Add a new option to choose the Identity endpoint

Previously the admin Identity endpoint was hardcoded to be used. Now
that keystone has dropped v2 support, deploying an admin Identity
endpoint is no longer useful, so allow this to be changed by the
deployer. Keep the default as using the `admin` endpoint, but create
a deprecation message so that we can change the default in the future.

Partial-Bug: 1830002
Change-Id: I993a45ccb1109d67e65bf32d1e134cc9bec2d88e

6 files changed, 33 insertions, 9 deletions

diff --git a/doc/source/middlewarearchitecture.rst b/doc/source/middlewarearchitecture.rst
index bc1c504..123b841 100644
--- a/doc/source/middlewarearchitecture.rst
+++ b/doc/source/middlewarearchitecture.rst
@@ -174,11 +174,12 @@ when ``auth_plugin`` is set to ``password``.
     user_domain_name = Default
     username = nova
     password = ServicePassword
+    interface = public
     auth_url = http://127.0.0.1:5000
     # Any of the options that could be set in api-paste.ini can be set here.
 
 If using an ``auth_plugin``, connection to the Identity service will be
-established on the ``admin`` interface as registered in the service catalog.
+established on the ``interface`` as registered in the service catalog.
 In the case where you are using an ``auth_plugin`` and have multiple regions,
 also specify the ``region_name`` option to fetch the correct endpoint.
 
diff --git a/keystonemiddleware/auth_token/__init__.py b/keystonemiddleware/auth_token/__init__.py
index 72ba223..6041e9e 100644
--- a/keystonemiddleware/auth_token/__init__.py
+++ b/keystonemiddleware/auth_token/__init__.py
@@ -251,7 +251,6 @@ _LOG = logging.getLogger(__name__)
 _CACHE_INVALID_INDICATOR = 'invalid'
 oslo_cache.configure(cfg.CONF)
 
-
 AUTH_TOKEN_OPTS = [
     (_base.AUTHTOKEN_GROUP,
      _opts._OPTS + _auth.OPTS + loading.get_auth_common_conf_options())
@@ -570,6 +569,7 @@ class AuthProtocol(BaseAuthProtocol):
         self._include_service_catalog = self._conf.get(
             'include_service_catalog')
         self._hash_algorithms = self._conf.get('hash_algorithms')
+        self._interface = self._conf.get('interface')
 
         self._auth = self._create_auth_plugin()
         self._session = self._create_session()
@@ -907,7 +907,7 @@ class AuthProtocol(BaseAuthProtocol):
             self._session,
             auth=self._auth,
             service_type='identity',
-            interface='admin',
+            interface=self._interface,
             region_name=self._conf.get('region_name'),
             connect_retries=self._conf.get('http_request_max_retries'))
 
@@ -918,7 +918,8 @@ class AuthProtocol(BaseAuthProtocol):
             self.log,
             adap,
             include_service_catalog=self._include_service_catalog,
-            requested_auth_version=auth_version)
+            requested_auth_version=auth_version,
+            requested_auth_interface=self._interface)
 
     def _create_oslo_cache(self):
         # having this as a function makes test mocking easier
diff --git a/keystonemiddleware/auth_token/_identity.py b/keystonemiddleware/auth_token/_identity.py
index 36639a6..aeeb8d9 100644
--- a/keystonemiddleware/auth_token/_identity.py
+++ b/keystonemiddleware/auth_token/_identity.py
@@ -41,8 +41,10 @@ class _RequestStrategy(object):
 
     AUTH_VERSION = None
 
-    def __init__(self, adap, include_service_catalog=None):
+    def __init__(self, adap, include_service_catalog=None,
+                 requested_auth_interface=None):
         self._include_service_catalog = include_service_catalog
+        self._requested_auth_interface = requested_auth_interface
 
     def verify_token(self, user_token, allow_expired=False):
         pass
@@ -93,7 +95,10 @@ class _V3RequestStrategy(_RequestStrategy):
 
     def __init__(self, adap, **kwargs):
         super(_V3RequestStrategy, self).__init__(adap, **kwargs)
-        self._client = v3_client.Client(session=adap)
+        client_args = {'session': adap}
+        if self._requested_auth_interface:
+            client_args['interface'] = self._requested_auth_interface
+        self._client = v3_client.Client(**client_args)
 
     def verify_token(self, token, allow_expired=False):
         auth_ref = self._client.tokens.validate(
@@ -128,11 +133,12 @@ class IdentityServer(object):
     """
 
     def __init__(self, log, adap, include_service_catalog=None,
-                 requested_auth_version=None):
+                 requested_auth_version=None, requested_auth_interface=None):
         self._LOG = log
         self._adapter = adap
         self._include_service_catalog = include_service_catalog
         self._requested_auth_version = requested_auth_version
+        self._requested_auth_interface = requested_auth_interface
 
         # Built on-demand with self._request_strategy.
         self._request_strategy_obj = None
@@ -163,7 +169,8 @@ class IdentityServer(object):
 
             self._request_strategy_obj = strategy_class(
                 self._adapter,
-                include_service_catalog=self._include_service_catalog)
+                include_service_catalog=self._include_service_catalog,
+                requested_auth_interface=self._requested_auth_interface)
 
         return self._request_strategy_obj
 
diff --git a/keystonemiddleware/auth_token/_opts.py b/keystonemiddleware/auth_token/_opts.py
index 941d0ad..6231b6d 100644
--- a/keystonemiddleware/auth_token/_opts.py
+++ b/keystonemiddleware/auth_token/_opts.py
@@ -66,7 +66,11 @@ _OPTS = [
                ' favor of www_authenticate_uri and will be removed in the S'
                ' release.'),
     cfg.StrOpt('auth_version',
-               help='API version of the admin Identity API endpoint.'),
+               help='API version of the Identity API endpoint.'),
+    cfg.StrOpt('interface',
+               default='admin',
+               help='Interface to use for the Identity API endpoint. Valid'
+               ' values are "public", "internal" or "admin"(default).'),
     cfg.BoolOpt('delay_auth_decision',
                 default=False,
                 help='Do not handle authorization requests within the'
diff --git a/keystonemiddleware/tests/unit/test_opts.py b/keystonemiddleware/tests/unit/test_opts.py
index 3b4e510..143264c 100644
--- a/keystonemiddleware/tests/unit/test_opts.py
+++ b/keystonemiddleware/tests/unit/test_opts.py
@@ -33,6 +33,7 @@ class OptsTestCase(utils.TestCase):
         expected_opt_names = [
             'auth_admin_prefix',
             'auth_host',
+            'interface',
             'auth_port',
             'auth_protocol',
             'www_authenticate_uri',
@@ -86,6 +87,7 @@ class OptsTestCase(utils.TestCase):
         # This is the sample config generator list WITHOUT deprecations
         expected_opt_names = [
             'www_authenticate_uri',
+            'interface',
             'auth_uri',
             'auth_version',
             'delay_auth_decision',
diff --git a/releasenotes/notes/interface-option-ed551d2a3162668d.yaml b/releasenotes/notes/interface-option-ed551d2a3162668d.yaml
new file mode 100644
index 0000000..4771e86
--- /dev/null
+++ b/releasenotes/notes/interface-option-ed551d2a3162668d.yaml
@@ -0,0 +1,9 @@
+---
+features:
+  - |
+    [`bug 1830002 <https://bugs.launchpad.net/keystonemiddleware/+bug/1830002>`_]
+    In order to allow an installation to work without deploying an admin
+    Identity endpoint, a new option `interface` has been added, allowing
+    select the Identity endpoint that is being used when verifying auth
+    tokens. It defaults to `admin` in order to replicate the old behaviour,
+    but may be set to `public` or `internal` as needed.