
-
-    access_token = req.headers.get('X-Auth-Token')
-
-    resp = requests.get(
-        user_info_endpoint,
-        headers={"Authorization": "Bearer %s" % access_token},
-        verify=not CONF.keycloak_oidc.insecure
-    )
-
-    resp.raise_for_status()
-
-    LOG.debug(
-        "HTTP response from OIDC provider: %s" %
-        pprint.pformat(resp.json())
-    )
-
-
 class ContextHook(hooks.PecanHook):
     def before(self, state):
         set_ctx(context_from_headers_and_env(

setup.cfg

@@ -75,3 +75,7 @@ mistral.yaql_functions =
     execution = mistral.utils.yaql_utils:execution_
     env = mistral.utils.yaql_utils:env_
     uuid = mistral.utils.yaql_utils:uuid_
+
+mistral.auth =
+    keystone = mistral.auth.keystone:KeystoneAuthHandler
+    keycloak-oidc = mistral.auth.keycloak:KeycloakAuthHandler