raise_exc default in Adapter

It can be annoying to have to say raise_exc=False (or use try/except) on
every call when talking to an API where 4xx response codes are
useful/normal/informative or where the preferred coding style is to use
conditionals rather than try/except.

With this change, the Adapter constructor takes a new kwarg, raise_exc.
It defaults to None, and the existing behavior is unchanged.  If set to
a boolean value, that is used as the default for requests.  Specifying
raise_exc to the primitives (get, head, put, post, patch, delete,
request) at any point along the chain will still take precedence.

Change-Id: Ie291c3cb891467728d8ca33cf62afdab37c82f34
Closes-Bug: #1776501

keystoneauth1/adapter.py

@@ -88,6 +88,10 @@ class Adapter(object):
                                         should be retried (optional,
                                         defaults to HTTP 503, has no effect
                                         when status_code_retries is 0).
+    :param bool raise_exc: If True, requests returning failing HTTP responses
+                           will raise an exception; if False, the response is
+                           returned. This can be overridden on a per-request
+                           basis via the kwarg of the same name.
     """
 
     client_name = None
@@ -102,7 +106,7 @@ class Adapter(object):
                  global_request_id=None,
                  min_version=None, max_version=None,
                  default_microversion=None, status_code_retries=None,
-                 retriable_status_codes=None):
+                 retriable_status_codes=None, raise_exc=None):
         if version and (min_version or max_version):
             raise TypeError(
                 "version is mutually exclusive with min_version and"
@@ -131,6 +135,7 @@ class Adapter(object):
         self.default_microversion = default_microversion
         self.status_code_retries = status_code_retries
         self.retriable_status_codes = retriable_status_codes
+        self.raise_exc = raise_exc
 
         self.global_request_id = global_request_id
 
@@ -202,6 +207,9 @@ class Adapter(object):
             kwargs.setdefault('headers', {}).setdefault(
                 "X-OpenStack-Request-ID", self.global_request_id)
 
+        if self.raise_exc is not None:
+            kwargs.setdefault('raise_exc', self.raise_exc)
+
         return self.session.request(url, method, **kwargs)
 
     def get_token(self, auth=None):

keystoneauth1/tests/unit/test_session.py

@@ -1580,6 +1580,33 @@ class AdapterTest(utils.TestCase):
         validate({'default_microversion': '1.2'}, {'microversion': '1.5'},
                  {'microversion': '1.5'})
 
+    def test_raise_exc_override(self):
+        sess = client_session.Session()
+        url = 'http://url'
+
+        def validate(adap_kwargs, get_kwargs, exp_kwargs):
+            with mock.patch.object(sess, 'request') as m:
+                adapter.Adapter(sess, **adap_kwargs).get(url, **get_kwargs)
+                m.assert_called_once_with(url, 'GET', endpoint_filter={},
+                                          **exp_kwargs)
+
+        # No raise_exc in Adapter or get()
+        validate({}, {}, {})
+
+        # Set in Adapter, unset in get()
+        validate({'raise_exc': True}, {}, {'raise_exc': True})
+        validate({'raise_exc': False}, {}, {'raise_exc': False})
+
+        # Unset in Adapter, set in get()
+        validate({}, {'raise_exc': True}, {'raise_exc': True})
+        validate({}, {'raise_exc': False}, {'raise_exc': False})
+
+        # Setting in get() overrides the one in Adapter
+        validate({'raise_exc': True}, {'raise_exc': False},
+                 {'raise_exc': False})
+        validate({'raise_exc': False}, {'raise_exc': True},
+                 {'raise_exc': True})
+
 
 class TCPKeepAliveAdapterTest(utils.TestCase):